JP2810531B2 - Method and apparatus for forming deposited film - Google Patents

Description

Description: TECHNICAL FIELD The present invention uses a novel microwave energy supply device capable of generating a uniform microwave plasma over a large area, and a plasma reaction caused by the new microwave energy supply device.
The present invention relates to a method and an apparatus for continuously forming a functional deposition film whose composition is controlled over a large area by decomposing and exciting a source gas.

More specifically, there is provided a method and apparatus capable of dramatically increasing the utilization efficiency of the raw material gas and capable of continuously forming a functional deposition film having high uniformity at high speed over a large area. Can realize mass production of large-area thin-film semiconductor devices such as photovoltaic elements at low cost.

[Description of Prior Art]

Electricity demand is ever increasing worldwide, and how to produce electric power to meet such demand is being considered as a global issue. Electricity is currently produced by hydro, thermal and nuclear power.
Among these power generation methods, hydroelectric power generation uses rainfall, but cannot constantly produce a predetermined amount of power. Thermal power generation uses so-called fossil fuels such as petroleum and coal, and most of the power demand is covered by this power generation method.However, fossil fuels are limited, and it is inevitable for power generation. There is a debate about the necessity of switching to another power generation method because of the inherent problem that carbon dioxide emitted from the country will cause global warming in the future.

As a result, nuclear power has come to the forefront of attention, and the ratio of electricity production by nuclear power tends to increase. However, nuclear power generation is at risk of causing radioactive contamination, a serious problem related to the survival of all living organisms, and it is essential to ensure its safety. I have.

In view of the above background, "photovoltaic power generation" has recently attracted much attention, and many proposals have already been made. However, none of the proposed solar power generation systems is capable of producing electric power from the viewpoint of meeting the electric power demand. By the way, the photovoltaic power generation methods proposed so far can be roughly classified into the following two methods. Method A: Concentrate sunlight, heat water, boil it to generate steam (photothermal conversion), and generate electricity with a boiler (Thermoelectric conversion).

Method B: electricity is generated by the photoelectric conversion action of a solar cell.

The photovoltaic power generation system of system A is a system in which power is generated after two-stage energy conversion, the conversion efficiency of the system is low, and small plant experiments have been started but have not yet been put to practical use.

On the other hand, many proposals have already been made for the solar power generation system of system B, and some of them have been put to practical use for consumer power sources such as wristwatches and desk calculators. The power generation facilities are small-scale, and experiments are being conducted, but at present they are still in the research stage.

The reason for this is that there are some issues to be overcome for the constant production of large-scale power, especially large-area solar cells that enable large-scale power production because the power generation capacity is proportional to the area of the solar cell. The biggest challenge is whether batteries can be produced on an industrial scale. By the way, as for a solar cell, a semiconductor junction such as a so-called pn junction and a pin junction is formed in a semiconductor layer as an important constituent member. These semiconductor junctions are formed by stacking semiconductor layers of different conductivity types, implanting a dopant of a different conductivity type into a semiconductor layer of one conductivity type by ion implantation, or diffusing it by thermal diffusion. Is done. There are many proposals for materials for forming the semiconductor layer, and these proposals are based on single crystal or polycrystalline silicon (hereinafter abbreviated as “x-Si”) and amorphous silicon (hereinafter “A-Si”). ") And compound semiconductor materials.

However, even when using any of these materials, uniformity, reproducibility, etc., manufacturing problems, photoelectric conversion efficiency problems, manufacturing cost problems, etc. The manufacturing method for producing solar cells and the element structure of solar cells themselves have not yet been completed.

In particular, solar cell panels using single-crystal Si are manufactured by ion-implanting Si wafers cut out of silicon ingots to form pn junctions, connecting them as closely as possible, and connecting them. However, the manufacturing process of solar cell elements cannot be said to be a method suitable for processing large-sized substrates in large quantities, and large-diameter single-crystal silicon ingots are extremely expensive in the first place, and the process of cutting out Si wafers In, many parts that cannot be used as cutting margins are discharged. These are single crystal Si
It is also a factor that increases the production cost of solar cells.
And there is currently no effective way to solve these problems. Regarding solar cells using polycrystalline Si, although the photoelectric conversion efficiency is slightly higher than that of solar cells using A-Si, the technology for controlling the crystal grain size, which is one of the characteristic determinants, is incomplete, The device manufacturing process is single-crystal Si
It is almost the same as solar cells and is not a suitable method for mass production.

In addition, regardless of whether it is single crystal or polycrystalline, x-Si is fragile because of its crystal-specific properties, so it requires strict protection for outdoor photovoltaic power generation. Solar panels and units are quite heavy and are constrained by installation location and environment.

On the other hand, in the manufacture of large-area solar cells using A-Si, a source gas containing an element serving as a dopant such as phosphine (PH ₃ ) or diborane (B ₂ H ₆ ) is mixed with silane or the like as a main source gas. A semiconductor film having a desired conductivity type is obtained by glow discharge decomposition, and a semiconductor junction can be easily formed by sequentially laminating these semiconductor films on a desired substrate. It is known that it can be manufactured much cheaper than when used.

Then, for performing the above-described glow discharge decomposition, RF
(Radio frequency) glow discharge decomposition techniques have been established in the art and are becoming widely used. However, in this method, when a semiconductor film is formed at a low deposition rate, a relatively high-quality semiconductor film is formed. Therefore, a high-quality semiconductor film sufficient to function as a solar cell is formed at high speed over a large area. It has been extremely difficult to produce solar cells on an industrial scale so as to meet the power demand.

On the other hand, as a method capable of forming a high-quality deposited film at a high speed, a plasma process using a microwave has attracted attention. Since the microwave has a short frequency band, the power density in the film formation chamber can be increased as compared with the case where the conventional RF is used, and is suitable for efficiently generating and connecting plasma.

For example, U.S. Pat.Nos. 4,517,223 and 4,50
No. 4,518 discloses a method in which a glow discharge is generated by microwave power to form a deposited film on a substrate at a low pressure. According to these publications, since these deposited film forming methods form a film under a low pressure, there is little recombination of radicals which causes deterioration of the properties of the deposited film when a large power is applied. In addition, the generation of fine powder composed of polysilane or the like in plasma is small, and the film forming speed can be improved. It is understood that there are such advantages. However, the plasma process using microwaves has a problem that the plasma density is likely to be non-uniform since the wavelength of microwaves is extremely short, approximately one-180th of that of conventional RF.

As an example of avoiding such a problem, there is an attempt to use a slow-wave circuit as a microwave power supply means for equalizing microwave power in a film formation chamber. However, the slow-wave circuit is distant from a microwave oscillator. As a result, there is a specific problem that the microwave power supplied from the microwave feeding means to the plasma rapidly attenuates. In order to solve this problem, a method has been attempted in which the distance between the substrate to be processed and the microwave feeding means is gradually reduced in the direction in which the microwave travels to make the power density near the substrate constant.

For example, U.S. Pat.Nos. 3,814,983 and 4,52
No. 1,717 discloses such a method.
The former describes that it is necessary to incline the microwave power supply means at a certain angle with respect to the substrate, but the efficiency of transmitting microwave power to plasma is not satisfactory. Further, in the latter case, it is disclosed that a microwave power supply unit which is two non-parallel slow wave circuits is provided in a plane parallel to the base. That is,
The central axis of the microwave feeding means is in a plane parallel to the base,
In addition, it is desirable that they are arranged so as to intersect with each other on a straight line perpendicular to the direction of movement of the substrate, and in order to avoid interference between the two microwave feeding means, the microwave feeding means should be connected to the long side of the waveguide. Are disposed so as to be displaced laterally with respect to the moving direction of the substrate by half the length of the substrate.

Among the microwave feeding means, an antenna system that is relatively easy to handle is described in, for example, Japanese Patent Publication No. 57-53858 and Japanese Patent Application Laid-Open No. 61-283116 shown in FIGS. 16 and 17. There is a microwave plasma CVD apparatus.
In any case, the periphery of the antenna is surrounded by a cylindrical body made of a microwave-permeable substance, which keeps the airtight inside the film forming chamber and allows microwaves to be introduced from outside the film forming chamber. In addition, the life of the antenna can be improved by preventing film deposition on the antenna, and a high-density plasma can be generated over a wide pressure range. However, in the apparatus shown in FIG. 17, a substrate 1703 placed on a substrate holder 1702 and microwave power supply means are arranged in a reaction vessel 1701. 1704 is a coaxial line as the microwave power supply means, and the microwave power is transmitted from a gap 1705 provided by cutting out a part of the outer conductor of the coaxial line 1704 through a microwave transparent cylinder 1706. It is charged into the reaction vessel 1701. However, with this apparatus, it is clearly difficult to form an A-Si film uniformly on a large-area substrate, and there is no specific disclosure. on the other hand,
In the apparatus shown in FIG. 16, a rod antenna 1602 as a microwave power supply means, a gas supply port 1603, and a gas exhaust port 16 connected to a vacuum pump 1604 are provided in a reaction vessel 1601.
05 and a substrate 1607 mounted on the quartz cylinder 1606 are provided. The microwave power generated by the microwave oscillator is transmitted through the waveguide 1608 and is injected into the space surrounded by the quartz cylinder 1606 via the rod antenna 1602 and the microwave transmitting member 1609 to generate plasma. Plasma processing is performed. However, microwave power is
Due to the inherent property of the antenna that it is sequentially radiated into space while propagating on the antenna, the microwave power is attenuated in the longitudinal direction of the rod antenna, so that the plasma is made uniform in the longitudinal direction. It is difficult.

Further, in a cavity resonator method known as another microwave power feeding means, some proposals have been made for maintaining plasma uniformity. These proposals are described, for example, in Journal of Vacuum Science Technology B-
4 (January-February 1986) pages 295-298 and B-4 of the same journal
(January-February 1986) found in the report on pages 126-130. According to these reports, a cylindrical cavity resonator type microwave reactor called a microwave plasma disk source (abbreviated as MPDS) has been proposed. That is, the plasma has a disk shape and is included in the cylindrical cavity resonator as a part thereof, and its diameter is a function of the microwave frequency. These reports show that the MPDS was equipped with a variable cavity length mechanism so that it could be tuned to microwave frequencies. In the MPDS designed to operate at 2.45 GHz, the confinement diameter of the plasma is at most about 10 cm,
The plasma volume is at most about 118 cm ³ , which cannot be said to be a large area at all. Also, the report states that for systems designed to operate at frequencies as low as 915 MHz, lowering the frequency could result in a plasma diameter of about 40 cm, and 2000 cm.
A plasma volume of ³ is given.

Also, the report further states that the lower frequency, e.g., 400M
By operating at Hz, the discharge can be extended to diameters exceeding 1 m. However, in order to achieve this, a dedicated high-power microwave oscillator must be developed, and even if it is completed, the frequency that can be used industrially is restricted by the Radio Law to avoid communication failures. Implementation is difficult.

Further, a system utilizing electron cyclotron resonance (ECR) as another microwave feeding means has been proposed in Japanese Patent Application Laid-Open Nos. 55-141729 and 57-133636. That is, in this method, an electromagnet is arranged coaxially around a cavity resonator that becomes a plasma chamber, and 875
A Gaussian magnetic field is formed in the vicinity of the microwave introduction window, and electron cyclotron resonance (ECR) conditions are satisfied to increase the microwave absorptivity to plasma and generate high-density plasma. And the high-density plasma is transported along a divergent magnetic field formed by the electromagnet,
A desired deposited film is formed on a desired substrate.

This method is based on the microwave plasma disk
The source (MPDS) method is similar in that it uses a cavity resonator, but the MPDS method occupies only a part of the inside of the cavity resonator, whereas the ECR method described above uses a cavity. The difference is that the inside of the resonator is filled with plasma and that the electron cyclotron resonance phenomenon is used.

Incidentally, a number of examples of forming various semiconductor thin films using high-density plasma formed by the ECR method have been reported by academic societies and the like. And this kind of microwave ECR plasma CVD apparatus has already been commercialized.

However, in these ECR-based methods, the divergent magnetic field applied from outside the cavity resonator is used to control the plasma, so the magnetic field distribution created by the electromagnet on the substrate surface becomes non-uniform and large-area substrates can be used. It is very difficult to form a uniform and uniform deposited film.

Japanese Patent Application Laid-Open No. 63-283018 discloses a method that partially overcomes this difficulty and improves the film thickness / film quality distribution. That is, in order to generate a uniform magnetic field distribution, another magnetic field generating means (for example, a second electromagnet) different from the electromagnet disposed around the cavity resonator is disposed around the base, and a uniform magnetic field is generated. This achieves the film thickness / film quality distribution. However,
This second electromagnet is already enormous, and at the moment the device is composed of at most 15
In reality, only uniformity of film quality and thickness of about cmφ can be obtained.

In addition to the establishment of a high-frequency power supply means such as RF or microwave as described above, a continuous method for manufacturing a solar cell element by forming a semiconductor junction by sequentially stacking a plurality of semiconductor films having a desired conductivity type. A film forming apparatus must also be established.

As an example of such a continuous film forming apparatus, a plurality of independent film-forming materials for forming a plurality of semiconductor films are connected via a gate valve, and a pair of parallel plate type RF electrodes are provided in the film forming chamber. There has been proposed a continuous film forming apparatus in which each semiconductor film is deposited and formed by RF glow discharge decomposition in a state where each of the film forming chambers is separated from other film forming chambers. That is, a so-called three-chamber separation type continuous film forming apparatus has been proposed as a continuous film forming apparatus for a stacked semiconductor device having a pin junction. The gate valve is used to form a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer. Each deposition layer is separated, and each layer is deposited by RF glow discharge decomposition method.However, in the process of laminating each layer, a cycle of deposition → exhaust → transport → deposition is repeated, so a large deposition time In addition, since the width of the base is restricted by the gate valve, a continuous film forming apparatus that can produce a large amount of solar cell elements that can be replaced with the current power generation method is hardly possible.

On the other hand, the roll-to-roll type continuous film forming apparatus disclosed in U.S. Pat. No. 4,400,409 has few restrictions on the film forming time and the width of the substrate as described above and is practical. It is a target. According to this apparatus, a plurality of RF glow discharge regions are provided along a path along which a sufficiently long flexible band-shaped substrate having a desired width is conveyed, and a semiconductor film mainly composed of A-Si is provided in each of the RF glow discharge regions. To form
It is said that by continuously transporting the strip-like substrate substantially horizontally in its longitudinal direction, an element having a semiconductor junction composed of semiconductor films corresponding to the number of RF glow discharge regions can be continuously formed. In this specification, the dopant gas used when forming each semiconductor film is other RF gas.
A gas gate is used to prevent diffusion and mixing into the glow discharge region. Specifically, the gasket separates the respective RF glow discharge regions from each other by a slit-like gas isolation road, and further separates the RF glow discharge regions into, for example, A
r, means for forming a flow of the exhaust gas such as H ₂ is employed.

However, since the formation of each semiconductor layer is performed by a plasma CVD method using RF (radio frequency), it is naturally a limit to improve the film deposition rate while maintaining the characteristics of a continuously formed film. There is. That is, for example, even when a semiconductor layer having a thickness of at most 5000 ° is formed, the film deposition rate is slow, so that a predetermined plasma is always generated over a large area in a considerably long direction in the transport direction of the band-shaped substrate, and It is necessary to keep the plasma uniform. However, doing so requires considerable skill and it is difficult to generalize the various plasma control parameters involved. In addition, the decomposition efficiency and utilization efficiency of the film-forming source gas used are not high, which is one of the factors for raising the production cost.

In addition, JP-A-61-288074 discloses a deposited film forming apparatus using an improved roll-to-roll continuous film forming method. In this apparatus, a curved portion is formed in a part of a flexible continuous belt-shaped member installed in a reaction vessel, and active species generated from a source gas in an activation space different from the reaction vessel are formed therein. After being transported to the reaction vessel, it is introduced into the reaction vessel and chemically interacts with thermal energy to form a deposited film on the inner surface of the belt-shaped member forming the curved portion. By depositing on the inner surface of the curved portion in this way, the device can be made compact. Further, since active species that have been activated in advance are used, the film forming speed can be increased as compared with a conventional deposited film forming apparatus.

However, this device utilizes a deposited film forming reaction due to chemical interaction in the presence of thermal energy, and thus a method of supplying thermal energy, the tendency of a reaction between active species and other molecules to occur, or The distance between the reaction vessel of the deposition film forming apparatus and the activation space and the film formation conditions are restricted depending on the life until the deactivation of the active species, and it is difficult to increase the area.

