JPH07297423A - Formation of photovoltaic element - Google Patents

Abstract

PURPOSE:To provide a photovoltaic element forming method by which a photovoltaic element having good characteristics can be manufactured by using such a hydrogen plasma treatment method that the taking in of impurities adsorbed to or contained in the internal wall surface of a chamber can be substantially prevented and stable discharge can be obtained. CONSTITUTION:In a photovoltaic element forming method in which one or more pin structures formed by successively piling up a non-single crystal n-type layer 103 containing silicon atoms, non-single crystal i-type n/i buffer layer 151, non-single crystal i-type layer 104, non-single crystal i-type p/i buffer layer 161, and non-single crystal p-type layer or n-type layer 105 upon another are piled up on a substrate, the vicinity of the interface between the layers 151 and 103 is subjected to plasma treatment performed by using a hydrogen gas mixed with a gas containing silicon atoms in such a degree that the atoms do not accumulate substantially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention laminates a non-single-crystal n-type layer (or p-type layer) containing silicon atoms, a non-single-crystal i-type layer and a non-single-crystal p-type layer (or n-type layer). Formed by pi
The present invention relates to a method for forming a photovoltaic element such as a Taiyo battery or a sensor, which is formed by stacking at least one or more n structures.

[0002]

2. Description of the Related Art Conventionally, defects existing in semiconductors are closely related to the generation and recombination of electric charges and deteriorate the characteristics of the device.

As a method of compensating for such a defect level,
Hydrogen plasma treatment has been proposed. For example, USP4
113514 (JI Pankove et al., RCA S
ep. 12, 1978), hydrogen plasma treatment of completed semiconductor devices is described. See also “EFFE
CT OF PLASMA TREATMENT OF THE TCO ON a-Si SOLARCEL
L PERFORMANCE ", F.Demichelis et.al., Mat.Res.Soc.S
ymp.Proc.Vol.258, p9O5,1992 shows a method of forming a pin structure solar cell on a transparent electrode deposited on a substrate by hydrogen plasma treatment. Furthermore, "HYDROGEN
-PLASMA REACTION FLUSHING F0R a-Si: H PIN SOLAR C
ELL FABRlCATION ", YSTsuo et.al., Mat.Res.Soc.Symp.
Proc. Vol. 149, p471, 1989 shows that in a solar cell having a pin structure, the surface of the p layer is treated with hydrogen plasma before the deposition of the i layer. In the conventional hydrogen plasma treatment as described above, only hydrogen gas is introduced into the chamber and RF
Hydrogen gas was activated by power to perform hydrogen plasma treatment.

However, the hydrogen plasma not only spreads so as to act on the substrate to be processed, the unfinished device and the completed device, but also spreads throughout the chamber. Since hydrogen plasma is very active, impurities (such as oxygen, which are adsorbed or contained in the wall surface and become defect levels when incorporated into the semiconductor layer from the wall surface of the chamber).
There is a problem that nitrogen, carbon, iron, chromium, nickel, aluminum, etc.) are taken out.

Further, hydrogen gas is more difficult to generate an electric discharge than other gases, and it is difficult to perform stable hydrogen plasma treatment on plasma using only hydrogen gas because it is more difficult to maintain plasma than other gases. There is a problem.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems. That is, an object of the present invention is to provide a hydrogen plasma treatment method that substantially prevents the inclusion of impurities adsorbed on or contained in the chamber wall surface, and to provide a more stable hydrogen plasma treatment method. is there.

Another object of the present invention is to provide a method for forming a photovoltaic element in which the semiconductor layer is not substantially peeled off even when the photovoltaic element is placed in high temperature and high humidity.

A further object of the present invention is to provide pi on a flexible substrate.
Another object of the present invention is to provide a method for forming a photovoltaic element in which the pin semiconductor layer is less likely to peel off even if the substrate is bent when the n structure is formed.

Further, it is an object of the present invention to provide a method for forming a photovoltaic element in which the defect level is less likely to increase near the interface between the n-type layer and the i-type semiconductor layer by irradiation with light for a long time. .

In addition to the above, an object of the present invention is to suppress the deterioration of the characteristics of the photovoltaic element such as the peeling of the substrate and the semiconductor layer and the increase of the series resistance when the light irradiation is performed under high temperature and high humidity. It is to provide a method for forming a power device.

An object of the present invention is to provide a photovoltaic element having improved initial efficiency by preventing diffusion of impurities from the n-type layer to the i-type layer.

Another object of the present invention is to provide a photovoltaic element which is less likely to deteriorate in characteristics when used at a high temperature.

[0013]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that the above object can be achieved by a method of forming a substrate and a semiconductor layer or between semiconductor layers.

That is, according to the present invention, a non-single-crystal n-type layer (or p-type layer) containing silicon atoms and a non-single-crystal i-type n / i buffer layer (or p / i buffer layer) are provided on a substrate. A non-single-crystal i-type layer, a non-single-crystal i-type p / i buffer layer (or n / i buffer layer), and a non-single-crystal p-type layer (or n-type layer) stacked at least In the method for forming a photovoltaic device having one or more laminated layers, plasma treatment is performed in the vicinity of an interface where the n / i buffer layer and the n-type layer are in contact with hydrogen gas containing a silicon atom-containing gas that does not substantially deposit. It is characterized by doing.

Further, according to the present invention, the vicinity of the interface between the substrate and the n-type layer (or the vicinity of the interface between the substrate and the p-type layer).
Is subjected to plasma treatment with hydrogen gas containing a silicon atom-containing gas to the extent that substantially no deposition occurs.