By the way, thin-film semiconductors have a large area or a long size, such as thin-film transistors (TFTs) for driving pixels of liquid crystal displays, photoelectric conversion elements for contact-type image sensors, and switching elements, in addition to the above-mentioned applications for solar cells. It is also suitably used for the production of thin film semiconductor devices that need to be used, and is partially used as a key component for the image input / output device. By providing a deposited film formation method,
It is expected that it will become more widely spread.

[Object of the invention]

The present invention overcomes the above-mentioned problems in the conventional method and apparatus for forming a thin-film semiconductor device and provides a novel method and apparatus for forming a high-quality functional deposition film uniformly over a large area at a high speed. The purpose is to provide.

It is another object of the present invention to provide a method and an apparatus for forming a functional deposition film having a chemical composition that changes continuously in the longitudinal direction from a continuously moving strip member.

A further object of the present invention is to provide a method and apparatus capable of dramatically increasing the utilization efficiency of a source gas for forming a deposited film and realizing mass production of thin film semiconductor devices at low cost.

It is yet another object of the present invention to provide a method and apparatus for generating a substantially uniform plasma over a large area and a large volume.

Still another object of the present invention is to provide a method and an apparatus for forming a semiconductor layer having a forbidden band width continuously changing in the longitudinal direction from a continuously moving band-shaped member.

It is still another object of the present invention to provide a method and an apparatus for forming a semiconductor layer having a valence electron density continuously changing in the vertical direction from a continuously moving strip member.

Still another object of the present invention is to provide a novel method and apparatus for forming a photovoltaic device having a high efficiency and a high photoelectric conversion efficiency continuously on a relatively wide and long substrate. Is to do.

[Structure and effect of the invention]

The present inventors have solved the above-mentioned problems in the conventional semiconductor deposited film forming apparatus and have conducted intensive research to achieve the object of the present invention. A microwave antenna means is contained and rushed into the film formation chamber by including a microwave permeable member, and a raw material gas for film formation is introduced into the film formation chamber, and an appropriate pressure at which gas diffusion easily occurs. The microwave was supplied from a microwave power source to the microwave antenna means, and further, a bias voltage was applied to bias applying means disposed separately from the belt-shaped member. It has been found that uniform microwave plasma can be generated in the longitudinal direction of the microwave antenna, and that the plasma potential can be controlled.

The present invention has been completed as a result of further studies based on the above-mentioned findings, and continuously forms a large-area functional deposited film by a microwave plasma CVD method having a main point as described below. Methods and apparatus.

 The method of the present invention is as follows.

That is, the band-shaped member is moved in the longitudinal direction, and a film-forming space having a side wall on the band-shaped member is formed on the way, and at least two or more kinds of deposited films having different compositions are formed in the formed film-forming space. Each of the raw material gases is separately introduced through a plurality of gas supply means, and simultaneously, in a microwave traveling direction through microwave antenna means surrounded by a microwave transmitting member arranged in the film forming space. Microwaves are radiated uniformly in all directions perpendicular to the film, microwave power is applied to the film formation space to generate microwave plasma in the film formation space, and the microwave plasma is exposed to the microwave plasma. This is a deposition forming method using a microwave plasma CVD method, wherein a deposited film is formed on the strip-shaped member constituting the side wall.

In the method of the present invention, in the middle of the moving belt-shaped member, the band-shaped member is formed between the curved start end forming unit and the curved end end forming unit by using a curved start end forming unit and a curved end end forming unit. The band-shaped member is curved leaving a gap in the longitudinal direction of the member so as to form a side wall of the film forming space.

Further, in the method of the present invention, as the material of the band-shaped member, a material having a linear expansion coefficient larger than the linear expansion coefficient of the deposited film to be formed is used, and the band-shaped member is heated to a desired film forming temperature of room temperature or higher. When a deposited film is formed on a concave curved surface that is formed by continuously bending while maintaining the same, and the band member on which the deposited film is formed is cooled to room temperature outside the film forming space, the band member is flattened. And let it cool down.

Then, the microwave antenna unit is rushed into the film-forming space from one of the opposite end surfaces of the columnar film-forming space formed with the band-shaped member as a side wall, and the microwave is introduced into the film-forming space. Turn on the power.

Further, through a microwave transmitting member provided between the microwave antenna means and the film forming space, microwave power is supplied from the microwave antenna means into the film forming space, and The microwave transmitting means separates the microwave antenna means from plasma generated in the film forming chamber.

In the method of the present invention, each of the gas supply means is disposed in parallel with a width direction of a band-shaped member constituting the side wall, and the raw material gas for forming a deposited film is discharged in one direction toward the adjacent band-shaped member. Let it do.

In the method of the present invention, the outer diameter of the microwave permeable member is adjusted and selected in advance according to the complex permittivity of the plasma.

Further, at least a conductive treatment is performed on a surface of the band-shaped member that is exposed to the microwave plasma.

 Further, the device of the present invention has the following contents.

That is, a deposition film forming apparatus for moving a belt-like member in the longitudinal direction and forming a deposition film on the belt-like member in the middle thereof, wherein a predetermined space is provided between the belt-like members in the longitudinal direction to support the belt-like member. To form a film-forming space that is provided in the middle of the longitudinal movement from the feeding mechanism to the winding mechanism by a set of rollers arranged in parallel with each other, and the band-shaped member functions as a wall. A film-forming space forming means for supporting the band-shaped member, and a microwave transmitting member arranged in the film-forming space for uniformly radiating the microwaves in all directions perpendicular to the traveling direction of the microwave; Microwave antenna means, exhaust means for exhausting the inside of the film formation space, at least two or more gas supply means for introducing a source gas for forming a deposited film into the film formation space, Serial and temperature control means for heating or cooling the belt-shaped member, a deposited film forming apparatus characterized by having a city.

In the apparatus of the present invention, the curved portion forming means includes a curved start end forming roller, a curved end end forming roller, and a facing curved portion end surface support ring, and the curved start end forming roller and the curved end end forming roller are , Are arranged in parallel with a gap left in the longitudinal direction of the band-shaped member.

In the apparatus of the present invention, the center conductor of the microwave coaxial line is protruded into the interior of the deposition chamber from one of the opposite end surfaces of the deposition chamber, and the center conductor of the deposition chamber is The belt-like member is disposed near the center axis substantially in parallel with the width direction of the band-shaped member.

In the device of the present invention, the center conductor separating means formed of the microwave permeable member is rotationally symmetric, and may have any shape of a cylinder, a truncated cone, or a cone.

Further, in the apparatus of the present invention, at least two tuning means are provided on the microwave coaxial line, one of which serves as an insertion length adjusting mechanism of the center conductor inserted into the film forming chamber. You.

Further, at least a conductive treatment is applied to a surface of the band-shaped member on a side exposed to the microwave plasma.

In the apparatus of the present invention, each of the gas supply means is disposed in parallel with a width direction of a belt-like member constituting the side wall.

Further, the gas supply means is provided with a gas discharge hole directed to a belt-like member constituting the adjacent side wall.

[Experiment]

Various experiments were conducted using the apparatus of the present invention to examine conditions for generating microwave plasma for uniformly forming a high-quality functional deposited film on a strip-shaped member. I do.

At the time of the experiment, the raw material gas was evenly introduced from three gas introduction pipes.

Experimental Example 1 In this example, the stability of the plasma, the film thickness distribution, and the distribution of the film chamber when the inner diameter of the film forming chamber was changed in a columnar film forming chamber were examined.

Specifically, five types of samples were produced according to the film forming conditions shown in Table 1 by using the apparatus of Example 1 to be described later while changing only the inner diameter of the film forming chamber. In addition, this study was performed in a state where the belt-shaped member was stationary.

Table 2 shows the evaluation results on the state of plasma and the like when the inner diameter of the film forming chamber is variously changed.

In the case where the inner diameter of the film forming chamber shown in Table 2 was 180 mmφ and 120 mmφ, the first except that the microwave power was 2500 W
When plasma was generated under the same conditions as shown in the table, the discharge was stabilized when the inner diameter of the film forming chamber was 120 mmφ, but when the inner diameter of the film forming chamber was 180 mmφ, the discharge was generated, but not stable. It was stable and not practical.

Next, characteristics of the samples 2-1 to 2-4 were evaluated by an evaluation method described below.

The thickness of the deposited film is MCPD-2 manufactured by Union Giken Co., Ltd.
It was calculated from the peak position of the multiple interference fringe of the spectral reflectance curve measured using a 00 type spectral reflectance measuring instrument. The measurement location of the film thickness in each sample was set at every 50 mm along the width direction (x) and the longitudinal direction (y) of the substrate. Next, this A-
A chromium thin film was deposited on the Si: H film by about 70 ° to form an ohmic electrode. Then, a dark conductivity (σ _d ) was obtained from a current value obtained by applying a voltage between the ohmic electrode and the SUS430BA (0.2 mm thick) thin plate used as the belt-shaped member in the dark. While applying He, the photoconductivity (σ _p ) was obtained from the value of the current flowing by irradiating He-Ne laser light from the Cr electrode side, and each characteristic distribution was evaluated. The irradiation intensity of the He-Ne laser light into the A-Si: H film is 4 × 10 ¹⁵ / photon number in consideration of the absorption of the Cr electrode.
cm ² · sec.

FIG. 7A shows the film thickness distribution in the x direction of the samples 2-1 to 2-3, FIG. 7B shows the film thickness distribution in the y direction, and FIG. 8A.
The sigma _d, sigma x-direction distribution of _p, sigma _d in FIG. 8 (b), σ
The respective measurement results of the distribution of _{p in} the y direction are shown. here,
x = 0 indicates the center in the width direction of the band-shaped member, and y = 0 indicates the center when the band-shaped member is developed in the longitudinal direction.

From these measurement results, in the width direction of the band-like member, the film thickness and film quality are both good in uniformity, but the film thickness to be deposited decreases as the internal pressure of the film forming chamber increases, and in the longitudinal direction of the band-like member. Although the uniformity of the film thickness is maintained, the characteristics of Sample 2-1 are clearly deteriorated. That is, as the inner diameter of the film forming chamber increases, the characteristics of the formed A-Si: H film tend to deteriorate.

In the sample 2-4, since the band members are very close to each other coaxially, the plasma density is considerably higher than that of the other samples, so that the substrate temperature becomes 350 ° C. or more. Therefore, peeling of the film occurred after the film formation, and the evaluation was not endurable.

Experimental Example 2 In this experimental example, using the apparatus of the present invention shown in FIG. 1 (see Example 1 to be described later) and a conventional RF glow discharge decomposition apparatus (not shown) under the conditions shown in Table 3. A change in the compressive stress in the deposited film was examined by forming the deposited film and measuring the strain amount of the substrate before and after the formation of the deposited film. Here, the Young's modulus of the stainless steel forming the band-shaped member is 2.04 × 10 ⁴ [kg / mm ² ], and the linear expansion coefficient is 11.9.
× 10 ^-6 [° C. ^-1 ].

As a result, no peeling of the deposited film was observed in any of the devices, but the measurement results of the compressive stress actually accumulated in the deposited film were obtained using the conventional device shown in FIG. In contrast, when the apparatus of the present invention shown in FIG. 1 is used, the weight is 32 kg / mm ² , which is 9 kg / mm ^2, and the stress is relaxed to about 1 / 3.5. I found out.

EXPERIMENTAL EXAMPLE 3 In this experimental example, a method for applying a pressure difference between the inside and the outside of the film-forming space using the apparatus shown in FIG. 1 and variously changing the width of the slit opening under the manufacturing conditions shown in Table 3 above. An experiment for depositing an A-Si: H film was performed under the same manufacturing conditions except that the deposition was performed.

 Table 4 shows the results and evaluations of the experiment.

The effective conductance C _ef [1 / sec] in the table is obtained by converting the flow rate from [sccm] to [Torr · 1 / sec] and dividing by the differential pressure ΔP [Torr] between the inside and the outside of the film forming space. Was.

From the results in Table 4, it was found that it is preferable to make the pressure difference between the inside and outside of the film formation space larger than 9 mTorr in order to prevent plasma leakage.

Experimental Example 4 In this experimental example, a method for suppressing abnormal discharge by keeping the pressure outside the film formation space low was used by using the apparatus shown in FIG. The same manufacturing conditions were used except that the pressure outside the film forming chamber was changed variously under the manufacturing conditions shown in Table 3 by interposing such an oil-valve pump and connecting an oil diffusion pump so that the effective pumping speed could be changed. A discharge experiment was performed.
Table 5 shows the results.

From these results, when the pressure in the isolation container outside the film formation space was increased and became substantially equal to the pressure inside the film formation space, abnormal discharge or discharge concentration occurred, and a film having poor adhesion was deposited. Therefore, it was found that it is preferable to maintain the pressure outside the film formation space at 6 mTorr or less in order to prevent the film quality from being deteriorated due to abnormal discharge.

Outline of Experimental Results In the method and apparatus of the present invention, the stability and uniformity of the microwave plasma are determined by, for example, the type and shape of the microwave applicator, the pressure in the deposition chamber during deposition, the microwave power, and the microwave plasma. Since various parameters such as the degree of confinement, the volume and the shape of the discharge space are intricately entangled, it is difficult to find the optimum conditions with only a single parameter.
The following trends and condition ranges were found.

In the method of the present invention, it is desirable that the inner diameter of the film forming space is preferably 60 mmφ to 120 mmφ. In addition, the deposition film is heated to a desired film formation temperature, and a deposited film is formed on the concave curved surface of the band-shaped member that is curved in a columnar shape. Stress can be reduced.

Further, by changing the opening width of the slit so that the pressure difference between the inside and outside of the film formation space is 9 mTorr or more, the leakage of plasma from the film formation space can be prevented. Further, it was found that by setting the pressure outside the film formation space to 6 mTorr or less, it is possible to prevent the film quality of the deposited film from being deteriorated due to abnormal discharge.

Hereinafter, the method and apparatus of the present invention will be described in more detail based on the facts found by the above (experiment).

The point that the method of the present invention is objectively distinguished from the conventional method of forming a deposited film is that the deposition space is formed in a columnar shape, and the sidewall thereof continuously moves, but also functions as a structural material, and
The point is that it also serves as a support for forming a deposited film.

Here, the function as a structural material is a function of physically and chemically isolating an atmosphere space for film formation, that is, a film formation space and an atmosphere space not involved in film formation. This means, for example, a function of forming atmospheres with different gas compositions and states, restricting the flow direction of gas, and forming atmospheres with different pressure differences.

That is, the band-shaped member is curved to form a side wall of a columnar film-forming space, and from either one of the opposite end surfaces,
By supplying a source gas for forming a deposited film and microwave power into the film forming space and exhausting the gas through a gap left in a part of the side wall, plasma is confined in the film forming space, and the side wall is formed. A functional deposited film is formed on the belt-shaped member constituting the belt-shaped member, and the belt-shaped member itself plays an important function as a structural material for isolating the film-forming space from an external atmosphere space not involved in film-forming. In addition, it can be used as a support for forming a deposited film.

Therefore, the atmosphere outside the film forming space configured with the strip-shaped member as a side wall is completely different from the inside of the film forming space in the gas composition, its state, pressure, and the like.

On the other hand, in the conventional method for forming a deposited film, a support for forming a deposited film is disposed in a film forming space for forming a deposited film, and is exclusively formed in the film forming space. It functions only as a member on which the precursor is deposited, and does not function as a structural material constituting the film forming space as in the method of the present invention.

Further, in the conventional method such as RF plasma CVD, sputtering, etc., the support for forming the deposited film may also serve as an electrode for generating and maintaining discharge, but the plasma confinement is insufficient, The isolation from the external atmosphere space that is not involved in film formation is insufficient, and it cannot be said that it functions as a structural material.

In short, the method of the present invention uses a band-like member capable of functioning as a support for forming a functional deposited film as a side wall of the film-forming space, exhibits a function as the structural material, and forms a film on the band-like member. This also enables continuous formation of a functional deposition film.

According to the results of studies conducted by the present inventors through experiments, any apparatus currently commercially available as a plasma CVD apparatus can be used in any of the apparatuses using RF or microwave in the film forming chamber. The rate at which the source gas for film formation is deposited on the substrate to form a deposited film that can be practically used is at most
At around 15%, the recovery as a deposited film is actually quite low.

The present inventors have conducted repeated studies on the assumption that this point greatly depends on the shape and structure of the film formation space. It was found that by forming a deposited film thereon, the recovery rate was significantly improved. That is, the band-shaped member is used as a base, and while the band-shaped member is continuously moved, the film-shaped side wall is formed by the band-shaped member. A gap is provided in a part of the side wall to exhaust the inside of the film formation chamber. The shape of the film forming chamber is preferably columnar, more preferably cylindrical. Then, in order to improve the recovery rate as a deposited film, it is preferable to increase the ratio of the area of the side wall portion constituted by the band-shaped member to the total area of the wall surface forming the film forming space. That is, as a specific shape of the columnar film-forming space formed by the belt-like member, the ratio of the length of the side wall (the width of the belt-like member) to the inner diameter of the opposite end surfaces is set as much as possible. It is desirable to make it larger. By doing so, a desired functional deposition film can be formed on the inner wall surface of the side wall at a high recovery rate.

In the method of the present invention, when the deposited film formed on the substrate is taken out to the atmosphere, in order to prevent the deposited film from peeling off from the substrate due to the influence of temperature difference or humidity from the time of film formation, After bending the band-shaped member substantially into a column shape and applying a mechanical compressive stress in advance, forming a deposited film at a desired film forming temperature on the concave curved surface of the column-shaped band-shaped member, the band-shaped member is It is gradually cooled to room temperature while developing a flat or deposited film so that the side on which the deposited film is formed is convex and converting mechanical compression stress applied in advance into mechanical tensile stress. At this time, the strip member and the deposited film are formed. The method of relaxing the thermal compressive stress generated by the difference in expansion coefficient with the mechanical tensile stress is preferably used.

By using a material having a linear expansion coefficient larger than that of the deposited film as the material of the belt-shaped member, the above-described method of relaxing stress can be achieved.

Conventionally, in order to avoid the peeling of the deposited film, measures have been taken from the viewpoint of strengthening the adhesion between the substrate and the deposited film. However, this kind of measure is limited to the case where the strength of the substrate is stronger than a certain level. Therefore, for a substrate using a relatively soft material such as polyimide or PET (polyethylene terephthalate), it is difficult to say that the above-described measure alone is a sufficient measure since the base is wrinkled. Therefore, stress relaxation can be an important measure in addition to strengthening the adhesion.

In particular, in the case of a solar cell element manufactured by laminating a plurality of deposited films, since the compressive stress may be amplified by laminating the deposited films, the above-described method of the present invention is important. is there.

In the method of the present invention, in order to efficiently generate and maintain the plasma, the impedance of the microwave is changed according to the complex dielectric constant of the plasma, and the inner diameter of the equivalent outer conductor of the coaxial line including the plasma inside the film formation space. The outer diameter of the microwave permeable member is adjusted and selected in advance so that is equal to the inner diameter of the outer conductor of the coaxial line outside the film formation space.

Here, the expression “equivalent” is used because the actual discharge experiment shows that the inner conductor of the outer conductor containing the plasma under the conditions of the type and flow rate of the source gas, the pressure of the film forming chamber, the microwave power, etc. Is changed, and it affects not only the real part of the dielectric constant of the plasma but also the imaginary part, that is, the absorptivity, and causes phase reversal. Therefore, it was found that it was theoretically desired to predict the value of the outer diameter. Therefore, it is certain that the inner diameter of the outer conductor formed by plasma can be confirmed by an experiment as described later.

Conventionally, in a microwave device having an impedance mismatch, that is, a strong reflection surface, another reflection wave having the same intensity as the reflection wave generated at the reflection surface and having a phase inverted from that of the reflection wave is obtained by a tuner. In this method, these two reflected waves are canceled out by interference to match the impedance.However, even when the reflected waves are apparently canceled out and matched, the reflection surface and the reflection surface are not affected. A large standing wave is generated between the tuner and a large joule heat loss.

Therefore, in order to eliminate this Joule heat loss, the distance between the reflecting surface and the tuner should be made as close as possible, and preferably equal. That is, in the microwave antenna means of the present invention, before the start of the discharge, the dielectric constant of the inside of the film forming chamber and the outside of the film forming chamber are both 1 and the inner diameter of the outer conductor of the coaxial line is inner. Because it ’s getting bigger,
Although it is difficult to match the impedance at the interface between the film forming chambers, the plasma inside the film forming chamber is filled with plasma having a dielectric constant of 1 after discharge starts, and the equivalent inner diameter becomes smaller, and the microwave becomes smaller. If the outer diameter of the transmissive member is appropriately selected, the inner diameter of the outer conductor of the coaxial line inside and outside the film forming chamber can be matched and matched. Thus, it is possible to match the impedance after discharge.

In the method of the present invention, the gas composition and the state outside the film formation space are set in the film formation space so that a film formation space is formed by the strip-shaped member and a deposited film is formed only in the film formation space. Condition is set to be different from For example,
The gas composition outside the film formation space may be a gas atmosphere not directly involved in the formation of a deposited film, or may be an atmosphere containing a source gas discharged from the film formation space. Further, it is needless to say that plasma is confined in the film formation space, but that the plasma and microwave are not leaked outside the film formation space and that abnormal discharge is suppressed. It is also effective in improving the stability and reproducibility of plasma and preventing film deposition on unnecessary portions.

Further, in the apparatus of FIG. 1, since microwave power is supplied in the TEM mode, while the width of the opening is narrow, microwave leakage is automatically suppressed due to the mode,
When the width of the opening is about half the wavelength of the microwave, it is necessary to provide a means for preventing microwave leakage. That is, a conductive punching board or the like having a hole diameter of about 1/20 of the wavelength of the microwave as shown in FIG. 6 may be provided in the gap formed in the longitudinal direction of the belt-shaped member.

In the method of the present invention, the pressure outside the deposition space is set to 6 mTorr
As an alternative to providing the same effect as that described below, the abnormal discharge may be suppressed by flowing a gas (such as He or H ₂ ) having a small ionization cross section outside the film formation space. Needless to say, the gas having a small ionization cross-sectional area may be simultaneously supplied while the pressure outside the film formation space is maintained at 6 mTorr or less.

That is, in the method of the present invention, the plasma is confined in the film formation space, and the abnormal discharge is suppressed outside the film formation space, thereby improving the recovery rate of the source gas for forming the film formation and increasing the film formation speed. And the production of solar cells on an industrial scale can be made possible.

In the method of the present invention, in order to form a deposited film having a uniform thickness and quality over a large area, the microwave antenna means is formed so as to be parallel to the belt-like member constituting the side wall of the film forming space. Microwave power is injected into the film-forming space through microwave antenna means for radiating microwaves in all directions perpendicular to the direction in which microwaves travel, such as a coaxial line or a Lisitano coil, to penetrate into the film space. This is done by creating a plasma. Further, in order to maintain the discharge at a constant plasma density for a long time, the microwave transmitting member may surround the microwave antenna means and be completely isolated from the plasma.

In the method of the present invention, the microwave antenna means is disposed so as to be parallel to the band-shaped member, the distance between the band-shaped member and the microwave antenna means is relatively short, and even in the longitudinal direction of the antenna. It is desirable that the distance be kept equal. With this configuration, the antenna means for supplying microwave power substantially uniformly is provided in the width direction of the belt-shaped member constituting the side wall, so that the plasma density distribution is made uniform.

In particular, in the case of a coaxial line in which the center conductor is isolated from the plasma by the microwave transmitting member described above, increasing the microwave power applied to the inside of the film formation space via the coaxial line increases the inside of the film formation space. There is a threshold at which the microwave power absorbed by the plasma is saturated depending on the type of gas introduced into the plasma and converted into plasma by the microwave power and the gas flow rate. Therefore, the larger the microwave power applied to the inside of the film formation space, the larger the region where the absorption power is saturated. It is injected into the inside, and the plasma density is made uniform, that is, the film thickness and film quality are made uniform over a large area.

However, when such a large amount of microwave power is applied to the inside of the film formation space, the electrical characteristics of the deposited film formed are degraded, heat is generated inside the microwave permeable member, The member may be damaged by the temperature rise caused by being exposed to the plasma, and the microwave power that can be input into the above-mentioned film formation space may be limited.

In such a case, since the microwave power supplied to the film forming space is restricted, the above-described saturation of the absorbed power does not occur and the plasma density does not become uniform. That is, since the microwave power supplied from the microwave antenna means disposed inside the film formation space to the inside of the film formation space gradually decreases in the direction in which the microwave travels, the plasma density becomes spatially non-uniform. Distribution.

In order to avoid this and form a deposited film having a uniform film thickness and quality over a large area, the microwave power applied to the inside of the film formation space along the traveling direction of the microwave causes the microwave to travel. A truncated conical or conical-shaped microwave permeable member having an inner diameter gradually increased so as to compensate for the decay along the direction is provided, and the distance between the band-shaped substrate and the microwave antenna means described above is increased. What is necessary is just to make it narrow along the traveling direction of a microwave.

As described above, the method of the present invention enables the formation of a deposited film having a uniform thickness and quality over a large area regardless of the magnitude of the microwave power to be supplied.

In the method of the present invention, it is preferable that an inner wall surface of the film forming space has conductivity necessary for a bias current having a desired current density to flow. For this purpose, first, it is preferable that the belt-like member is made of a conductive material, but it is necessary that at least a surface facing the film formation space be subjected to a conductive treatment.

In the method of the present invention, when each of at least two or more kinds of deposition film forming source gases having different compositions is separately introduced into the film formation space from a plurality of gas supply units,
Preferably, the source gas for forming a deposited film discharged from the gas supply means is uniformly discharged in the width direction of the band-shaped member, and is discharged in one direction toward the band-shaped member close to the gas supply means. I do. That is, the gas discharge ports opened in each of the gas supply means are directed to different directions so that the respective material gases for forming the deposited film having different compositions do not mix with each other immediately after being discharged from the gas supply means. It is desirable.

The gas supply means is arranged in parallel with the belt-like member constituting the side wall.

The number of the gas supply means used in the method of the present invention is preferably at least equal to or greater than the number of component elements of the functional deposition film to be formed. By appropriately changing the composition of the film-forming source gas, a functional deposition film whose composition is controlled can be formed.

It is preferable that each of the gas supply means is disposed so as to be contained in the columnar film-forming space so that the discharged deposition film forming material gas is surely excited and decomposed. Also,
In order to give a desired composition distribution to the deposited film to be formed, it is desirable to appropriately adjust the arrangement of the gas supply means. Further, a rectifying plate may be provided in the columnar film forming space in order to adjust and control the flow path of the source gas for forming a deposited film in the columnar film forming space.

Examples of the composition-controlled functional deposition film formed by the method of the present invention include SiGe, SiC, GeC, SiSn, GeSn, and SnC.
Group IV alloy semiconductor thin film, so-called II such as GaAs, GaP, GaSb, InP, InAs
Group IV compound semiconductor thin film, ZnSe, ZnS, ZnTe, CdS, CdSe, CdTe
So-called II-VI compound semiconductor thin film, CuAlS ₂ , CuAlSe ₂ , CuAl
Te ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , CuGaS ₂ , CuGaSe ₂ , CuGaTe, A
gInSe ₂ , AgInTe ₂ etc. so-called I-III-VI compound semiconductor thin film, Zn
So-called II-IV-V compound semiconductor thin films such as SiP ₂ , ZnGeAs ₂ , CdSiAs ₂ , CdSnP ₂ , Cu ₂ O, TiO ₂ , In ₂ O ₃ , SnO ₂ , ZnO, CdO, Bi ₂ O ₃ , CdSnO
₄ Hitoshisho called oxide semiconductor thin film, and may be mentioned those which contains a valence electron controlling element to valence electron control these semiconductor. Further, there may be mentioned a material in which a valence electron controlling element is contained in a so-called group IV semiconductor thin film such as Si, Ge and C. Of course, amorphous semiconductors such as A-Si; H and A-Si: H: F may have different contents of hydrogen and / or fluorine.

By controlling the composition of the semiconductor thin film, forbidden band width control, valence electron control, refractive index control, crystal control, and the like are performed. By forming a functional deposition film whose composition is controlled in the vertical or horizontal direction on the belt-like member, a large-area thin-film semiconductor device having excellent electrical, optical, and mechanical properties can be manufactured. .

That is, by changing the forbidden band width and / or the valence electron density in the vertical direction of the deposited semiconductor layer, the carrier traveling property is enhanced, and the carrier recombination at the semiconductor interface is prevented, so that the electrical characteristics are improved. Is improved. In addition, by continuously changing the refractive index to form an optically non-reflective surface, the light transmittance into the semiconductor layer can be improved. Further, by changing the hydrogen content or the like, a structural change is applied to alleviate stress, so that a deposited film having high adhesion to a substrate can be formed.

Further, by forming semiconductor layers having different crystallinities in the lateral direction, for example, a photoelectric conversion element formed of an amorphous semiconductor and a switching element formed of a crystalline semiconductor are simultaneously formed continuously on the same substrate. I can do it.

In the present invention, the deposition film forming source gas used for forming the above-mentioned functional deposition film is appropriately adjusted in its mixing ratio in accordance with the structure of the desired functional deposition film, and is used in the deposition space. To be introduced. Although a plurality of gas supply means are used for the introduction, the composition of the deposited film forming source gas introduced from each gas supply means may be different, or may be the same depending on the purpose. Further, the composition may be changed continuously over time.

In the present invention, a compound containing a Group IV element of the periodic table, which is preferably used for forming a Group IV semiconductor or a Group IV alloy semiconductor thin film, includes Si, Ge, C, Sn, and Pb atoms. Compounds, specifically, SiH ₄ , Si
_{2 H 6, Si 3 H 8} , Si 3 H 6, Si 4 H 8, Si 5 H silane compounds such as _{10, SiF 4, (SiF 2} ) 5, (SiF 2) 6, (SiF 2) 4, Si ₂ F ₆ , Si
_{3 F 8, SiHF 3, SiH} 2 F 2, Si 2 H 2 F 4, Si 2 H 3 F 3, SiCl 4, (SiCl
_{2) 5, SiBr 4, (} SiBr 2) 5, Si 2 Cl 6, Si 2 Br 6, SiHCl 3, SiHB
_{r 3, SiHI 3, Si 2} Cl halogenated silane compounds such as ₃ F _3, GeH
_4, Ge ₂ H germane compounds such as _{6, GeF 4, (GeF 2} ) 5, (Ge
F ₂ ) ₆ , (GeF ₂ ) ₄ , Ge ₂ F ₆ , Ge ₃ F ₈ , GeHF ₃ , GeH ₂ F ₂ , Ge ₂ H ₂ F
_{4, Ge 2 H 3 F 3} , GeCl 4, (GeCl 2) 5, GeBr 4, (GeBr 2) 5, Ge 2 C
l ₆ , Ge ₂ Br ₆ , GeHCl ₃ , GeHBr ₃ , GeHI ₃ , germanium halide compounds such as Ge ₂ Cl ₃ F ₃ , CH ₄ , C ₂ H ₆ , methane series hydrocarbon gas such as C ₃ H ₈ , Ethylene hydrocarbon gas such as C ₂ H ₄ and C ₃ H ₆ , cyclic hydrocarbon gas such as C ₆ H ₆ , CF ₄ , (CF ₂ ) ₅ , (CF
₂ ) ₆ , (CF ₂ ) ₄ , C ₂ F ₆ , C ₃ F ₈ , CHF ₃ , CH ₂ F ₂ , CCl ₄ , (CCl ₂ )
_{5, CBr 4, (CBr 2} ) 5, C 2 Cl 6, C 2 Br 6, CHCl 3, CHI 3, C 2 Cl 3
Halogenated carbon compounds such as _{F 3, SnH 4, Sn (} CH 3) tin compounds such as _{4, Pb (CH 3) 4} , Pb (C 2 H 5) Lead compounds such ₆ and the like. These compounds may be used alone or in combination of two or more.

In the present invention, desired composition control is performed by appropriately mixing and using these compounds.

Group IV semiconductors formed in the present invention, or as a valence electron controlling agent used for controlling the valence electrons of the group IV alloy semiconductor, as a p-type impurity, a group III element of the periodic table, for example, B, Preferred examples include Al, Ga, In, Tl, and the like, and examples of the n-type impurities include elements belonging to Group V of the periodic table, such as N, P, As, Sb, and Bi. Particularly, B, Ga, P, Sb and the like are most suitable. The amount of the impurity to be doped is appropriately determined according to desired electrical and optical characteristics.

As such a raw material for introducing impurities, a material that is in a gas state at normal temperature and normal pressure or that can be easily gasified at least under film forming conditions is employed. As the starting material for introducing such impurities, specifically, PH ₃ , P ₂ H ₄ , PF ₃ , P
_{F 5, PCl 3, AsH 3} , AsF 3, AsF 5, AsCl 3, SbH 3, SbF 5, BiH
_{3, BF 3, BCl 3,} BBr 3, B 2 H 6, B 4 H 10, B 5 H 9, B 5 H 11, B 6 H
₁₀ , B ₆ H ₁₂ and AlCl ₃ . The compounds containing the above impurity elements may be used alone or in combination of two or more.