Further, according to the present invention, the silicon atom-containing gas is SiH ₄ , Si ₂ H ₆ , SiF ₄ , SiFH ₃ or SiF _2.
H ₂ , SiF ₃ H and SiC are ₂ H ₂ , SiCl ₃ H and SiC
It is characterized by containing at least one of l ₄ .

Furthermore, the present invention is characterized in that the content of the silicon atom-containing gas with respect to the hydrogen gas is 0.1% or less.

[0018]

When the hydrogen-containing gas is added to the extent that the silicon-containing gas does not substantially contribute to the deposition and the hydrogen plasma treatment is performed and then the semiconductor layer is deposited to form the photovoltaic element, the above object can be achieved. it can. Although the detailed mechanism thereof is not clear at present, the present inventors consider as follows.

That is, when hydrogen gas is added with a silicon atom-containing gas to an extent that does not substantially contribute to deposition and hydrogen plasma treatment is performed, the activated silicon atom-containing gas is adsorbed on the inner wall of the chamber. It acts on oxygen and water to generate stable silicon oxide and the like, which is more stable than that adsorbed on the inner wall of the chamber in the form of oxygen or water. As a result, when the silicon atom-containing gas is contained to the extent that it does not substantially contribute to the deposition and the plasma treatment is performed, it is possible to suppress the incorporation of impurities such as oxygen and water adsorbed on the chamber wall surface into the semiconductor to a very low level. It is thought that things can be done.

In addition, when hydrogen plasma treatment is performed with hydrogen gas containing a small amount of silicon atom-containing gas, hydrogen atoms on the chamber wall surface are suppressed from deeply diffusing into the chamber wall surface, and the chamber wall surface It is considered that it is possible to suppress as much as possible a reaction that takes out impurities that enter the semiconductor layer from the inside and form a defect level.

Further, hydrogen gas has a high ionization energy, and it is difficult to stably maintain plasma discharge for a long time. However, as in the present invention, a small amount of a silicon atom-containing gas that easily maintains plasma discharge is added to hydrogen gas. Depending on the matter
We believe that it will be easier to maintain the plasma discharge of hydrogen gas. By applying such a very stable hydrogen plasma discharge to the substrate or the element, the uniformity and reproducibility of the hydrogen plasma treatment are greatly improved. By improving the uniformity and reproducibility of such hydrogen plasma treatment, it is possible to prevent local peeling of the semiconductor layer and increase in series resistance under high temperature and high humidity and light irradiation for a hydrogen plasma treated substrate or element. It is possible.

In the hydrogen plasma treatment of the present invention, the surface of the substrate has a texture structure, and where the texture structure is locally sharply developed, the direction in which the silicon atom-containing gas is blunted is contained in the hydrogen plasma treatment. It works.
As a result, the abnormal growth of the semiconductor layer does not substantially occur even if the semiconductor layer is deposited on the textured substrate subjected to the hydrogen plasma treatment of the present invention. Therefore, when a photovoltaic element having a pin structure is formed, there is little unevenness in the characteristics of the photovoltaic element, and the adhesion between the substrate and the semiconductor layer is excellent,
In addition, a photovoltaic element having excellent durability under high temperature and high humidity can be obtained.

Further, when the hydrogen plasma treatment of the present invention is performed at the interface between the n-type layer and the n / i buffer layer, the diffusion of impurities from the n-type layer to the i-type layer can be prevented. Although the detailed mechanism is unknown, the present inventors consider as follows. When the surface of the n-type layer or the n / i buffer layer is subjected to the hydrogen plasma treatment containing a small amount of the silicon atom-containing gas of the present invention, defects or structural distortion on the surface of the n-type layer or the n / i buffer layer may occur. It is believed that this can be reduced by diffusion of active hydrogen plasma into the layer and diffusion of a small amount of silicon atoms contained in vacancies.

[0024]

Embodiments Embodiments of the present invention will be described in detail below.

First, a method and apparatus for forming a photovoltaic element according to the present invention will be described in detail with reference to the drawings.

(Hydrogen Plasma Treatment Condition) FIGS. 1 to 3 show an example of a photovoltaic element of the present invention which has been subjected to hydrogen plasma treatment with hydrogen gas containing a minute amount of silicon atom-containing gas.

FIG. 1 is a schematic explanatory view of a photovoltaic element having one pin structure. When the photovoltaic device emits light from the side opposite to the substrate, the substrate 190 (support 10
0, the reflective layer 101, the reflection increasing layer 102), the first n-type layer (or p-type layer) 103, the first n / i buffer layer (or p / i buffer layer) 151, the first i-type layer 1
04, first p / i buffer layer (or n / i buffer layer) 161, first p-type layer (or n-type layer) 10
5, a transparent electrode 112, and a collector electrode 113. When light is irradiated from the substrate side, 100 is a transparent support, 101 is a transparent conductive layer, 102 is an antireflection layer, and 112 is a conductive layer also serving as a reflective layer.

FIG. 2 is a schematic explanatory view of a photovoltaic device having two pin structures. The photovoltaic element is a substrate 290.
(Support 200, reflection layer 201, reflection enhancement layer 202),
First n-type layer (or p-type layer) 203, first n / i buffer layer (or p / i buffer layer) 251, first
I-type layer 204, first p / i buffer layer (or n
/ I buffer layer) 261, first p-type layer (or n-type layer) 205, second n-type layer (or p-type layer) 206, second n / i buffer layer (or p / i buffer layer) )
252, second i-type layer 207, second p / i buffer layer (or n / i buffer layer) 262, second p-type layer (or n-type layer) 208, transparent electrode 212, current collecting electrode 2
It is composed of 13. When light is emitted from the substrate side, 200 is a transparent support, 201 is a transparent conductive layer, 202 is an antireflection layer, and 212 is a conductive layer that also serves as a reflective layer.