In the present invention, the compound containing a Group II element of the periodic table, which is used for forming a Group II, VI compound semiconductor, specifically, Zn (CH ₃ ) ₂ , Zn (C ₂ H ₅ ) ₂ , Zn (OCH ₃ ) ₂ , Zn (O
_{C 2 H 5) 2, Cd} (CH 3) 2, Cd (C 2 H 5) 2, Cd (C 3 H 7) 2, Cd (C
_{4 H 9) 2, Hg (} CH 3) 2, Hg (C 2 H 5) 2, Hg (C 6 H 5) 2, Hg [C = (C
₆ H ₅ )] _{2 and the} like. Compounds containing Group VI elements of the periodic table include, specifically, NO, N ₂ O, CO ₂ , CO, H _{2
S, SCl 2, S 2 Cl} 2, SOCl 2, SeH 2, SeCl 2, Se 2 Br 2, Se (C
_{H 3) 2, Se (C} 2 H 5) 2, TeH 2, Te (CH 3) 2, Te (C 2 H 5) 2 and the like.

Of course, these raw materials can be used alone or in combination of two or more.

As the valence electron controlling agent used for controlling the valence electrons of the II-VI group compound semiconductor formed in the present invention, compounds containing elements of the periodic table I, III, IV, V group and the like are effective. Can be mentioned.

Specifically, compounds containing a Group I element include LiC ₃ H ₇ ,
Preferred examples include Li (sec-C ₄ H ₉ ), Li ₂ S, and Li ₃ N.

Compounds containing Group III elements include BX ₃ , B ₂ H ₆ ,
_{B 4 H 10, B 5 H} 9, B 5 H 11, B 6 H 10, B (CH 3) 3, B (C 2 H 5) 3, B 6 H
_{12, AlX 3, Al (CH} 3) 2 Cl, Al (CH 3) 3, Al (OCH 3) 3, Al (CH 3)
_{Cl 2, Al (C 2 H} 5) 3, Al (OC 2 H 5) 3, Al (CH 3) 3 Cl 3, Al (iC
_{4 H 9) 3, Al (} iC 3 H 7) 3, Al (C 3 H 7) 3, Al (OC 4 H 9) 3, GaX 3, G
a (OCH ₃ ) ₃ , Ga (OC ₂ H ₅ ) ₃ , Ga (OC ₃ H ₇ ) ₃ , Ga (OC ₄ H ₉ ) ₃ , Ga (C
_{H 3) 3, Ga 2 H} 6, GaH (C 2 H 5) 2, Ga (OC 2 H 5) (C 2 H 5) 2, In (CH 3)
₃ , In (C ₃ H ₇ ) ₃ , In (C ₄ H ₉ ) ₃ , and NH ₃ , HN ₃ , N ₂ H ₅ N ₃ , N ₂ H ₄ , NH ₄ N ₃ , PX ₃ , P (OCH ₃ ) ₃ ,
P (OC ₂ H ₅ ) ₃ , P (C ₃ H ₇ ) ₃ , P (OC ₄ H ₉ ) ₃ , P (CH ₃ ) ₃ , P (C
_{2 H 5) 3, P (} C 3 H 7) 3, P (C 4 H 9) 3, P (OCH 3) 3, P (OC 2 H 5) 3, P
(OC ₃ H ₇ ) ₃ , P (OC ₄ H ₉ ) ₃ , P (SCN) ₃ , P ₂ H ₄ , PH ₃ , AsH ₃ , AsX
_{3, As (OCH 3) 3} , As (OC 2 H 5) 3, As (OC 3 H 7) 3, As (OC 4 H 9) 3,
_{As (CH 3) 3, As} (CH 3) 3, As (C 2 H 5) 3, As (C 6 H 3) 3, SbX 3, Sb
_{(OCH 3) 3, Sb (} OC 2 H 5) 3, Sb (OC 3 H 7) 3, Sb (OC 4 H 9) 3, Sb (CH
₃ ) ₃ , Sb (C ₃ H ₇ ) ₃ , Sb (C ₄ H ₉ ) _{3 and the} like.

In the above, X represents a halogen (F, Cl, Br, I).

Of course, these raw materials may be one kind,
Species or more may be used in combination.

Further, as the compound containing a group IV element, the compounds described above can be used.

Specific examples of the compound containing a Group III element of the periodic table used for forming a Group III-V compound semiconductor in the present invention include BX ₃ (where X represents a halogen atom) and B ₂ H. _{6, B 4 H 10, B} 5 H 9, B 5 H 11, B 6 H 10, B 6 H 12, Al
X ₃ (where X represents a halogen atom), Al (CH ₃ ) ₂ Cl,
Al (CH ₃ ) ₃ , Al (OCH ₃ ) ₃ , Al (CH ₃ ) Cl ₂ , Al (C ₂ H ₅ ) ₃ , Al (OC _{2
H 5) 3, Al (CH} 3) 3 Cl 3, Al (iC 4 H 9) 3, Al (iC 3 H 7) 3, Al (C 3
H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , GaX ₃ (where X represents a halogen atom), Ga (OCH ₃ ) ₃ , Ga (OC ₂ H ₅ ) ₃ , Ga (OC ₃ H ₇ ) ₃ , Ga (OC ₄ H
_{9) 3, Ga (CH 3} ) 3, Ga 2 H 6, GaH (C 2 H 5) 2, Ga (OC 2 H 5) (C
_{2 H 5) 2, In (} CH 3) 3, In (C 3 H 7) 3, In (C 4 H 9) 3 and the like. As the compound containing a Group V element of the periodic table, specifically, NH ₃ , HN ₃ , N ₂ H ₅ N ₃ , N ₂ H ₄ , NH ₄ N ₃ , PX ₃ (however,
X represents a halogen atom. ), P (OCH ₃ ) ₃ , P (OC ₂ H ₅ ) ₃ , P
_{(C 3 H 7) 3,} P (OC 4 H 9) 3, P (CH 3) 3, P (C 2 H 5) 3, P (C 3 H 7) 3, P
(C ₄ H ₉ ) ₃ , P (OCH ₃ ) ₃ , P (OC ₂ H ₅ ) ₃ , P (OC ₃ H ₇ ) ₃ , P (OC
_{4 H 9) 3, P (} SCN) 3, P 2 H 4, PH 3, AsX 3 ( where, X is a halogen _{atom.), AsH 3, As (} OCH 3) 3, As (OC 2 H 5 ) ₃ , As
(OC ₃ H ₇ ) ₃ , As (OC ₄ H ₉ ) ₃ , As (CH ₃ ) ₃ , As (CH ₃ ) ₃ , As (C ₂ H ₅ )
₃ , As (C ₆ H ₅ ) ₃ , SbX ₃ (where X represents a halogen atom), Sb (OCH ₃ ) ₃ , Sb (OC ₂ H ₅ ) ₃ , Sb (OC ₃ H ₇ ) ₃ , Sb (OC ₄ H
₉ ) ₃ , Sb (CH ₃ ) ₃ , Sb (C ₃ H ₇ ) ₃ , Sb (C ₄ H ₉ ) _{3 and the} like. [However, X is a halogen atom, specifically, F, Cl,
Represents at least one selected from Br and I. Of course, these raw materials can be used alone or in combination of two or more.

As the valence electron controlling agent used for controlling the valence electrons of the group III-V compound semiconductor formed in the present invention, compounds containing elements of the periodic table II, IV, VI group and the like are mentioned as effective ones. Can be.

Specifically, as a compound containing a group II element, Zn (C
_{H 3) 2, Zn (C} 2 H 5) 2, Zn (OCH 3) 2, Zn (OC 2 H 5) 2, Cd (CH 3) 2,
Cd (C ₂ H ₅ ) ₂ , Cd (C ₃ H ₇ ) ₂ , Cd (C ₄ H ₉ ) ₂ , Hg (CH ₃ ) ₂ , Hg (C
₂ H ₅ ) ₂ , Hg (C ₆ H ₅ ) ₂ , Hg [C = (C ₆ H ₅ )] _{2 and the} like. Examples of the compound containing a Group VI element include NO, N ₂ O, C
_{O 2, CO, H 2 S} , SCl 2, S 2 Cl 2, SOCl 2, SeH 2, SeCl 2, Se 2 B
r ₂ , Se (CH ₃ ) ₂ , Se (C ₂ H ₅ ) ₂ , TeH ₂ , Te (CH ₃ ) ₂ , Te (C ₂ H ₅ ) ₂
And the like.

Of course, these raw materials may be one kind,
Species or more may be used in combination.

Further, examples of the compound containing a group IV element include the compounds described above.

The raw material compounds described above in the present invention are He, Ne, Ar, K
It may be introduced as a mixture with a rare gas such as r, Xe, and Rn, and a diluent gas such as H ₂ , HF, and HCl.

These diluent gases and the like may be independently introduced from gas supply means.

In the method of the present invention, in order to uniformly and stably generate and maintain plasma in the columnar film-forming space, the shape and volume of the film-forming space and the type of source gas introduced into the film-forming space And the flow rate, the pressure in the film-forming space, the amount of micro-flow power supplied into the film-forming space, and the matching of microwaves, etc., respectively, but these parameters are organically connected to each other. However, the conditions are not necessarily defined, and it is desirable to set preferable conditions as appropriate.

 Hereinafter, the device of the present invention will be described in more detail.

In the apparatus of the present invention, when the band-shaped member functions as a structural material, the outside of the film formation chamber may be air, but a functional deposition film formed by the inflow of air into the film formation chamber. In this case, an appropriate air inflow prevention means may be provided. Specifically, a mechanical sealing structure using an O-ring, a gasket, a helicopter, a magnetic fluid, or the like, or a diluent gas atmosphere that has little or no effect on the characteristics of the deposited film to be formed, Alternatively, it is desirable to provide a separation container for forming an appropriate vacuum atmosphere around the periphery. In the case of the mechanical sealing structure, special care needs to be taken so that the sealing state can be maintained while the belt-shaped member moves continuously.
In the case where the apparatus of the present invention is connected to a plurality of other deposited film forming apparatuses and a deposited film is continuously stacked on the belt-shaped member, it is preferable that the apparatuses be connected using gas gate means or the like. In the case where only a plurality of the apparatuses of the present invention are connected, the film forming chamber is an independent film forming atmosphere in each apparatus. Therefore, the isolation container may be single or may be provided in each apparatus. good.

In the apparatus of the present invention, the pressure outside the film forming chamber may be in a depressurized state or a pressurized state. However, when the band-shaped member is greatly deformed by a pressure difference from the film forming chamber, an appropriate auxiliary structure is used. What is necessary is just to arrange a material.

As the auxiliary structure material, it is desirable that the shape substantially the same as the side wall of the film forming chamber is formed of a wire, a thin plate, or the like made of metal, ceramics, reinforced resin, or the like having appropriate strength. In addition, since the contact portion of the band-shaped member that contacts and supports the surface of the auxiliary structure material that is not exposed to the microwave plasma substantially forms a shadow of the auxiliary structure material, formation of a deposited film is almost impossible. Not done. Therefore, it is desirable to design the projection area of the auxiliary structural member on the belt-shaped member so as to be as small as possible.

In addition, the auxiliary structural member is brought into close contact with the band-shaped member, and is rotated or moved in synchronization with the transport speed of the band-shaped member, so that the mesh provided on the auxiliary structural member is moved.
A pattern or the like can be formed on the band-shaped member.

First, as for the material of the band-shaped member to be used in the apparatus of the present invention, a material having flexibility capable of continuously bending the band-shaped member is used, and the bending start end, the bending end end, and the middle curved portion are smooth. It is desirable to form a shape. Further, it is preferable that the belt-like member has such a strength that it is unlikely to be bent or twisted when being continuously transported.

Specifically, metal thin plates and their composites such as stainless steel, aluminum and its alloys, iron and its alloys, copper and its alloys, and metal thin films of different materials are sputtered, vapor-deposited, plated on their surfaces. Surface coated by a method or the like. In addition, heat-resistant resin sheets such as polyimide, polyamide, polyethylene terephthalate, epoxy or the like and glass fiber, carbon fiber, boron fiber, metal fiber or the like on the surface of a composite of metal alone or alloy, and transparent conductive oxide (TC
O) and the like, which have been subjected to a conductive treatment by a method such as plating, vapor deposition, spatter, coating or the like. In addition, a strip-shaped member having the above-described configuration in which an insulating thin film such as SiO ₂ , Si ₂ N ₄ , Al ₂ O ₃ , AlN, and the above-described heat-resistant resin is partially formed on the conductive treated surface is used. You can also.

As long as the thickness of the band-shaped member is within a range that exhibits a strength that maintains a curved shape formed at the time of conveyance by the conveyance means, the thickness is preferably as thin as possible in consideration of cost, storage space, and the like. Is desirable.

However, in the apparatus of the present invention, as shown in FIG. 3, the bending portion end surface support ring 308 is disposed one by one in the left and right opposition to the extent that it slightly contacts the peripheral portion of the band-shaped member. Since the member is transported, it is necessary to increase the strength of the band-shaped member so that the band-shaped member does not sag between the pair of opposed curved surface end surface support rings.

Also, for the above-mentioned stress relaxation of the deposited film, it is preferable that the band-shaped member is thick. Therefore, the thickness of the band-shaped member is appropriately determined in view of these points, but slightly varies depending on the kind of the material of the band-shaped member and the curvature of its bending. For example, when the belt-like member is made of stainless steel, its thickness is about 0.03 to 0.3 mm. Similarly, the thickness is about 0.05 to 0.5 mm for aluminum or copper, and about 0.1 to 3 mm for synthetic resin.

When the band-shaped member is used as a substrate for a solar cell, when the band-shaped member is electrically conductive such as a metal, the band-shaped member may be directly used as an electrode for extracting current, or is electrically insulating such as a synthetic resin. In the case, Al, Ag, Pt, Au, Ni, Ti, Mo, W, Fe, V, Cr, Cu,
Stainless steel, brass, nichrome, SnO ₂ , In ₂ O ₃ , ZnO,
A so-called simple metal or alloy such as SnO ₂ -In ₂ O ₃ (ITO) and a transparent conductive oxide (TCO) are subjected to surface treatment in advance by plating, vapor deposition, spattering, etc. to form electrodes for current extraction. It is desirable to keep. In addition, an insulating film may be partially formed for the purpose of facilitating the element isolation process.

Of course, even if the strip-shaped member is made of an electrically conductive material such as metal, it is possible to improve the reflectance of long-wavelength light on the substrate surface or to interdiffuse constituent elements between the substrate material and the deposited film. A different kind of metal layer or the like may be provided on the side of the substrate on which the deposited film is formed, for the purpose of preventing the occurrence of a short circuit or forming an interference layer for preventing a short circuit. When the band-shaped member is relatively transparent and a solar cell having a layer configuration in which light is incident from the side of the band-shaped member, a conductive thin film such as the transparent conductive oxide or a metal thin film is previously deposited. It is desirable to form it.

Further, the surface property of the belt-shaped member may be a so-called smooth surface or a fine uneven surface. In the case of a minute uneven surface, the uneven shape is spherical, conical, pyramidal, or the like, and the maximum height (Rmax) is preferably 50.
By setting the angle between 0 ° and 5000 °, light reflection on the surface becomes irregular reflection, and the optical path length of light reflected on the surface is increased.

In the apparatus of the present invention, it is preferable to insert a substrate cover that covers a part of the side wall in order to control the thickness of the film deposited in the film forming chamber.

It is desirable that the center conductor used in the device of the present invention be made of a metal member having a small ohmic loss. More specifically, it may be made of silver, copper, aluminum, or the like, or any of these metals plated on a central conductor made of another material. In this apparatus, a silver-plated stainless steel tube was used.

In addition, the center conductor protruding into the film formation chamber is separated from the plasma by a microwave permeable member,
A deposited film is formed on the center conductor, which serves as a microwave absorber, thereby avoiding a decrease in microwave power input efficiency.

In the film forming chamber, a wall surface facing the surface into which the center conductor is inserted is formed of a microwave reflecting member,
On the other hand, the surface into which the central conductor is inserted is constituted by a member that transmits microwaves and simultaneously maintains the airtightness between the inside and the outside of the film forming chamber, a microwave, and a reflecting member. Since it is composed of a band-shaped member, a resonator structure can be obtained by appropriately selecting the width of the band-shaped member.

As is well known, an electromagnetic wave is strongly reflected on a boundary surface and a short-circuit surface where the impedance of the line changes suddenly.
Here, the opposite end faces of the above-mentioned film forming chamber strongly reflect microwaves corresponding to the short-circuited surfaces with the above-mentioned boundary faces, respectively, and electromagnetic waves are injected into a cavity in which two strong anti-slopes are appropriately arranged. Then, a resonator structure having a high Q value can be formed.

In the apparatus of the present invention, a resonator structure may be configured by moving both opposing end faces of the film forming chamber, but a semi-coaxial resonator structure is formed by the center conductor insertion length adjusting mechanism, which is more excellent in operability. Alternatively, the resonator length may be equivalently varied, that is, the impedance may be adjusted by inserting a microwave permeable high dielectric member at a desired position in the film forming chamber.