FIG. 3 is a schematic explanatory view of a photovoltaic element having three pin structures. The photovoltaic element is a substrate 390.
(Support 300, reflection layer 301, reflection enhancement layer 302),
First n-type layer (or p-type layer) 303, first n / i buffer layer (or p / i buffer layer) 351, first
I-type layer 304, the first p / i buffer layer (or n
/ I buffer layer) 361, first p-type layer (or n-type layer) 305, second n-type layer (or p-type layer) 306, second n / i buffer layer (or p / i buffer layer) )
352, the second i-type layer 307, the second p / i buffer layer (or n / i buffer layer) 362, the second p-type layer (or n-type layer) 308, the third n-type layer (or p-type layer) 309, third n / i buffer layer (or p / i)
Buffer layer) 353, third i-type layer 310, third p
/ I buffer layer (or n / i buffer layer) 36
3, third p-type layer (or n-type layer) 311, transparent electrode 3
12 and a collector electrode 313. When light is irradiated from the substrate side, 300 is a transparent support, 301 is a transparent conductive layer, 302 is an antireflection layer, and 312.
Is composed of a conductive layer that also serves as a reflective layer.

The plasma treatment with the hydrogen gas containing the silicon atom-containing gas of such a level that substantially does not deposit is effective after the first n-type layer deposition. Further, the plasma treatment with the hydrogen gas containing the silicon atom-containing gas to the extent that the deposition is not substantially performed according to the present invention is more effective when performed on the substrate before the first n-type layer (or p-type layer) deposition. Target. The hydrogen flow rate suitable for achieving the object of the present invention is appropriately optimized depending on the size of the processing chamber, but a suitable flow rate is 1 to 2000 sccm. When the hydrogen flow rate is less than 1 sccm, the electric power for maintaining the plasma discharge becomes large, the damage to the base slope becomes severe, and the impurities are easily taken in from the chamber wall surface. Hydrogen flow rate is 2000 sccm
If the number is higher, the residence time of the silicon-based active species and hydrogen active species in the plasma discharge will be shorter, so plasma treatment with hydrogen gas containing a silicon atom-containing gas that is not substantially deposited. The effect of is less likely to appear.

In the hydrogen plasma processing method of the present invention,
The amount of the silicon atom-containing gas added to the hydrogen gas is preferably 0.001% to 0.1%.
The amount of silicon atom-containing gas added to hydrogen gas is
If it is less than 0.001%, the effect of the present invention will not appear, and if it is more than 0.1%, the deposition of silicon atoms will increase, and the original effect of hydrogen plasma treatment will not appear.

The energy suitable for generating the hydrogen plasma of the present invention is an electromagnetic wave, among which RF (r
adio frequency), VHF (very)
high frequency), MW (microrow)
ave) is a suitable energy. When the hydrogen plasma treatment of the present invention is performed by RF, the preferable frequency range is
It is in the range of 1 MHz to 50 MHz. When the hydrogen plasma treatment of the present invention is performed by VHF, a preferable frequency range is 51 MHz to 500 MHz. When the hydrogen plasma treatment of the present invention is performed in MW, the preferable frequency range is 0.51 GHz to 10 GHz.

In order to effectively carry out the hydrogen plasma treatment of the present invention, the degree of vacuum is an important factor, and the preferable range is the energy used for activating the hydrogen gas added with the silicon atom-containing gas. Greatly depends on. When the hydrogen plasma treatment is performed in the RF frequency band, the preferred vacuum degree is in the range of 0.05 Torr to 10 Torr. When performing the hydrogen plasma treatment in the VHF frequency band, the preferred vacuum degree is in the range of 0.0001 Torr to 1 Torr. A preferable degree of vacuum when hydrogen plasma treatment is performed in the MW frequency band is 0.0001T.
The range is from orr to 0.01 Torr.

In the hydrogen plasma treatment of the present invention, the power density introduced into the chamber for producing hydrogen plasma is an important factor for effectively performing the hydrogen plasma treatment of the present invention. Such power density depends on the frequency of the electromagnetic wave used. When using the RF frequency band, the power density is 0.01 to 1
W / cm ³ is a preferred range. When using the VHF frequency band, 0.01 to 1 W / cm ³ is a preferable range. Particularly in the VHF frequency band, there is a feature that plasma discharge can be maintained in a wide pressure range, and when performing hydrogen plasma treatment at high pressure, it is preferable to perform hydrogen plasma treatment at a relatively low power density. On the other hand, when performing hydrogen plasma treatment at a low pressure,
It is preferable to carry out at a relatively high power density.
When the hydrogen plasma treatment of the present invention is performed using the MW frequency band, 0.1 to 10 W / cm ³ is a preferable power density range. In carrying out the hydrogen plasma treatment of the present invention, there is a close relationship between the power density and the hydrogen plasma treatment time, and when the power density is high, it is preferable that the hydrogen plasma treatment time is relatively short. is there.

In the hydrogen plasma treatment of the present invention, the substrate temperature during the hydrogen plasma treatment is a very important factor for making the effect of the present invention effective. When hydrogen plasma processing is performed using the RF frequency band, it is preferable that the substrate temperature is relatively high. 100 to 4
00 ° C is the preferred temperature range. When the hydrogen plasma treatment of the present invention is performed using the VHF or MW frequency band, the substrate temperature is preferably a relatively low temperature. In this case, 50 to 300 ° C. is a preferable temperature range. Further, the substrate temperature during the hydrogen plasma treatment of the present invention closely depends on the power density input into the chamber, and when the input power density is relatively high, the substrate temperature should be low. Is preferred.

When performing the hydrogen plasma treatment of the present invention, the power density, gas flow rate, substrate temperature, pressure, etc.
It may be changed with respect to the processing time. Usually, the substrate has many defects and many impurities near the surface. Therefore, it is preferable that the hydrogen plasma treatment is performed at a relatively high power density and a high pressure at the start of the treatment.

In the hydrogen plasma treatment of the present invention, the silicon atom-containing gas added to the hydrogen gas is Si.
H ₄ , Si ₂ H ₆ , SiF ₄ , SiF ₃ H, SiF ₂ H ₂ , S
iF ₃ H, Si ₂ FH ₅ , SiCl ₄ , SiClH ₃ , Si
Suitable are silicon hydride compounds or halogenated silicon compounds such as Cl ₂ H ₂ , SlClH ₃ . These silicon atom-containing gases may be added alone to the hydrogen gas, or a plurality of them may be added in combination. In particular, the mixing ratio of the silicon atom-containing gas containing halogen atoms is preferably larger than that of the silicon atom-containing gas containing no halogen atoms.

(Forming Method and Apparatus) A method of forming the photovoltaic element of the present invention and a forming apparatus suitable for the method will be described. An example of the forming apparatus is shown in the schematic explanatory view of FIG.

In FIG. 4, the forming apparatus 400 includes a load chamber 401 and transfer chambers 402, 403, 40.
4, unload chamber 405, gate valve 40
6, 407, 408, 409, substrate heating heater 41
0, 411, 412, a substrate transfer rail 413, an n-type layer (or p-type layer) deposition chamber 417, an i-type layer deposition chamber 418, a p-type layer (or n-type layer) deposition chamber 419, a plasma forming cup 420. , 421, power sources 422, 423, 424, microwave introduction window 425,
Waveguide 426, gas introduction pipes 429, 449, 469, valves 430, 431, 432, 433, 434, 44.
1, 442, 443, 444, 450, 451, 45
2,453,454,455,461,462,46
3, 464, 465, 470, 471, 472, 47
3, 474, 481, 482, 483, 484, mass flow controllers 436, 437, 438, 439,
456, 457, 458, 459, 460, 476, 4
77, 478, 479, a shutter 427, a bias rod 428, a substrate holder 490, an exhaust device (not shown), a microwave power source (not shown), a vacuum gauge (not shown), a controller (not shown), and the like.

The method of forming a photovoltaic element to which the hydrogen plasma processing method of the present invention is applied is performed as follows using the forming apparatus shown in FIG.

All chambers of the deposition apparatus 400 are connected to each chamber by a turbo molecular pump (not shown).
The degree of vacuum is raised to 0 ^-6 Torr or less.

When the hydrogen plasma treatment of the present invention is performed by RF, it is performed as follows. A base plate having a reflective layer of silver or the like vapor-deposited on a stainless support and a reflection-increasing layer of zinc oxide or the like is vapor-deposited on the base plate holder 490. The substrate holder 490 is put in the load chamber 401. The door of the load chamber 401 is closed, and the load chamber 401 is pulled up to a predetermined vacuum degree by a mechanical booster pump / rotary pump (MP / RP) not shown. When the load chamber reaches a predetermined vacuum degree, the MP / RP is switched to a turbo molecular pump to raise the vacuum degree to 10 ^-6 Torr or less. Load chamber is 10 ^-6 Torr
When the degree of vacuum reaches the following level, the gate valve 406 is opened, the substrate holder 490 on the substrate transfer rail 413 is moved to the transfer chamber 402, and the gate valve 406 is moved.
Close. The substrate heating heater 410 of the transfer chamber 402 is raised so that the substrate holder 490 does not hit it. Position the substrate holder so that the substrate is directly under the heater. The heater 410 for heating the substrate is lowered, and the substrate is placed in the n-type layer deposition chamber.

The substrate temperature is changed to a temperature suitable for depositing the n-type layer, and a silicon atom-containing gas such as SiH ₄ , Si ₂ H ₆ for depositing the n-type layer and the periodic table V for depositing the n-type layer. Gas containing group element valve 443, mass flow controller 43
8. Introduce into the deposition chamber 417 via the valve 433. Further, it is preferable that the flow rate of hydrogen gas is also appropriately adjusted according to the n-type layer. In this way, the source gas for n-type layer deposition is introduced into the deposition chamber 417, and the opening / closing degree of the exhaust valve (not shown) is changed to bring the inside of the deposition chamber 417 to a desired vacuum degree of 0.1 to 10 Torr. Then, the RF power source 422 transfers the RF to the plasma forming cup 420.
Power is introduced, plasma discharge is generated, and the discharge is maintained for a desired time. In this way, an n-type semiconductor layer is deposited on the substrate to a desired thickness.

The hydrogen plasma treatment of the present invention on the n-type layer is performed as follows. A hydrogen gas and a silicon atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention are provided in the chamber through valves 441 and 442, mass flow controllers 436 and 437, valves 431 and 432, and valve 429 at a predetermined flow rate to deposit chamber 417.
To introduce. The degree of opening and closing of an exhaust valve (not shown) is changed to make the inside of the deposition chamber 417 have a desired vacuum degree. Chamber 41
When the degree of vacuum of 7 is stabilized, RF power is introduced from the RF power source 422 into the plasma forming cup 420 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time.

Depending on the surface condition of the substrate and the condition of the inner wall of the chamber, the flow rate of hydrogen gas, the flow rate of gas containing silicon atoms, the RF power,
It is desirable to appropriately change the substrate temperature and the like. The preferred forms of change in these parameters are:
Initially, the hydrogen flow rate is increased and the hydrogen flow rate is decreased over time. As a form of change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is initially small and the flow rate of the silicon atom-containing gas increases with time. The RF power is a form of change in which it is preferable that the RF power is initially high and then becomes low over time.