If the resonator structure is adjusted in advance before the discharge as described above, the discharge can be easily started by the power storage effect of the resonator structure, and the impedance can be matched by the center conductor insertion length adjusting mechanism described above after the discharge. For example, a constant discharge state can be constantly maintained for a long time in a wide film formation pressure range.

As a microwave transparent member used in the apparatus of the present invention, for example, a dielectric tube indicated by 103 in FIG. 1 can be mentioned.

As a material of the dielectric tube, any material having a small dielectric loss tanδ (tan delta) in a microwave band to be used may be used, but if the thermal conductivity is high and the thermal shock is strong, a film adhered to the dielectric tube may be used. It is even better because it suppresses the deterioration and increase of the reflection and absorption of the microwave power and prevents the dielectric tube from being thermally damaged. Beryllia, alumina / ceramics, boron nitride, quartz, etc. are suitable as the material most suitable for such conditions.
Ceramics are most preferred.

In order to generate a microwave glow discharge and stably and stably discharge the dielectric tube, a function of transmitting microwaves to the dielectric tube and maintaining airtightness is required. As the shape of the dielectric tube that fulfills this function, any of the following two methods is optimal. That is, an open-end cylindrical pipe in which one perforated flange is welded to each end of an open cylindrical pipe, or a closed-end cylindrical pipe in which a perforated flange is welded to the open end side of a cylindrical pipe having one closed end. Is one of The flange portion may be disposed so as to be in close contact with one wall of the opposed end face of the film forming chamber via the O-ring so that airtightness can be maintained. From the viewpoint of maintenance and inspection, the latter closed-end cylindrical tube is more advantageous.

The microwave-permeable high-permittivity member used in the device of the present invention may be alumina ceramics, beryllia,
It is made of a material such as boron nitride, and is disposed inside or at the end of the semi-coaxial resonator structure formed by the above-mentioned center conductor insertion length adjusting mechanism, thereby effectively changing the resonator length. It was confirmed by the present inventors that it was obtained. As a result of further studies by the present inventors, it has been found that the optimum dimension of the microwave permeable high dielectric constant member has a correlation with the insertion length of the center conductor. Therefore, using the HP8757A Scalar Network Analyzer (manufactured by Hewlett-Packard Co.) with the insertion length of the center conductor fixed, the microwave permeable high dielectric chamber is adjusted so that the resonance frequency becomes 2.45 GHz. What is necessary is just to determine the shape of a member.

Regarding the means for supporting and transporting the belt-like member used in the apparatus of the present invention, the belt-like member (substrate) forms a side wall of the film forming chamber, and thus the belt-like member being transported is twisted, bent, If meandering or the like occurs, the discharge becomes unstable, and it becomes difficult to produce a large amount of films of the same quality with good reproducibility. Also, if dirt or dust adheres to the surface of the means for supporting and transporting the belt-shaped member, it often causes a defect in the deposited film formed thereon, which has been a problem. In other words, the means for supporting and transporting the band-like member prevents the film forming chamber from being deformed, and attaches the band-like member to the surface on which the deposited film of the band-like member is formed (this is abbreviated as “film-forming surface”). It has been found that it is important to minimize contact between the supporting and conveying means.

In other words, in order to prevent the deformation of the film forming chamber at the first point, a known crown mechanism is incorporated in the means for supporting and transporting the belt-shaped member to prevent twisting and meandering, and to prevent deflection by a known tension adjusting mechanism. Can be.

Further, in order to minimize contact of the means for supporting and transporting the band-shaped member with the film forming surface of the second point, the support of the band-shaped member on the film forming surface side is performed only at the peripheral edge of the band-shaped member, and the band-shaped member is supported. The support of the back surface of the film forming surface of the member may be supported and transported over the entire width of the belt-shaped member.

In other words, the one in which the curved portion forming means of the band-shaped member is disposed inside the film forming chamber is a curved portion end surface support ring that contacts and supports only the peripheral portion of the band-shaped member, and is installed outside the film forming chamber. Objects contact the entire width of the strip.
It is a roller to support. In order to support and convey the inside of the band-shaped member by the bending portion end surface support ring, it may be supported by a number of bending portion support inner rings 113 as shown in FIG. 1 or as shown in FIG. As described above, the support may be supported by a pair of curved portion support inner rings 308 having substantially the same size as the opposite end surfaces of the columnar deposition chamber.

Here, in order to form a columnar film-forming chamber having a curved band-like member as a side wall and a gap provided in the longitudinal direction of the above-mentioned band-like member, a continuously conveyed band-like member is formed by a pair of openings. The conveying direction is gently changed by a curving start end forming roller composed of a supporting inner roller and an opening supporting outer roller, and the belt-shaped member is curved by the curving portion end surface supporting ring so as to form a side wall of a film forming chamber. This is achieved by gently changing the transport direction with a curved end-end forming roller composed of a pair of opening-supporting inner rollers and an opening-supporting outer roller.

Here, if the diameter of the opening supporting outer roller is too large, the distance from the central conductor to the belt-shaped member varies depending on the direction, and thus, a large portion of non-uniform plasma density is generated. On the other hand, if the diameter of the opening-portion-supporting outer roller is too small, the belt-shaped member may be left distorted or the film may be peeled off due to bending stress. Therefore, for a metal strip having a thickness of 0.15 mm, a roller having a diameter of 60 mmφ to 100 mφ, a thickness of 0.05 mm
In mm, it is desirable to use a roller having a diameter of about 25 mmφ. Further, in order to immediately end the evacuation after the maintenance, the apparatus may be configured such that an interval between the bending start end forming roller and the bending end end forming roller can be changed. In addition, as a method of supporting and conveying the band-shaped member with the curved portion end surface support ring, only sliding friction may be used, or the band-shaped member may be processed with a sprocket hole or the like, and at the same time, the curved portion end surface support ring may be used. A sprocket may be used.

Also, in the apparatus of the present invention, the surface temperature of the band-shaped member is an important parameter that affects the film quality of the deposited film. However, as shown in FIG. By heating, the belt-shaped member can be heated from the back surface of the film forming surface. However, when the conveying speed of the band-shaped member is slow, that is, when the band-shaped member stays in the film forming chamber for a long time or when the microwave input power is large, the temperature of the band-shaped member rises remarkably, and lamp radiant heating is performed. In some cases, it may not be possible to adjust the temperature with just the above. In such a case, a curved portion supporting outer roller (not shown) is provided in addition to the curved portion supporting inner ring indicated by 308 in FIG. 3 and extends over the entire width of the back surface of the film forming surface of the belt-shaped member. By bringing the curved portion supporting outer roller into pressure contact and incorporating a heat exchange medium inside the curved portion supporting outer roller, both heating and cooling are possible, and the temperature can be adjusted.

It is desirable that the number of gas supply means provided in the apparatus of the present invention is at least equal to or greater than the number of component elements of the functional deposition film to be formed.
Each of the gas supply means is constituted by a pipe-shaped gas introduction pipe, and one or more rows of gas discharge ports are opened on the side surfaces thereof. As the material constituting the gas introduction tube, a material that is not damaged in microwave plasma is preferably used. Specifically, heat-resistant metals such as stainless steel, nickel, titanium, niobium, tantalum, tungsten, vanadium, and milybdenum, and those obtained by subjecting these to thermal spraying on ceramics such as alumina, silicon nitride, and quartz, and alumina, silicon nitride, Examples thereof include ceramics such as quartz and those composed of a composite.

In the apparatus of the present invention, the gas supply means is provided in parallel with a width direction of a band-shaped member constituting a side wall of the film forming chamber, and the gas discharge port is directed to an adjacent band-shaped member.

The arrangement of the gas supply means used in the apparatus of the present invention will be specifically described below with reference to the drawings, but is not particularly limited thereto.

FIG. 4 is a schematic side sectional view showing the arrangement of gas introduction pipes in the apparatus of the present invention. In this drawing, only main constituent members are shown.

The example shown in FIG. 4 is a typical example in which three gas introduction pipes 106a, 106b, and 106c as gas supply means are provided in a columnar film formation chamber 401, and a pipe-shaped gas introduction pipe 106a is provided. ,Ten
6b and 106c are approximately equidistant from the center O of the film forming chamber 401, and the width of the belt-like member 101 at angles of θ ₁ , θ ₂ , and θ ₃ as shown in FIG. It is arranged parallel to the direction. And the gas outlets 402a, 402b, 40
2c are directed to the adjacent strip-shaped members 101, respectively.

In this arrangement, the gas introduction tube 106b is located at the center line H of the film formation chamber 401.
Although it is arranged on H ', it may be arranged at any position shifted to the left or right as desired. Also, the gas introduction pipe 106a,
The distances from the center O of 106b and 106c may be equal or different from each other. The angles θ ₁ , θ ₂ , θ ₃ may again be equal or different.

Raw materials for forming a deposited film, which are appropriately mixed as required, are introduced into each of the gas introduction pipes 106a, 106b, and 106c while being independently controlled.

The gas discharge ports 402a, 402b, and 402c are formed in a line on the side surface of each gas introduction pipe at substantially equal intervals, but according to the increase or decrease in the gas introduction amount, the width of the deposited film formed in the width direction is increased. The intervals may be changed as appropriate to improve the uniformity.

Of course, the number of gas introduction pipes may be two or four or more.

In the apparatus of the present invention, a bias voltage may be applied to the gas introduction pipe in order to control the plasma potential of the microwave plasma generated in the film formation chamber. The bias voltages applied to the plurality of gas introduction tubes may be equal to each other, or may be different from each other. As the bias voltage, it is desirable to apply a DC, a pulsating current, and an AC voltage alone or by superimposing each of them.

In order to effectively apply a bias voltage, it is desirable that the surfaces of both the gas introduction pipe and the belt-shaped member are conductive.

By controlling the plasma potential by applying a bias voltage, it is possible to improve plasma stability, reproducibility, film characteristics, and suppress generation of defects.

(Example of device)

Hereinafter, specific examples of the present invention will be described with reference to the drawings, but the present invention is not limited to these examples.

Apparatus Example 1 FIG. 1 is a perspective view schematically showing a typical example of a film forming chamber and its peripheral mechanism, which is a feature of the present invention and has a moving belt-shaped member as a side wall.

In FIG. 1, 101 is a strip-shaped member, 102 is a central conductor of a coaxial line for supplying microwaves, 103 is a dielectric tube which is a microwave transparent member, 104 is a film forming chamber, 105 is a small hole,
Reference numerals 106a, 106b, and 106c denote gas introduction tubes, respectively, into which a source gas for forming a deposited film is independently introduced via a mass flow controller (not shown).

When a bias voltage for controlling the plasma potential is applied, a voltage may be applied to the gas introduction pipe from a DC or AC power supply or the like via a conducting wire. In that case, it is desirable to take in the insulating joint into a part of the gas introduction pipe and take care that the bias voltage is applied only to the film formation space side. 107 is a vacuum exhaust port, 108 is a belt-shaped member supporting outer roller, 109 is a belt-shaped member supporting inner roller, 110 is a slit-shaped opening of a film forming chamber, 111 is an opening supporting outer roller, 112 is an opening supporting inner roller, 113 Is a curved portion support inner ring.

The two arrows in FIG. 1 indicate the flow of the source gas, respectively.

In FIG. 1, a film forming chamber 104 composed of a belt-like member 101 is shown.
Is a columnar shape, and a central conductor 102 of a coaxial line is disposed on a rotation axis of the film forming chamber.
A dielectric tube 103, which is a microwave transparent member, is disposed coaxially. The film forming chamber 104 includes an opening supporting outer roller 1.
While the belt-shaped member 101 is sandwiched between the roller 11 and the opening support inner roller 112, the transport direction is changed, and a plurality of curved-portion support members are provided so as to face the peripheral edge of the belt-shaped member curved so as to be convex outward. Supporting and transporting the belt-like member 101 via the inner ring 113 to form a cylindrical side wall, and again changing the transport direction while sandwiching the belt-like member 101 between the opening support outer roller 111 and the opening support inner roller 112 again. Thereby, it can be formed in a columnar shape. Further, as described above, in order to prevent the belt member 101 from being twisted or sagged during transportation, the belt member supporting outer roller 108 and the belt member supporting inner roller 109 are also provided on portions other than the curved portion of the belt member 101.
Thus, the belt-shaped member 101 is supported and conveyed while being sandwiched between them.

In FIG. 1, a slit-shaped opening 110 composed of a band-shaped member 101 maintains the shape of the opening by supporting the band-shaped member 101 with an opening supporting outer roller 111 and an opening supporting inner roller 112. The opening supporting inner roller 112 contacts only the peripheral portion of the belt-shaped member 101, and the belt-shaped member 10 is contacted from outside the film forming chamber by a separately provided driving mechanism (not shown).
Drive one. By providing a tension adjusting mechanism in the drive mechanism, it is possible to carry out the transfer without slack.

In FIG. 1, three gas introduction pipes, 106a, 106b, 106c
Is disposed inside a film forming chamber 104, and is disposed in a columnar film forming space formed by a dielectric tube 103 and a curved band-shaped member 101, as shown in FIG. Tubes 106a, 10
A large number of small holes 105 provided on 6b and 106c are arranged in a direction toward the belt-shaped member 101.

Although the belt-shaped member 101 is grounded, it is preferable that the strip-shaped member 101 is uniformly grounded over substantially the entire side wall portion of the columnar film forming chamber, and the opening supporting outer roller 111, the opening supporting inner roller 112, and the curved supporting inner ring are provided. It is desirable to be grounded via an electric brush (not shown) which contacts the side wall of the belt-shaped member 113 or the like.

A mechanism for introducing microwave power into the film forming chamber 104 shown in FIG. 1 will be described with reference to FIG.

In FIG. 3, a coaxial line is described as an example of the microwave antenna means, but an antenna means such as a Risitano coil may be used.

In FIG. 3, 301 is a rectangular waveguide, 302 is a coaxial blanker (movable terminal), 303 and 304 are electromagnetic shield members, 30
5 is a coaxial brazier fixing member, 306 is a circular cylinder yoke flange, 307 is a microwave permeable high dielectric member, 308 is a curved portion supporting inner ring, 309 is a roller or bearing, 310 is a central conductor cooling gas inlet, 311 Is a small hole, 312 is a stopper, and 313 is a waveguide coaxial converter.

As shown in FIG. 3, the center conductor 102 has a hollow structure, and one end of the center conductor 102 protrudes into the film forming chamber 104, exits the coaxial line through the waveguide coaxial converter 313, and ends at the other end. Is the central conductor cooling gas inlet 310. Center conductor 102
The electrical contact is well maintained by electromagnetic shielding members 303 and 304 made of a spring material and a center conductor fixing member (not shown). The center conductor fixing member may have the same structure as the coaxial plunger fixing member 305, for example, and may be arranged so that the mounting position is rotated by 90 ° around the axis of the center conductor. In FIG. 3, this fixing member is replaced by a simple bolt. By moving a portion of the central conductor 102 near the electromagnetic shield member 304, the insertion length of the central conductor 102 into the film forming chamber 104 can be adjusted from outside the coaxial line.

In FIG. 3, the coaxial plunger 302 has a structure that can be operated from the outside of the coaxial line as is apparent from the figure. An electromagnetic shield member 303 for improving electrical contact with a spring material is fixed to the coaxial plunger 302 by fastening or spot welding. At the center of the coaxial plunger 302, there is a hole through which the center conductor 102 can pass, and another electromagnetic shield member 303 made of a spring material is provided so that the coaxial plunger 302 can slide smoothly along the center conductor 102. It is provided in the contact part.

Further, a step portion is provided in the center conductor 102 in the middle, for example, a stopper 312 is provided, and the microwave permeable dielectric tube 103 and the end of the center conductor 102 come into contact with each other, and the dielectric tube 103 is damaged. It is practically more convenient to devise it. A similar stopper is provided at the other end of the coaxial plunger 302 so that the terminal surface of the coaxial plunger 302 does not protrude to the waveguide coaxial converter 313. If this portion protrudes, abnormal discharge is likely to occur in the electromagnetic shield member 303 that makes good contact between the coaxial probe 302 and the outer conductor, and in some cases, it burns out, causing a practical problem.

In FIG. 3, a waveguide coaxial converter 313 is formed by penetrating a coaxial line having a center conductor 102 into a rectangular waveguide 301.

In FIG. 3, the rectangular waveguide 301 is fastened to a 2.45 GHz microwave oscillator (not shown) manufactured by Evitz Shokai Co., Ltd.