In this way, the n-type layer in contact with the substrate is deposited, and after the hydrogen plasma treatment of the present invention is performed, the supply of the source gas to the deposition chamber 417 is stopped by closing a predetermined valve, and the deposition is performed. Helium gas for purging chamber 417 valve 444, mass flow controller 43
9. The deposition chamber 417 was purged by introducing it into the deposition chamber 417 through the valve 434. The supply of helium gas to the deposition chamber 417 is stopped, and the inside of the chamber is evacuated by a turbo molecular pump. At the same time, the heater 410 for heating the substrate is raised so that the substrate can be transported.

Deposition chamber 417 with turbo molecular pump
When the inside becomes 10 ⁻⁶ Τorr or less, the gate valve 407 is opened and the substrate holder 490 is placed in the transfer chamber 4.
02 to the transfer chamber 403. The substrate holder 490 is moved so that the substrate is directly below the substrate heating heater 411. The substrate heating heater 411 is lowered to bring the substrate into contact with the heater. Then, the substrate temperature is heated to a predetermined temperature. Open a valve 461 for an inert gas such as hydrogen gas or helium gas, set a desired flow rate with a mass flow controller, and set valves 451 and 45.
It is preferable to heat the substrate while opening 0 and flowing. The vacuum degree at that time is preferably the same as that at the time of depositing the n / i buffer layer.

When the substrate temperature reaches the desired temperature, the gas for heating the substrate is stopped, and the source gas for n / i buffer layer deposition is supplied from the gas supply device to the deposition chamber 418. For example, hydrogen gas, silane gas, germane gas,
The valves 462, 463, and 464 are opened, the mass flow controllers 457, 458, and 459 are set to desired values, and the valves 452, 453, 454, and 450 are opened, and the gas is supplied to the deposition chamber 418 through the gas introduction pipe 449. At the same time, the supply gas is evacuated by a diffusion pump (not shown) so that the vacuum degree of the deposition chamber 418 becomes a desired pressure. When the degree of vacuum in the chamber 418 becomes stable at the desired degree of vacuum, a desired power is introduced from an RF power source (not shown) to the bias rod for applying the bias. Then, an n / i buffer layer is deposited by the RF plasma CVD method. n / i
The buffer layer is preferably deposited at a slower deposition rate than the i-type layer deposited thereafter. n / i
After the buffer layer is deposited to a predetermined thickness, the RF power supply is stopped and the RF plasma CVD is completed.

Subsequently, the source gas is changed to a flow rate for i-type layer deposition, and the degree of vacuum in the deposition chamber is set to a predetermined degree of vacuum.
Adjust with a pressure adjusting valve (not shown). After the pressure in the deposition chamber is stabilized, desired power is introduced into the deposition chamber 418 from a microwave power source (not shown) through the waveguide 426 and the microwave introduction window 425. Simultaneously with the introduction of microwave energy, it is also preferable to introduce a desired bias power into the deposition chamber 418 from an external DC, RF or VHF power supply 424 to the biasing bias rod as shown in an enlarged view of the deposition chamber 418. It is a thing.
In this way, the i-type layer is deposited to a desired layer thickness. When the i-type layer can be deposited to a desired layer thickness, the application of microwave power and bias is stopped, and further the source gas supplied to the deposition chamber is stopped.

Thereafter, a p / i buffer layer is deposited to a desired layer thickness in the same manner as the n / i buffer layer is deposited. Then, if necessary, the inside of the deposition chamber 418 is purged with an inert gas such as hydrogen gas or helium gas. Change the exhaust from diffusion pump to turbo molecular pump,
The degree of vacuum in the deposition chamber is set to 10 ^-6 Torr or less. At the same time, raise the heater for heating the substrate so that the substrate holder can move.

The gate valve 408 is opened, the substrate holder is moved from the transfer chamber 403 to the transfer chamber 404, and the gate valve 408 is closed. The substrate holder is moved right below the heater 412 for heating the substrate, and the substrate is heated by the heater 412 for heating the slope. It is a more preferable form that the exhaust gas is changed from the turbo molecular pump to MP / RP and the substrate is heated by flowing an inert gas such as hydrogen gas or helium gas at a pressure at the time of deposition of the p-type layer during heating. is there. When the substrate temperature stabilizes at the desired substrate temperature, the supply of the substrate heating gas such as the hydrogen gas or the inert gas for heating the substrate is stopped, and the source gas for p-type layer deposition, such as H ₂ ,
In the case of SiH ₄ and p-type layer, a valve containing the group III element containing gas such as BF ₃ is opened in valves 482, 483 and 484,
The valves 472, 473, 474 are further opened via the mass flow controllers 477, 478, 479 to supply the desired flow rate to the deposition chamber 419 through the gas introduction pipe 469. The exhaust valve is adjusted so that the internal pressure of the deposition chamber 419 becomes a desired degree of vacuum. When the internal pressure of the deposition chamber 419 becomes stable at a desired degree of vacuum, the RF power source 423 supplies RF power to the plasma forming cup. Then, the p-type layer is deposited by depositing for a desired time.

After the completion of the deposition, the supply of the RF power and the source gas is stopped and the inside of the deposition chamber is sufficiently purged with an inert gas such as hydrogen gas or helium gas. After purging, change exhaust from MP / RP to turbo molecular pump
Evacuate to a vacuum degree of 0 ^-6 Torr or less. At the same time, the heater 412 for heating the substrate is raised, the gate valve 409 is opened, and the substrate holder 490 is moved to the unload chamber 4
Move to 05. The gate valve 409 is closed, and when the temperature of the substrate holder becomes 100 ° C. or lower, the door of the unload chamber is opened and the substrate is taken out.

In this way, the pin semiconductor layer is formed on the substrate. The substrate on which the pin semiconductor layer is formed is set in a vacuum vapor deposition device for depositing a transparent electrode to form a transparent electrode on the semiconductor layer. Next, the photovoltaic element with the transparent electrode formed,
The photovoltaic element is formed by setting the collector electrode in a vacuum evaporator for depositing the collector electrode.

When the hydrogen plasma treatment of the present invention is performed by MW, it is performed as follows. After depositing the n-type layer on the substrate, the gate valve 407 is opened and the substrate holder 490 is opened.
The gate valve 40.
Close 7. The position of the substrate holder is determined so that the substrate is directly below the heater 411. The heater 411 for heating the substrate is lowered, and the substrate is placed in the i-type layer deposition chamber. The substrate heating heater 411 raises the substrate temperature to a desired substrate temperature. The turbo molecular pump is switched to MP / RP, and the hydrogen gas and the silicon atom-containing gas necessary for performing the hydrogen plasma treatment of the present invention are introduced into the chamber by the valve 46.
1, 462, mass flow 456, 457, valve 45
1, a predetermined flow rate is introduced into the deposition chamber 418 via the valve 450. The degree of opening and closing of an exhaust valve (not shown) is changed to bring the inside of the deposition chamber 418 to a desired vacuum degree.
When the degree of vacuum in the chamber 418 becomes stable, MW power is introduced from a MW power source (not shown) into the deposition chamber 418 through the microwave introduction window 425 to generate plasma. Thus, the hydrogen plasma treatment of the present invention is performed for a predetermined time.

Depending on the surface condition of the substrate and the condition of the inner wall of the chamber, the hydrogen gas flow rate, the silicon atom-containing gas flow rate, the MW power, and
It is desirable to appropriately change the substrate temperature and the like. The preferred forms of change in these parameters are:
Initially, the hydrogen flow rate is increased and the hydrogen flow rate is decreased over time. As a form of change in the flow rate of the silicon atom-containing gas, the flow rate of the silicon atom-containing gas is small at first and the flow rate of the silicon atom-containing gas increases with time. The MW power is a form of change in which it is preferable that the MW power is initially high and then becomes low over time. When the hydrogen plasma treatment of the present invention is performed by VHF, it is preferable that the hydrogen plasma treatment is performed in the same manner as in the case of MW.

Further, it is also preferable that the vicinity of the interface between the substrate and the n-type layer is also subjected to hydrogen plasma treatment with hydrogen gas containing a silicon atom-containing gas in an amount that does not substantially deposit. In order to perform the hydrogen plasma treatment in the vicinity of the interface between the substrate and the n-type layer, the substrate is transferred to the n-type layer deposition chamber or the i-type layer deposition chamber in the above procedure, and the substrate is kept at a predetermined substrate temperature. The silicon atom-containing gas and the hydrogen gas are introduced into the deposition chamber at a predetermined flow rate according to the above procedure. The pressure is adjusted by the pressure adjusting valve so that the degree of vacuum is suitable for the type of introduced power such as RF, VHF or / and MW power. RF, VHF or / and MW power is introduced to cause plasma discharge, and the hydrogen plasma treatment of the present invention is performed on the substrate for a predetermined time.

In the above-described method for forming a photovoltaic element for carrying out hydrogen plasma treatment of the present invention, the gas cylinder may be used by appropriately exchanging it with a necessary gas cylinder. In that case, it is preferable that the gas line be sufficiently heated and purged.

A photovoltaic element in which a plurality of pin semiconductor layers are laminated is formed by depositing a desired number of times in an n-type layer deposition chamber, an i-type layer deposition chamber, and a p-type layer deposition chamber of the forming apparatus 400. Is something that can be done.

Next, the components of the photovoltaic element will be described in detail.

(Substrate) The material of the support preferably used in the present invention is one that has little deformation and distortion at the temperature required for forming the deposited film, has the desired strength, and has conductivity. It is preferable that the support is one in which the adhesion of the reflective layer or the reflection increasing layer to the support is not deteriorated by the hydrogen plasma treatment of the present invention performed after depositing the reflection layer or the reflection increasing layer. .

Specifically, thin films of metals such as stainless steel, aluminum and its alloys, iron and its alloys, copper and its alloys, and composites thereof, and metal thin films of different materials and / or SiO _{2 on} their surfaces, Si ₃ N ₄ , Al ₂
An insulating thin film of O ₃ , AlN or the like, which has been subjected to surface coating treatment by a sputtering method, a vapor deposition method, a plating method or the like, or a heat-resistant resinous sheet of polyimide, polyamide, polyethylene terephthalate, epoxy or the like or glass fiber with these, Carbon fibers, boron fibers, metal fibers or the like, on the surface of which a simple metal or alloy, and a transparent conductive oxide or the like have been subjected to a conductive treatment by a method such as plating, vapor deposition, sputtering or coating. .

Further, the thickness of the support is within the range where the curved shape formed when the support is moved is maintained and the strength is maintained as much as possible in consideration of cost, storage space and the like. It is desirable to be thin. Specifically, it is preferably 0.01 mm to 5 mm, more preferably 0.02.
The thickness is preferably 2 mm to 2 mm, and more preferably 0.05 mm to 1 mm, but when a thin film of metal or the like is used, the desired strength can be easily obtained even if the thickness is relatively thin.

The width of the support is not particularly limited and is determined by the size of the vacuum container and the like.