In FIG. 3, a microwave permeable high dielectric constant member 30 is shown.
The shape of 7 is substantially a truncated cone, and a plurality of holes for discharging the cooling gas are provided on the conical surface. Therefore, the central conductor cooling gas flows from the central conductor cooling gas inlet 310 through the center of the central conductor 102 having a hollow structure, passes through the terminal opening of the central conductor 102, and along the inner surface of the microwave transmitting dielectric tube 103, The light is discharged from a plurality of small holes 311 provided on the side wall of the rectangular waveguide 301 through a discharge port provided on the conical surface of the microwave-permeable high dielectric member 307.

In FIG. 3, the belt-shaped member 101 is supported / transported only by a pair of curved portion supporting inner rings 308 to form a columnar space. Bend support inner ring 308
Is the roller (or bearing) placed around it
It is rotatably supported by 309, and both are grounded. The curved portion supporting inner ring is formed by a plurality of small rings as shown in FIG.
May be arranged on the peripheral portion of.

In FIG. 3, the center conductor 102 is isolated from the plasma generated in the film forming chamber 104 by the dielectric tube 103. The dielectric tube 103 has a hemispherical closed end at one end and a vacuum flange at the other end, and has a cylindrical portion therebetween, and has a structure capable of vacuum sealing with the vacuum flange. .

In FIG. 3, the circular chiyoke flange 306 is fastened so as to be in close contact with the vacuum flange of the dielectric tube 103, and the circular chiyoke flange 306 and the metal surface of the dielectric tube 103 are vacuum-sealed. Even if the electrical contact is not good, the structure has no microwave leakage.

The apparatus of the present invention is a microwave plasma CV as described above.
In addition to the main mechanism as the D apparatus, a load lock mechanism is provided as an auxiliary mechanism.

That is, the provision of the load lock mechanism shown in FIG. 5 not only reduced the defects generated in the deposited film, but also drastically improved the maintenance performance. The details of the load lock mechanism will be described below.

In FIG. 5, 501 is a replacement load lock chamber, 502 is a gate valve, 503 is a replacement door, 504 is a vacuum exhaust port, and are predetermined positions of a dielectric tube and a source gas introduction tube when a deposited film is formed. This represents the position when the user is pulled out of the predetermined position for these exchanges.

In FIG. 5, the center conductor 102, the dielectric window 103, and the three gas introduction pipes 106a, 106b, 106c are unitized so that they can be exchanged. The illustrated fixing members are prepared in advance at each position. An arm (not shown) for moving the unit from position to position is also provided in the replacement load lock chamber 501. A vacuum pump (not shown) is connected to the vacuum exhaust port 504 so that the inside of the replacement load lock chamber 501 can be evacuated. Further, the center conductor 102 and the gas introduction pipes 106a, 106
Both b and 106c are configured to be detachable near the gate valve 502. The load lock mechanism shown in FIG. 5 uses a gate valve 502 for the film forming chamber 104 shown in FIG.
Are arranged adjacent to each other.

In operating the microwave plasma CVD apparatus of the present invention described above, first, an initial discharge is easily caused to occur, and a film is formed in the film forming chamber 104 in accordance with a discharge state for forming a desired deposited film. A dielectric tube is provided so that the impedance of the coaxial line of the part that does not protrude and the coaxial line of the part that protrudes inside the film forming chamber 104 can be matched.
Two settings of adjusting and selecting the outer diameter of 103 in advance are made. Of course, even if this setting is performed, there may be a state where the operation of the present apparatus is not hindered, but the above setting is important in order to maximize the functions of the present apparatus.

First, in order to facilitate the initial discharge, which is the first setting, the pressure in the film forming chamber is increased, the microwave power to be supplied is increased, or a spark discharge is generated by a Tesler coil or the like. Various methods are known. In the apparatus of the present invention, the film forming chamber 104 constitutes the above-described semi-coaxial resonator, so that compared to the above-described conventional method for easily generating an initial discharge, a longer film forming pressure range can be used for a longer time. It has been found that a constant discharge can be sustained constantly over a period of time. Here, in order to form a semi-coaxial resonator, an HP8757A scalar network analyzer (manufactured by Huyett Packer) is used so that the semi-coaxial resonator is formed with the dielectric tube 103 attached to a predetermined position. The insertion length of the center conductor 102 into the film forming chamber 104 may be adjusted in advance while confirming the resonance state by using.

Next, the adjustment / selection of the outer diameter of the dielectric tube 103, which is the second setting, is performed by adjusting the coaxial line of the portion not protruding into the film forming chamber 104 and the coaxial line of the portion protruding inside the film forming chamber 104. What is necessary is just to carry out impedance matching with the line. That is, an equivalent coaxial line is formed inside the film forming chamber 104 where the discharge has occurred, according to the plasma density. The plasma density, that is, the complex permittivity of the plasma mainly changes depending on the gas mixing ratio, the gas pressure, the size of the microwave power dielectric tube to be introduced, and the like. Since these four variables are related to each other, the dielectric tube 10 in which the coaxial line rushed into the film forming chamber and the coaxial line not rushed into the above-described film formation chamber are in a matching state.
The optimal diameter of 3 is theoretically difficult to predict. Therefore, the matching state may be confirmed experimentally by selecting the outer diameter of the dielectric tube 103 and adjusting the insertion length of the center conductor 102 after the discharge into the film forming chamber 104.

In the case of the conditions shown in Table 8 of a film forming example 8 described later as a specific example, the following is obtained. That is, in a film forming chamber having an inner diameter of 40 mmφ, the center conductor is 6 mmφ, and the outer conductor is 20 mmφ.
Preferably, the outer diameter of the dielectric tube is about 1.8 mmφ and the insertion length of the center conductor is 452 mm. In the film forming chamber with an inner diameter of 105 mmφ, the center conductor is 15 mm
Preferably, the outer diameter of the dielectric tube is about 23 mmφ, and the insertion length of the center conductor is 455 mm.

When the microwave plasma CVD apparatus of the present invention described above is operated, the following is obtained.

1 is evacuated through a slit-shaped opening 110 and a vacuum exhaust port 107 by a vacuum pump (not shown). After the pressure inside the deposition chamber reaches 1 × 10 ⁻⁶ Torr,
A film forming source gas whose flow rate is independently controlled by a mass flow controller (not shown) is supplied to three gas introduction pipes 106.
The film is introduced into the film forming chamber 104 via each of a, 106b, and 106c.
After the pressure inside the film formation chamber reaches a predetermined pressure in this state,
The microwave power generated by a not-shown 2.45 GHz microwave oscillator (for example, manufactured by Evitz Shokai Co., Ltd.)
It is put into the film forming chamber through the rectangular waveguide 301, the waveguide coaxial converter 313, the center conductor 102, and the microwave transparent dielectric tube 103 shown in FIG. As is well known, it is preferable to match the impedance of microwaves in order to effectively utilize microwave power. In the device of the present invention,
A mechanism for adjusting the insertion length of the center conductor 102 and a coaxial plunger 302 shown in FIG. 3 are incorporated as a microwave impedance matching mechanism. Of these microwave impedance matching mechanisms, the former center conductor insertion length adjustment mechanism has a wider matching range, so first the reflected power is monitored as much as possible by a reflection power meter that monitors the reflected power inside the coaxial or waveguide. It is preferable that the impedance is adjusted by the insertion length adjusting mechanism so as to be small, and then finely adjusted by the coaxial plunger 302 to match the impedance. As a result, plasma is generated inside the film forming chamber 104. By the action of the plasma thus generated, a desired high-quality composition-controlled functional deposition film is formed on the belt-shaped member 101.

Next, the operation procedure of the load lock mechanism shown in FIG. 5, which is an auxiliary mechanism, will be described. First, the central conductor 102 and the gas introduction pipes 106a, 106b, 106c are removed near the gate valve 502, and the microwave transparent dielectric tube 103 and the gas introduction pipes 106a, 106b, 106c to be replaced are moved from the positions in the figure. Pull out to the position and close the gate valve 502. Next, the load lock chamber 501 is returned to the atmospheric pressure by using an inert gas such as N ₂ or Ar, the exchange door 503 is opened, and the dielectric tube 103 and the gas introduction tubes 106a, 106b, 106c are exchanged. After that, the replacement door 503
Is closed again, exhaust is performed from an exhaust port 504 through an exhaust pump (not shown), and when the pressures in the load lock chamber 501 and the film forming chamber become equal, the gate valve 502 is opened, and the dielectric tube 103 and gas introduction are performed. The pipes 106a, 106b, and 106c are returned to the positions, and the center conductor 102 and the gas introduction pipes 106a, 106
b and 106c are connected again near the gate valve 502. Then, the formation of the deposited film can be restarted.

As described above, the load lock mechanism plays an important role in increasing the operation rate of the device.
If a conductance adjusting mechanism is provided at the position of the exhaust port 107 in the figure, the operation rate of the apparatus is further increased, and the depreciation of the equipment is accelerated.

As shown in FIG. 6, the conductance adjusting mechanism uses a structure provided with a rotatable conductance adjusting plate 601 or a microwave reflecting plate 602 having a mesh structure, and rotates and fully opens at the time of initial evacuation. After reaching a predetermined pressure, the rotation position is determined so as to obtain a desired conductance, and the source gas may be flowed.

Further, as another conductance adjusting mechanism, the positions of the opposed rollers 111 and 112 shown in FIG. 6 may be shifted to the left and right, and the conductance may be controlled by effectively changing the area of the slit-shaped opening 110.

Apparatus Example 2 In this apparatus example, three film forming chambers shown in FIG. 1 are connected, and an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer are continuously formed on a continuously moving belt-like member. Microwave plasma CV suitable for producing pin-type photovoltaic devices by sequentially laminating and depositing
FIG. 2 shows a schematic cross-sectional view of a D apparatus.

In FIG. 2, 201 is a belt-like member, 202 is a belt-like member carry-in chamber, 203 to 205 are isolation containers, 206 is a gas isolation passage, 207 is a belt-like member carry-out chamber, 208 is a belt-like member feeding roller, and 209 is a belt-like member recovery ( Roller, 210, scavenging gas inlet, 211-213, film forming chamber, 214-216, microwave coaxial line introducing section, 217-225, exhaust port, 226, temperature control mechanism of belt-shaped member, 227, 228a, 228b, 228c, 229 are gas inlet pipes, 23
0 is a pressure gauge.

In FIG. 2, the load lock mechanism described in the first embodiment may be installed adjacent to the isolation containers 203 to 205 via a gate valve (not shown). In addition, the belt-like member loading room 20
A similar load lock mechanism may be installed in the second and belt-like member carry-out chambers 207.

In FIG. 2, a heating chamber is installed adjacent to the belt-like member carry-in chamber 202, a cooling chamber is installed in front of the belt-like member carry-out chamber 207, and heat flows from plasma in the film formation chamber. The cooling chamber and the heating chamber may be appropriately incorporated in the apparatus of the present invention.

In the apparatus shown in FIG. 2, it is possible to adjust the film thicknesses of the deposited films to be stacked by changing the inner diameters of the film forming chambers 211 to 213, even if the transport speed of the belt-shaped member 201 is constant. .

In FIG. 2, a gas isolation passage 206 is provided between all adjacent isolation containers, and the exhaust gas is introduced into the interior thereof through an exhaust gas inlet 210.

The gas isolation passage 217 is required to have a function of preventing the deposition film forming source gas used between adjacent isolation containers from diffusing. The basic concept can adopt the means disclosed in U.S. Pat. No. 4,438,723, but in the present invention, its capability must be further improved.
The reason is that a deposited film is desirably formed under a pressure of about 10 ⁻² to 10 ⁻³ Torr in at least one of the film forming chambers of the present invention, and the composition disclosed in the aforementioned US Pat. No. 4,438,723 is desirable. This is because the film forming pressure in the present invention is lower than the film pressure, and the source gas is easily diffused. Specifically it is necessary to withstand the pressure differential up to 10 ⁶ times,
As the exhaust pump, an oil diffusion pump, a turbo molecular pump, a mechanical booster pump, or the like having a large exhaust capacity, or a combination thereof is preferably used.

In order to reduce the conductance of the gas isolation passage 217 and enhance the isolation function, the cross-sectional shape of the gas isolation passage 217 is substantially the same as the cross-section of the strip-shaped member, and the isolation capability can be changed by changing the entire length of the gas isolation passage 217. . Further, it is preferable to use a scavenging gas in combination in order to enhance the sequestration capability. Examples of such a gas include a rare gas such as Ar, Ne, Kr, and Xe, which is easily exhausted by turbo molecules, and H ₂ gas.
A gas that is easily exhausted by an oil diffusion pump, such as a gas, is preferable. The optimum flow rate of the scavenging gas introduced into the gas isolation passage is substantially determined by the shape of the gas isolation passage and the mutual diffusion coefficient between the scavenging gas and the source gas for forming a deposited film. It is desirable to determine the optimal conditions by measuring the amount of gas diffusing with each other using a mass spectrometer or the like.

Prior to the operation of this apparatus, the strip-shaped member 201 which has been subjected to pre-treatment such as formation of a lower electrode is set on a feeding roller 208,
It winds around the winding roller 209 through a predetermined path of each of the isolation containers 203 to 205. Then, close the lid of each deposition chamber and
Vacuum is drawn down to about × 10 ^-6 Torr to complete preparation. The vacuum pump used at this time is a combination of a rotary pump, a mechanical booster pump, and an oil diffusion pump.

The operation of this device is as follows. Strip
201 is sent out from the belt-like member carrying-in chamber 202 at a constant transport speed and is heated to a predetermined temperature by the heating mechanism 226. Then, three layers of deposited films are formed via the isolation containers 203, 204, and 205, and the cooling mechanism 226 is formed. , And finally wound up by a take-up roller 209. After sufficient cooling, the roll of the belt-like member on which the deposited film is formed is taken out from the belt-like member discharge chamber 207.

 Regarding the winding mechanism in the apparatus of the present invention, it is desirable that the following functions are included: iv) protection of the film deposited during winding, and v) a roller shape that does not cause peeling of the film.

Specifically, when the belt 201 is wound by the winding roller 209, it is desirable to sandwich a polyimide nonwoven paper (so-called interleaf) together with the belt member 201 and wind it.

It is preferable that the material of the interleaving paper has heat resistance and flexibility of about 150 ° C., and in order to prevent peeling of the film, the outer diameter of the roller is preferably 100 mmφ or more, more preferably Desirably, it is about 300 mmφ.

In the apparatus of the present invention, if a mechanism capable of exchanging the belt-shaped member is provided in addition to the vacuum state in the film formation chamber, the film formation chamber will not be exposed to the atmosphere, and the moisture in the film formation chamber walls will not be exposed. Adsorption and the like can be eliminated, and a high-quality semiconductor device can be formed stably.

In the apparatus of the present invention, the inside of the film formation chamber can be cleaned by dry etching or the like as necessary while maintaining a vacuum state.

An example of a semiconductor device suitably manufactured by the method and apparatus of the present invention is a solar cell. FIGS. 9A to 9D schematically show typical examples of the layer structure.

In the example shown in FIG. 9A, the lower electrode 90
2, n-type semiconductor layer 903, i-type semiconductor layer 904, p-type semiconductor layer 9
05, a photovoltaic element 900 in which a transparent electrode 906 and a collecting electrode 907 are formed in this order. In this photovoltaic element, it is assumed that light is incident from the transparent electrode 906 side.

In the example shown in FIG. 9B, a transparent electrode 906, a p-type semiconductor layer 905, an i-type semiconductor layer 904, an n-type semiconductor layer 903, and a lower electrode 902 are deposited and formed in this order on a light-transmitting support 901. This is a photovoltaic element 900 '. In this photovoltaic element, it is assumed that light is incident from the transparent support 901 side.

The example shown in FIG. 9 (C) is a so-called pin-type photovoltaic element 911 or 912 using two types of semiconductor layers having different band gaps and / or layer thicknesses as i-layers, and is constituted by stacking two elements. This is a tandem photovoltaic element 913. Reference numeral 901 denotes a support, and the lower electrode 902, the n-type semiconductor layer 903, the i-type semiconductor layer 904, the p-type semiconductor layer 905, the n-type semiconductor layer 908, the i-type semiconductor layer 909, the p-type semiconductor layer 910, and the transparent electrode 906 And collecting electrode 9
07 are laminated in this order, and it is assumed that light is incident from the transparent electrode 906 side in this photovoltaic element.

The example shown in FIG. 9 (D) is constituted by stacking three pin junction type photovoltaic elements 920, 921 and 923 using three kinds of semiconductor layers having different band gaps and / or layer thicknesses as i-layers. Further, it is a so-called triple type photovoltaic element 924. 9
01 is a support, and the lower electrode 902, the n-type semiconductor layer 903, i
Semiconductor layer 904, p-type semiconductor layer 905, n-type semiconductor layer 914,
i-type semiconductor layer 915, p-type semiconductor layer 916, n-type semiconductor layer 91
7.The i-type semiconductor layer 918, the p-type semiconductor layer 919, the transparent electrode 906, and the current collecting electrode 907 are laminated in this order, and it is assumed that light is incident from the transparent electrode 906 side in this photovoltaic element. And

In any of the photovoltaic elements, the n-type semiconductor layer and the p-type semiconductor layer can be used in a different order of lamination according to the purpose.

Hereinafter, the configurations of these photovoltaic elements will be described.

Support The support 901 used in the present invention is preferably made of a material capable of forming a flexible curved shape, and may be either conductive or electrically insulating. Good. Furthermore, they may be translucent or non-translucent, but when light is incident from the support 901 side, they are translucent. It is necessary.

Specifically, the belt-like member used in the present invention can be mentioned, and by using the substrate, a solar cell to be manufactured can be reduced in weight, improved in strength, reduced in transportation space, and the like.

Electrodes In the present photovoltaic element, appropriate electrodes are selectively used depending on the configuration of the element. Examples of these electrodes include a lower electrode, an upper electrode (transparent electrode), and a collecting electrode. (However, the upper electrode referred to here indicates the electrode provided on the light incident side, and the lower electrode indicates the electrode provided opposite to the upper electrode with the semiconductor layer interposed therebetween.) The electrodes are described in detail below.

(I) Lower electrode The lower electrode 902 used in the present invention has a different surface on which light for generating photovoltaic light is irradiated depending on whether or not the material of the support 901 is translucent (for example, When the support 901 is made of a non-translucent material such as a metal, light for generating photovoltaic power is irradiated from the transparent electrode 906 side as shown in FIG. 9 (A)). Location is different.

Specifically, in the case of a layer configuration as shown in FIGS. 9A, 9C and 9D, it is provided between the support 901 and the n-type semiconductor layer 903. However, when the support 901 is conductive, the support can also serve as the lower electrode. However, if the sheet resistance is high even if the support 901 is conductive, the electrode is used as a low-resistance electrode for extracting current, or for the purpose of increasing the reflectivity on the support surface and making effective use of incident light. 902 may be installed.

In the case of FIG. 9 (B), a light-transmitting support 901 is used, and light enters from the support 901 side. For the purpose of current extraction and light reflection at the electrode, A lower electrode 902 is provided facing the support 901 with the semiconductor layer interposed therebetween.

When an electrically insulating material is used as the support 901, a lower electrode 902 is provided between the support 901 and the n-type semiconductor layer 903 as an electrode for extracting current.

As electrode materials, Ag, Au, Pt, Ni, Cr, Cu, Al, T
metals such as i, Zn, Mo, W or alloys thereof;
These metal thin films are formed by vacuum evaporation, electron beam evaporation, sputtering, or the like. Also, care must be taken that the formed metal thin film does not become a resistance component to the output of the photovoltaic element, and the sheet resistance is preferably 50Ω.
Or less, more preferably 10Ω or less.

Although not shown in the figure, a diffusion preventing layer such as conductive zinc oxide may be provided between the lower electrode 902 and the n-type semiconductor layer 903. The effect of the diffusion preventing layer is not only to prevent the metal element forming the electrode 902 from diffusing into the n-type semiconductor layer, but also to provide a slight resistance value so as to sandwich the semiconductor layer. The effect of preventing a short-circuit caused by a defect such as a pinhole between the lower electrode 902 and the transparent electrode 906 and generating multiple interference by a thin film to confine incident light in a photovoltaic element are given. be able to.

(Ii) Upper electrode (transparent electrode) The transparent electrode 906 used in the present invention has a light transmittance of 85% or more in order to efficiently absorb light from the sun or white fluorescent light into the semiconductor layer. Desirably,
Further, the sheet resistance is desirably 100Ω or less so that the output of the photovoltaic element does not become a resistance component. SnO ₂ as a material having such properties,
Metal oxides such as In ₂ O ₃ , ZnO, CdO, Cd ₂ SnO ₄ , ITO (In ₂ O ₃ + SnO ₂ ), and metal thin films formed of extremely thin and translucent metal such as Au, Al, Cu, etc. Is mentioned. The transparent electrode is laminated on the p-type semiconductor layer 805 in FIGS. 9 (A), 9 (C) and 9 (D), and is laminated on the substrate 901 in FIG. 9 (B). Therefore, it is necessary to select ones having good adhesion to each other. These fabrication methods include:
A resistance heating evaporation method, an electron beam heating evaporation method, a sputtering method, a spray method, and the like can be used, and are appropriately selected as desired.

(Iii) Current collecting electrode The current collecting electrode 907 used in the present invention is a transparent electrode 9
06 is provided on the transparent electrode 906 for the purpose of reducing the surface resistance value. Ag, Cr, Ni, Al, Ag, Au,
Examples include thin films of metals such as Ti, Pt, Cu, Mo, and W or alloys thereof. These thin films can be stacked and used. The shape and area of the semiconductor layer are appropriately designed so that the amount of light incident on the semiconductor layer is sufficiently ensured.

For example, it is desirable that the shape is uniformly spread over the light receiving surface of the photovoltaic element, and the area is preferably 15% or less, more preferably 10% or less, with respect to the light receiving area.

Further, as a sheet resistance value, preferably 50Ω or less,
More preferably, it is desirably 10Ω or less.

i-type semiconductor layer As the semiconductor material constituting the i-type semiconductor layer suitably used in the photovoltaic device manufactured by the present invention, A-Si: H, A-Si: F, A-Si: H: F , A-SiC: H, A-SiC: F, A-
SiC: H: F, A-SiGe: H, A-SiGe: F, A-SiGe: H: F, poly-Si:
In addition to so-called Group IV and Group IV alloy-based semiconductor materials such as H, poly-Si: F, and poly-Si: H: F, so-called compound semiconductor materials of Group II-VI and Group III-V and the like can be mentioned.

Among them, A-SiGe: H, A-SiGe: F, A-SiGe: H: F, A-SiC: H, A
When a so-called IV group alloy semiconductor such as -Si: F or A-SiC: H: F is used for the i-type semiconductor layer, the band gap from the light incident side (band gap: Eg ^opt ) is appropriately changed. It has been proposed that the open-circuit voltage (Voc) and the fill factor (FF) can be greatly improved. (20th IEEE PVSC,
1988, A NOVEL DESIGN FOR AMORPHOUS SILICON SOLARSE
LLS, S. Guha. J. Yang et al.) FIGS. 10 (a) to 10 (d) show specific examples of bandgap profiles. The mark → in the figure indicates the light incident side.

The bandgap profile shown in FIG. 10 (a) has a constant bandgap from the light incident side. No.
The bandgap profile shown in FIG. 10 (b) is of a type in which the bandgap on the light incident side is narrow and the bandgap gradually widens, and is effective in improving FF. No.
The handgap profile shown in FIG. 10 (c) is of a type in which the bandgap on the light incident side is wide and the bandgap gradually narrows, and is effective in improving Voc. The bandgap profile shown in FIG. 10 (d) is of a type in which the bandgap on the light incident side is wide, the bandgap narrows relatively steeply, and spreads again. By combining with FIG. 10 (c), both effects can be obtained simultaneously.

According to the method and apparatus of the present invention, for example, A-Si: H (Eg
^{Using opt} = 1.72 eV) and A-SiGe: H (Eg ^opt = 1.45 eV), an i-type semiconductor layer having a bandgap profile shown in FIG. 10D can be manufactured. Also, A-SiC: H
Using (Eg ^opt = 2.05 eV) and A-Si: H (Eg ^opt = 1.72 eV), an i-type semiconductor layer having a bandgap profile shown in FIG. 10C can be manufactured. I can do it.

Further, a semiconductor layer having a doping profile shown in FIGS. 11 (a) to 11 (d) can be manufactured by the method and the apparatus of the present invention. The mark → in the figure indicates the light incident side.

FIG. 11 (a) shows a profile of a non-doped i-type semiconductor layer. In contrast, FIG. 11 (b) shows a type in which the Fermi level on the light incident side is closer to the valence band and the Fermi level is gradually closer to the conduction band. Is effective in increasing FIG. 11 (c) shows a type in which the Fermi level gradually approaches the valence band from the light incident side, and differs from the case of FIG. 11 (b) when an n-type semiconductor layer is provided on the light incident side. There is a similar effect. FIG. 11 (d) shows a type in which the Fermi level changes to the conduction band due to the valence band almost continuously from the light incident side.

These illustrate the case where the band gap is constant from the light incident side shown in FIG. 10 (a), but FIG. 10 (b)
Also in the case of the bandgap profile shown in FIG. 10 (d), the fermi level can be controlled similarly.

By appropriately designing the bandgap profile and the fermi level profile, a photovoltaic element having high photoelectric conversion efficiency can be manufactured. In particular, these profiles are desirably applied to the i-type semiconductor layer of the tandem type or triple type photovoltaic element shown in FIGS. 9 (c) to 9 (d).

P-type semiconductor layer and n-type semiconductor layer P-type or n-type preferably used in the present photovoltaic device
The semiconductor material constituting the type semiconductor layer can be obtained by doping a valence electron controlling agent into the semiconductor material constituting the i-type semiconductor layer described above. Of course, it may be formed so as to have a doping profile shown in FIGS. 11 (a) to 11 (d).

(Production example)

Hereinafter, specific production examples using the microwave plasma CVD apparatus of the present invention will be described, but the present invention is not limited to these production examples.

Production Example 1 The continuous microwave plasma CVD apparatus (FIG. 2) shown in Apparatus Example 2 was used to continuously deposit an amorphous silicon germanium film.

First, a belt-like member loading chamber having a belt-like member delivery mechanism
In 202, a SUS430BA band member (width 46cm x length 100m x thickness 0.2mm), which has been sufficiently degreased and washed, is set with a wound band member feeding roller 208, and the band member 201 is set.
The gas isolation passage 206 and the opening support outer roller 111 in each of the isolation containers 203 to 205, the opening support inner roller 112,
And, through the curved portion support inner ring 113, through to the band-shaped member discharge chamber 207 provided with the band-shaped member collection roller 209,
The tension was adjusted to such an extent that there was no slack. Table 6 shows conditions such as the curved shape of the belt-shaped member and the arrangement of the gas introduction pipe.

Therefore, the belt-like member carrying-in chamber 201, the belt-like member carrying-out chamber 207, and the isolation containers 203 to 205 were roughly evacuated by a rotary pump (not shown), and then a mechanical booster pump (not shown) was started and evacuated to about 10 ^-3 Torr. After, further isolation container
By operating only the temperature control mechanism 226 arranged in the 204 and maintaining the substrate surface temperature at 270 ° C., a vacuum is reduced to 5 × 10 ⁻⁶ Torr or less by an oil diffusion pump (not shown) (Varian HS-32). I pulled.

At the time when the degassing was sufficiently performed, the raw material gas for forming the deposited film was introduced from each gas introduction pipe under the conditions shown in Table 7, and the opening of the throttle valve attached to the oil diffusion pump was adjusted. By adjusting the pressure, the pressure in the film forming chamber 212 was maintained at 22 mTorr. At this time, the pressure inside the isolation container 204 was 8 mTorr. When the pressure was stabilized, a microwave having an effective power of 0.8 kW was emitted from the center conductor 102 from a microwave power supply (not shown). Immediately, the introduced source gas was turned into plasma, and a plasma region was formed in the film formation chamber 212.

Therefore, the opening support outer roller 111, the opening support inner roller 112, and the curved support inner ring 113 (all the drive mechanisms are not shown) are activated, and the conveyance speed of the belt-shaped member is controlled to be 40 cm / min. did. Even when the transfer was started, the plasma was stable, and no particular change was observed.

It should be noted that H ₂ gas was flowed through the exhaust gas inlet 210 into the gas isolation passage 206 as exhaust gas at 50 sccm. After starting transport
The deposited film was formed continuously for 30 minutes. Since a long strip-shaped member is used, another deposited film is continuously formed after the completion of the present film formation example, and after all the depositions are completed, the strip-shaped member is cooled and taken out, and the main film is formed. The film thickness distribution of the deposited film on the belt-shaped member formed in the example was measured in the width direction and the longitudinal direction, and was found to be within 5%, and the deposition rate was 35 ° / sec on average.

A portion of the substrate on which the deposited film was formed was arbitrarily cut out at six locations, and the composition of the deposited film in the depth direction was analyzed using SIMS (ims-3f manufactured by CAMECA). A profile was obtained, and it was found that the bandgap profile shown in FIG. 10 (b) was formed. The total amount of hydrogen in the film was determined using a hydrogen-in-metal analyzer (EMGA-1100, manufactured by HORIBA, Ltd.) to be 18 ± 2 atomic%.

Production Example 2 Following the deposition film forming process performed in Production Example 1, the introduction of the used raw material gas was stopped, and the internal pressure of the isolation container 204 was evacuated to 5 × 10 ⁻⁶ Torr or less. Under the conditions, the source gas for forming the deposited film is introduced from each gas introduction pipe, the internal pressure is maintained at 23 mtorr, and the microwave power is 0.9 kW
A deposited film was continuously formed under the same conditions except that the above conditions were satisfied.

After the end of this production example and other production examples, the substrate was cooled and taken out, and the film thickness distribution of the deposited film formed in this production example was measured in the width direction and the longitudinal direction. The deposition rate averaged 48Å / sec.

A part of the substrate on which the deposited film was formed was arbitrarily cut out at six locations, and the composition of the deposited film in the depth direction was analyzed using SIMS (ims-3f manufactured by CAMECA). The depth profile shown in FIG. An isle was obtained, and it was found that the bandgap profile shown in FIG. 10 (d) was formed. The total amount of hydrogen in the film was determined using a hydrogen-in-metal analyzer (EMGA-1100, manufactured by HORIBA, Ltd.) and found to be 17 ± 2 atomic%.

Production Example 3 Following the deposition film forming process performed in Production Example 1, the introduction of the used raw material gas was stopped, and the internal pressure of the isolation container 204 was evacuated to 5 × 10 ⁻⁶ Torr or less. Under the conditions, a source gas for forming a deposited film is introduced from each gas introduction pipe, the internal pressure is maintained at 26 mTorr, and microwave power is 1.5 kW.
The deposited film was continuously formed under the same conditions except that the transfer speed was 35 cm / min.

After the end of this production example and other production examples, the substrate was cooled and taken out, and the film thickness distribution of the deposited film formed in this production example was measured in the width direction and the longitudinal direction. The deposition rate averaged 52Å / sec.

Six portions of the substrate on which the deposited film was formed were arbitrarily cut out, and the composition of the deposited film in the depth direction was analyzed using SIMS (ims-3f manufactured by CAMECA). The depth profile shown in FIG. 14 was obtained. An isle was obtained, and it was found that the bandgap profile shown in FIG. 10 (c) was formed. The total amount of hydrogen in the film was determined using a hydrogen-in-metal analyzer (EMGA-1100, manufactured by HORIBA, Ltd.) to be 14 ± 2 atomic%.

Production Example 4 After the internal pressure of the isolation container 204 was evacuated to 5 × 10 ⁻⁶ Torr or less in the same manner as in the deposited film formation process performed in Production Example 1, the deposited film was passed through each gas introduction pipe under the conditions shown in Table 10. A deposition film was formed under the same conditions except that a forming material gas was introduced, the internal pressure was maintained at 24 mTorr, and the microwave power was set to 1.2 kW.

After the end of this production example and other production examples, the substrate was cooled and taken out, and the film thickness distribution of the deposited film formed in this production example was measured in the width direction and the longitudinal direction. The deposition rate averaged 110 ° / sec.

Six portions of the substrate on which the deposited film was formed were arbitrarily cut out, and the composition of the deposited film in the depth direction was analyzed using SIMS (ims-3f manufactured by CAMECA). The depth profile shown in FIG. 15 was obtained. An isle was obtained, and it was found that a doping profile almost as shown in FIG. 11 (b) was formed. The total amount of hydrogen in the film was determined using a hydrogen-in-metal analyzer (EMGA-1100, manufactured by HORIBA, Ltd.) to be 18 ± 2 atomic%.

Production Example 5 In this production example, a pin-type photovoltaic element having a layer configuration shown in the schematic sectional view of FIG. 9A was produced using the apparatus shown in FIG.

The photovoltaic element comprises a substrate 901, a lower electrode 902, an n-type semiconductor layer 903, an i-type semiconductor layer 904 having a band gap profile shown in FIG. This is a photovoltaic element 900 in which an electrode 906 and a collecting electrode 907 are formed in this order. In this photovoltaic element, it is assumed that light is incident from the transparent electrode 906 side.