The length of the above-mentioned support is not particularly limited, and even if it is such a length that it can be wound into a roll, a long one is further lengthened by welding or the like. It may be.

In the present invention, the support is heated and cooled in a short time, but it is not preferable that the temperature distribution spreads in the longitudinal direction of the support. Therefore, it is desirable that the heat conduction in the moving direction of the support is small. In order for the surface temperature to follow heating and cooling, it is preferable that the heat conduction is large in the thickness direction.

The heat conduction of the support is reduced in the moving direction by a small thickness.
In order to increase in the direction, the thickness can be reduced.
Is uniform, the (heat conduction) x (thickness) is preferably 1 x
10 ^-1W / K or less, more preferably 0.5 × 10^-1W /
It is preferably K or less.

(Reflective layer) As the material of the reflective layer, Ag,
Au, Pt, Ni, Cr, Cu, Al, Ti, Zn, M
Examples thereof include metals such as o and W or alloys thereof, and thin films of these metals are formed by vacuum vapor deposition, electron beam vapor deposition, sputtering or the like. In addition, care must be taken so that the formed metal thin film does not become a resistance component to the output of the photovoltaic element, and the sheet resistance value of the reflective layer is preferably 50Ω or less, more preferably 10Ω or less. Is desirable.

When the support is transparent and the photovoltaic element is irradiated with light from the transparent support, it is preferable to form a transparent conductive layer instead of the reflective layer. It is a thing. As a transparent conductive layer suitable for such a purpose, tin oxide, indium oxide, an alloy thereof, or the like is suitable. Further, it is preferable that the light-transmissive conductive layer is deposited so as to satisfy the antireflection condition. The sheet resistance of these translucent conductive layers is preferably 50Ω or less, more preferably 10Ω.
The following is desirable.

(Reflection Increasing Layer) The reflection increasing layer preferably has a light reflectance of 85% or more in order to efficiently absorb the reflected light from the substrate that has passed through the reaction body layer into each semiconductor layer. Further, electrically, the sheet resistance value is preferably 100Ω or less so as not to become a resistance component with respect to the output of the photovoltaic element. Materials having such characteristics include SnO ₂ , In ₂ O ₃ , ZnO, CdO, and Cd ₂ SnO.
₄ , metal oxides such as ITO (In ₂ O ₃ + SnO ₂ ) and the like. In the photovoltaic device, the reflection enhancing layer is laminated in contact with the p-type layer or the n-type layer, and it is necessary to select a layer having good mutual adhesion. Further, it is preferable that the reflection increasing layer is deposited in a layer thickness that meets the conditions for increasing the reflection. As a method for forming the reflection increasing layer, a resistance heating vapor deposition method, an electron beam heating vapor deposition method, a sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

(I-type layer) Especially in a photovoltaic element using a group IV or group IV alloy amorphous semiconductor material, p
The i-type layer used for in-junction is an important layer for generating and transporting carriers with respect to irradiation light. For the i-type layer, only p
Type, slightly n-type layers can also be used. Hydrogen atoms (H, D) or halogen atoms (X) are contained in the amorphous semiconductor material, and this has an important function.

The hydrogen atom (H, D) or halogen atom (X) contained in the i-type layer serves to compensate dangling bonds in the i-type layer, and the carrier in the i-type layer. It improves the product of the mobility and the life of the. Also p
A layer having an effect of compensating for the interface state of each interface of the n-type layer / i-type layer and the n-type layer / i-type layer, and having an effect of improving the photovoltaic power, the photocurrent and the photoresponsiveness of the photovoltaic element. Is. The number of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to
The optimum content is 40 at%. In particular, p
A preferable distribution form is one in which the content of hydrogen atoms and / or halogen atoms is largely distributed on each interface side of the n-type layer / i-type layer and the n-type layer / i-type layer, and hydrogen near the interface is mentioned. The content of atoms and / or halogen atoms is preferably in the range of 1.1 to 2 times the content in the bulk. Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed corresponding to the content of silicon atoms.

When the photovoltaic element of the present invention has a plurality of pin structures, it is preferable that the layers are laminated so that the band gap of the i-type layer becomes smaller from the light incident side. Amorphous silicon or amorphous silicon carbide is used for the i-type layer having a relatively wide bandgap, and amorphous silicon germanium is used for the i-type semiconductor layer having a relatively narrow bandgap. Amorphous silicon and amorphous silicon germanium are a-Si: H, a-Si: F, a depending on the element that compensates for the dangling bond.
-Si: H: F, a-SiGe: H, a-SiGe:
It is written as F, a-SiGe: H: F, or the like.

More specifically, for example, as a pin junction i-type semiconductor layer suitable for the photovoltaic element of the present invention,
i-type hydrogenated amorphous silicon (a-Si: H) may be mentioned, and its characteristics include an optical band gap (Eg).
Is 1.60 eV to 1.85 eV, the content (CH) of hydrogen atoms is 1.0 to 25.0%, AM1.5, 100.
Photoconductivity (σp) under mW / cm ² irradiation with pseudo sunlight
, 1.0 × 10 ⁻⁵ S / cm or more, dark conductivity (σd)
, 1.0 × 10 ⁻⁹ S / cm or less, the gradient of the arback tail by the constant photocurrent method (CPM) is 55 meV or less, and the localized level density is 10 ¹⁷ / cm.
Those of ³ or less are preferable.

The amorphous silicon germanium semiconductor material, which constitutes the i-type semiconductor layer having a relatively narrow bandgap of the photovoltaic element of the present invention, has a characteristic optical bandgap (Eg) of 1.20 eV. ~ 1.60e
The content of V and hydrogen atoms (CH) is 1.0 to 25%, the slope of the arback tail by the constant photocurrent method (CPM) is 55 meV or less, and the localized level density is 10 ¹⁷ cm ³ or less. Are preferred.