First, a SUS430BA strip-shaped substrate similar to that used in Production Example 1 was set in a continuous sputter device, and a 1000 mm Ag thin film was continuously formed using an Ag (99.99%) electrode as a target, and ZnO (99.999%) continuously. 1.2 using electrodes as targets
A μm ZnO thin film was sputter-deposited to form a lower electrode 902.

Subsequently, the strip-shaped substrate on which the lower electrode 902 was formed was set in the continuous deposition film forming apparatus shown in FIG. 2 in the same manner as in Production Example 1. Table 11 shows conditions such as the curved shape of the substrate in the isolation container 204 at this time. Under the conditions shown in Table 12, source gases for forming a deposited film were introduced from the respective gas introduction pipes.

In the isolation containers 203 and 205, an n-type A-Si: H: F film and a p ⁺ -type μc-Si: H: F film were formed under the deposition film forming conditions shown in Table 13.

First, microwave plasma is generated in each deposition chamber, and when discharge and the like are stabilized, the belt-shaped member 201 is transported from the left to the right in the drawing at a transport speed of 41 cm / min, and continuously n, i, p-type. A semiconductor layer was formed by lamination.

After laminating and forming a semiconductor layer over the entire length of the belt-shaped member 201, take out after cooling, and further, with a continuous modularization device
A 35 cm × 70 cm solar cell module was produced continuously.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ² ) When the characteristics were evaluated under light irradiation, a photoelectric conversion efficiency of 7.5% or more was obtained, and the variation in characteristics between modules was within 5%.

In addition, the rate of change of the photoelectric conversion efficiency from the initial value after 500 hours of continuous irradiation with AM1.5 (100 mW / cm ² ) light was measured.
It fell within 9.5%.

By connecting these modules, a 5kW power supply system could be made.

Production Example 6 In this production example, in the pin-type photovoltaic device produced in Production Example 5, the bandgears shown in FIG. 10 (c) were used instead of the A-SiGe: H: F film as the i-type semiconductor layer. An example using an A-SiC: H: F film having a profile is shown.

For the A-SiC: H: F film, the raw material gas for forming the deposited film was introduced from each gas introduction tube under the conditions shown in Table 14, the surface temperature of the strip-shaped member was maintained at 250 ° C., and the internal pressure was maintained at 36 mTorr. The wave power was set to 1.6 kW. And the transfer speed is 45cm / min
Other semiconductor layers were formed and modularized by the same operation and method as in Production Example 5 except for the above, and a solar cell module was fabricated.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ² ) When the characteristics were evaluated under light irradiation, a photoelectric conversion efficiency of 6.8% or more was obtained, and the variation in characteristics between modules was within 5%.

In addition, the rate of change of the photoelectric conversion efficiency from the initial value after 500 hours of continuous irradiation with AM1.5 (100 mW / cm ² ) light was measured.
It fell within 9.5%.

By connecting these modules, a 5kW power supply system could be made.

Production Example 7 In this production example, in the pin-type photovoltaic element produced in Production Example 5, a fermilevel shown in FIG. 11B was used instead of the A-SiGe: H: F film as the i-type semiconductor layer. An example using an A-Si: H: F film having a profile will be described.

For the A-Si: H: F film, the raw material gas for forming the deposited film was introduced from each gas introduction tube under the conditions shown in Table 15, the surface temperature of the belt-shaped member was maintained at 270 ° C., and the internal pressure was maintained at 45 mTorr. Wave power
It was formed as 2.5kW. Then, another semiconductor layer was formed and formed into a module by the same operation and method as in Production Example 5 except that the transfer speed was set to 50 cm / min, thereby producing a solar cell module.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ²⁾ was subjected to characteristic evaluation under optical irradiation, more than 8.5% in photoelectric conversion efficiency being obtained, further variations in characteristics among modules is accommodated within 5%.

In addition, the rate of change of the photoelectric conversion efficiency from the initial value after 500 hours of continuous irradiation with AM1.5 (100 mW / cm ² ) light was measured.
It fell within 9.5%.

By connecting these modules, a 5kW power supply system could be made.

Production Example 8 In this production example, a photovoltaic element having a layer configuration shown in FIG. 9C was produced. In manufacturing, an apparatus (not shown) in which the isolation containers 203 ', 204', and 205 'having the same configuration as the isolation containers 203, 204, and 205 in the apparatus shown in Fig. 2 are further connected in this order via a gas gate. Was used.

The band-shaped member was made of the same material and processed as used in Production Example 1, and the lower cell was produced in Production Example 5.
The upper cell has the same layer configuration as that produced in Production Example 7, and the production condition of each semiconductor layer is such that the surface temperature of the belt-like member is 270 ° C., 260 ° C., 260 ° C., 250 ° C. 250
The temperature was the same as in each of the production examples except that the temperature was 240 ° C.
The module-forming step was performed in the same operation and method as in Production Example 5 to produce a solar cell module.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ²⁾ was subjected to characteristic evaluation under optical irradiation, more than 10.4% in photoelectric conversion efficiency being obtained, further variations in characteristics among modules is accommodated within 5%.

Further, the rate of change of the photoelectric conversion efficiency with respect to the initial value after continuous irradiation of AM1.5 (100 mW / cm ² ) light for 500 hours was within 9%.

By connecting these modules, a 5kW power supply system could be made.

Production Example 9 In this production example, a photovoltaic element having a layer configuration shown in FIG. 9C was produced. At the time of fabrication, an apparatus (not shown) in which an isolation container having the same configuration as the isolation containers 203, 204, and 205 in the apparatus shown in FIG. ) Was used.

The band-shaped member was made of the same material and processed as used in Production Example 1, and the lower cell was produced in Production Example 7.
The upper cell has the same layer configuration as that produced in Production Example 6, and the production condition of each semiconductor layer is such that the surface temperature of the belt-like member is 270 ° C., 270 ° C., 260 ° C., 250 ° C. 240
The temperature was the same as in each of the production examples except that the temperature was 240 ° C.
The module-forming step was performed in the same operation and method as in Production Example 5 to produce a solar cell module.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ²⁾ was subjected to characteristic evaluation under optical irradiation, more than 10.3% in photoelectric conversion efficiency being obtained, further variations in characteristics among modules is accommodated within 5%.

Further, the rate of change of the photoelectric conversion efficiency with respect to the initial value after continuous irradiation of AM1.5 (100 mW / cm ² ) light for 500 hours was within 9%.

By connecting these modules, a 5kW power supply system could be made.

Production Example 10 In this production example, a photovoltaic element having a layer configuration shown in FIG. 9D was produced. At the time of fabrication, isolation containers 203 ', 204', 205 ', 203 ", 204", and 205 "having the same configuration as the isolation containers 203, 204, and 205 in the apparatus shown in FIG. A connected device (not shown) was used.

The band-shaped member was made of the same material and treated as used in Production Example 1, and the lower cell was prepared in Production Example 5.
The intermediate cell has the same layer configuration as that of the production example 7 and the upper cell has the same layer constitution as that of the production example 6, and the conditions for producing the deposited film of each semiconductor layer are shown in Tables 16 to 17. The module-forming step was performed in the same operation and method as in Production Example 5 to produce a solar cell module.

For the fabricated solar cell module, AM1.5 (100mW
/ cm ²⁾ was subjected to characteristic evaluation under optical irradiation, more than 10.6% in photoelectric conversion efficiency being obtained, further variations in characteristics among modules is accommodated within 5%.

In addition, the rate of change of the photoelectric conversion efficiency from the initial value after 500 hours of continuous irradiation with AM1.5 (100 mW / cm ² ) light was measured.
Within 8.5%.

By connecting these modules, a 5kW power supply system could be made.

[Summary of effects of the invention]

According to the method of the present invention, the belt-shaped member constituting the side wall of the film forming space is continuously moved, and two or more kinds of deposited film forming source gases having different compositions are respectively introduced into the film forming space by a plurality of gases. Introduced separately through the gas supply means, the microwave antenna means is rushed into the film forming space so as to be parallel to the width direction of the belt-shaped member constituting the side wall of the film forming space, and from the microwave antenna means By radiating microwave energy in all directions perpendicular to the direction in which the microwave travels, and confining the microwave plasma in the film forming space, a large-area composition-controlled functional deposition film is continuously formed. It can be formed with good reproducibility.

Further, a functional deposition film having an arbitrary band cap file and a doping profile can be efficiently and continuously formed on a continuously moving belt-shaped member by the method and apparatus of the present invention.

By confining the microwave plasma in the film forming space by the method and apparatus of the present invention, the stability and reproducibility of the microwave plasma are improved, and the utilization efficiency of the source gas for forming the deposited film is dramatically increased. Can be. Further, by continuously transporting the band-shaped member,
By variously changing the shape, length, and transfer speed of the curve, a deposited film having an arbitrary composition distribution and film thickness can be continuously deposited with good uniformity over a large area.

ADVANTAGE OF THE INVENTION According to the method and apparatus of this invention, the functional deposition film whose composition is controlled with good uniformity can be formed continuously on the surface of a comparatively wide and long strip-shaped member. Therefore, it can be suitably used particularly as a mass-producing machine for high-efficiency large-area solar cells.

In addition, since a deposited film can be formed continuously without stopping discharge, good interface characteristics can be obtained when a stacked device or the like is manufactured.

In addition, it is possible to form a deposited film under a low pressure, which suppresses the generation of polysilane powder and suppresses the polymerization of active species, thereby reducing defects, improving film characteristics, and stabilizing film characteristics. Can be improved.

Therefore, it is possible to improve the operation rate and the yield, and mass-produce inexpensive and highly efficient solar cells.

Further, the solar cell manufactured by the method and the apparatus of the present invention has high photoelectric conversion efficiency and has less characteristic deterioration over a long period of time.

[Brief description of the drawings]

1 is a perspective explanatory view of a film forming chamber and its peripheral mechanism in the apparatus of the present invention, and FIG. 2 is a schematic side sectional view of a microwave plasma CVD apparatus suitable for producing a pin-type photovoltaic element. FIG. 3 is a detailed explanatory view of the microwave coaxial line, FIG.
FIG. 5 is a cross-sectional view taken along the line AA ′ of FIG. 3, FIG. 5 is an explanatory view of an exchange mechanism of a dielectric tube and a raw material gas introducing pipe, FIG. , FIG. 8 is data of a film formation result evaluation example, and FIGS. 9A to 9D are pin type photovoltaic elements (single, tandem,
3 is a schematic sectional view of (Triple). FIGS. 10 (a) to (d) are views for explaining a band cap profile of a deposited film formed by the present invention. FIGS. 11 (a) to 11 (d) are diagrams for explaining the doping profile of the deposited film formed by the present invention.
FIG. 12 to FIG. 15 are diagrams showing the depros profiles of the component elements of the deposited films formed in Production Examples 1 to 4 of the present invention. FIG. 16 and FIG. 17 are schematic diagrams of a conventional microwave antenna system. Each of FIGS. 1 to 17 includes a band member 101, a central conductor 102, a dielectric tube 103a, 106b, 106c, a gas introduction tube 110, a slit-shaped opening 113 ... Bending portion support inner ring 201, Band member 203-205 Isolation container 206 Gas isolation passage 210 Exhaust gas inlet 211-213 Film formation chamber 214
... 216 ... microwave coaxial line introduction part, 217-225 ... exhaust port, 226 ... temperature control mechanism, 227, 228a, 228b, 228c,
229 gas inlet pipe 230 pressure gauge 301 rectangular waveguide 302 coaxial plunger 901 support body 902
Lower electrode, 903, 908, 914, 917 ... n-type semiconductor layer, 90
4, 909, 915, 918, i-type semiconductor layer, 900, 900 ', 911, 9
12, 920, 921, 923 ... pin junction type photovoltaic element, 905, 9
10, 916, 919: p-type semiconductor layer, 906: upper electrode, 907
…… collecting electrode, 913 …… Tandem photovoltaic element, 924…
… Triple type photovoltaic element, 1601 …… Reaction vessel, 1602…
… Rod antenna, 1609 …… Microwave transmitting member, 17
01: reaction vessel, 1704: coaxial line, 1705: gap provided in outer conductor, 1706: cylindrical body.

Claims (18)

(57) [Claims] 1. A belt-like member is moved in a longitudinal direction, and a film forming space having a side wall on the band-like member is formed in the middle of the band-like member, and at least two or more kinds of depositions having different compositions are formed in the formed film-forming space. Each of the film forming source gases is separately introduced through a plurality of gas supply units, and simultaneously, the microwaves are transmitted through a microwave antenna unit surrounded by a microwave transmitting member disposed in the film forming space. Microwaves are uniformly radiated in all directions perpendicular to the traveling direction, and microwave power is applied to the film formation space to generate microwave plasma in the film formation space. A deposited film is formed on the strip-shaped member constituting the side wall to be formed by a microwave plasma CVD method. 2. In the middle of the band-shaped member, the bending start end forming unit and the bending end end forming unit are used to interpose the band-shaped member between the bending start end forming unit and the bending end end forming unit. The method according to claim 1, wherein the band-shaped member is curved while leaving a gap in a longitudinal direction to form a side wall of the film forming space. 3. The band-shaped member has a linear expansion coefficient larger than a linear expansion coefficient of the deposited film to be deposited, and the band-shaped member is heated in the film formation space and reaches room temperature outside the film formation space. 2. The method according to claim 1, further comprising, when being cooled, the belt-shaped member is developed and cooled on a plane, or is wound and cooled so that the surface on which the deposited film is formed is on the outside. . 4. The microwave antenna means is rushed into the film-forming space from one of two opposing side surfaces of a film-forming space formed with the band-shaped member as a side wall, thereby transmitting the microwave energy. The method for forming a deposited film according to claim 1, wherein the deposited film is radiated or transmitted into a film forming space. 5. The method according to claim 1, wherein said microwave transmitting member separates said microwave antenna means from plasma generated in said film forming space. 6. The gas supply means is disposed in parallel with the width direction of the band-shaped member constituting each of the side walls, and the source gas for forming a deposited film is discharged in one direction toward the adjacent band-shaped member. The method for forming a deposited film according to claim 1. 7. The method for forming a deposited film according to claim 1, wherein a surface of the band-shaped member exposed to the microwave plasma is subjected to at least a conductive treatment. 8. A deposition film forming apparatus for moving a belt-shaped member in a longitudinal direction and forming a deposited film on the belt-shaped member in the middle thereof, wherein the deposition film-forming apparatus is provided between the belt-shaped members in a longitudinal direction for supporting the belt-shaped member. A film forming space is provided in the middle of moving from the feeding mechanism to the winding mechanism in the longitudinal direction by a set of rollers arranged in parallel with each other with a predetermined space, and the band-shaped member functions as a wall. Film-forming space forming means for supporting the strip-shaped member for forming; and microwave transmission arranged in the film-forming space for uniformly radiating microwaves in all directions perpendicular to the direction of microwave propagation. Microwave antenna means surrounded by a member; exhaust means for exhausting the inside of the film forming space; at least two or more gas supplies for introducing a source gas for forming a deposited film into the film forming space And a temperature control unit for heating or cooling the belt-shaped member. 9. The deposited film forming apparatus according to claim 8, wherein said microwave antenna means is a coaxial line, and said microwave transmitting member has a central conductor and a microwave transmitting member provided therearound. 10. The roller comprises a curved portion forming means for curving the band-shaped member, and the curved portion forming means comprises at least one set of a curved start end forming means and a curved end end forming means. 9. The deposition film forming apparatus according to claim 8, wherein the film forming space is provided between the bending start end forming unit and the bending end end forming unit. 11. The deposited film forming apparatus according to claim 8, wherein said film forming space forming means comprises a pair of said rollers and a supporting and conveying ring disposed between said rollers. 12. The microwave antenna according to claim 8, wherein said microwave antenna means protrudes from one of side surfaces of said film forming space into said film forming chamber so as to be substantially parallel to a width direction of said band-shaped member. The deposited film forming apparatus as described in the above. 13. The deposition film forming apparatus according to claim 8, wherein said microwave transmitting member is rotationally symmetric. 14. The deposition film forming apparatus according to claim 13, wherein said microwave transmitting member has a cylindrical shape, a truncated cone shape, or a conical shape. 15. An apparatus according to claim 9, wherein at least two tuning means are provided on said coaxial line. 16. The deposited film forming apparatus according to claim 15, wherein one of said two tuning means is an insertion length adjusting mechanism of a center conductor of a microwave antenna means protruding into said film forming space. 17. The apparatus according to claim 8, wherein said gas supply means is disposed in parallel with a width direction of the belt-like member constituting said side wall.
3. The deposited film forming apparatus according to item 1. 18. The deposition film forming apparatus according to claim 17, wherein said gas supply means is provided with a gas discharge hole directed to a belt-like member constituting said side wall adjacent to said gas supply means.