The i-type layer suitable for the present invention is preferably deposited under the following conditions. The amorphous semiconductor layer is preferably deposited by RF, VHF or MW plasma CVD method.

When depositing by the RF plasma CVD method, the substrate temperature is 100 to 350 ° C., the vacuum degree in the deposition chamber is 0.05 to 10 Torr, and the RF frequency is 1 to 50 MHz. Especially RF frequency is 1
3.56 MHz is suitable. The RF power applied to the deposition chamber is preferably in the range of 0.01 to 5 W / cm ² . Further, the self-bias applied to the substrate by the RF power is preferably in the range of 0 to 300.

In the case of depositing by the VHF plasma CVD method, the substrate temperature is 100 to 450 ° C., the vacuum degree in the deposition chamber is 0.0001 to 1 Torr, and the VHF frequency is 6.
A suitable range is 0 to 500 MHz. In particular, 100 MHz is suitable for the VHF frequency. Further, the VHF power supplied to the deposition chamber is preferably in the range of 0.01 to 1 W / cm ³ . In addition, the self bias applied to the substrate by the VHF power is preferably in the range of 10 to 1000V. Further, the characteristics of the deposited amorphous film are improved by introducing a DC or RF into the deposition chamber by providing a bias rod on top of VHF or separately. When introducing a DC bias using a bias rod,
It is preferred that the bias rod be positive. When the DC bias is introduced to the substrate side, it is preferable to introduce the DC bias so that the substrate side becomes the negative electrode. When introducing RF bias, RF is more than substrate area
It is preferable to reduce the area of the electrode into which is introduced.

When depositing by the MW plasma CVD method, the substrate temperature is 100 to 450 ° C., the vacuum degree in the deposition chamber is 0.0001 to 0.05 Torr, and the MW frequency is 501 MHz to 10 GHz. . 2.45 GHz is particularly suitable for the MW frequency. The MW power input into the deposition chamber is 0.01 to 1 W / c.
m ³ is a suitable range. The MW power is optimally introduced into the deposition chamber with a waveguide. In addition to the MW, a bias rod is separately provided, and DC or RF is introduced into the deposition chamber to improve the characteristics of the deposited amorphous film. If the DC bias is introduced using a bias rod, it is preferred that the bias rod be positive. When the DC bias is introduced to the substrate side, it is preferable to introduce the DC bias so that the substrate side becomes the negative electrode. When introducing the RF bias, it is preferable to make the area of the electrode for introducing the RF smaller than the area of the substrate.

Silane source gas such as SiH ₄ , Si ₂ H ₆ , SiH ₄ and SiF ₂ H ₂ is suitable for depositing the i-type layer suitable for the plasma treatment of the present invention. Further, in order to widen the band gap, it is preferable to add carbon, nitrogen or an oxygen-containing gas. The carbon, nitrogen, or oxygen-containing gas is not contained in the i-type layer uniformly,
It is preferable to add a large amount in the vicinity of the mold layer and / or the n-type layer. By doing so, the open circuit voltage can be improved without alienating the charge running property in the i-type layer. As the carbon-containing gas, C
_n H _{2n + 2} , C _n H _2n , C ₂ H _{2 and the} like are suitable. The nitrogen-containing _{gas, N 2, NO, N 2} 0, NO 2, NH 3 or the like are suitable. O ₂ , CO ₂ , O _3, etc. are suitable as the oxygen-containing gas. Also, a combination of a plurality of these gases may be introduced. A suitable amount of the source gas added to increase the band gap is 0.1 to 50%.

Further, the characteristics of the i-type layer are improved by adding an element of group III or / and group V of the periodic table. The Group III elements of the periodic table are B,
Al, Ga, etc. are suitable. In particular, when B is added, it is preferable to add it by using a gas such as B ₂ H ₆ or BF ₃ . Further, as the Group V element of the periodic table,
N, P, As and the like are suitable. Particularly when P is added, PH ₃ is mentioned as a suitable one. The suitable amount of the group III element and / or the group V element of the periodic table added to the i-type layer is 0.1 to 1000 ppm.

For the i-type layer, the n / i buffer layer and p
By providing the / i buffer layer, the characteristics of the photovoltaic element are improved. As the buffer layer,
A semiconductor layer similar to the i-type layer can be used, in particular i
It is preferable to deposit at a slower deposition rate than the mold layer. A semiconductor having a wider bandgap than the i-type layer is suitable for the buffer layer. The band gap is
It is preferable that it is smoothly continuous from the i-type layer to the buffer layer. As a method for continuously changing the bandgap in the buffer layer, the bandgap can be narrowed by increasing the content of germanium atoms contained in the silicon-based non-single-crystal semiconductor. On the other hand, the band gap can be continuously widened by increasing the content of carbon atoms, oxygen atoms and / or nitrogen atoms contained in the silicon-based non-single crystal semiconductor. The ratio of the narrowest band gap to the widest band gap is 1.01 to 1.
A preferred range is 5.

When an element of Group III or / and Group V of the periodic table is added to the buffer layer, an element of Group III of the periodic table is added to the n / i buffer layer to add p / i.
It is preferable to add a Group V element of the periodic table to the buffer layer. By doing so, it is possible to prevent deterioration of characteristics due to diffusion of impurities from the n-type layer and / or the p-type layer into the i-type layer.

(N-type layer, p-type layer) The p-type layer or the n-type layer is also an important layer that influences the characteristics of the photovoltaic device of the present invention. Examples of the amorphous material of the p-type layer or the n-type layer (denoted as a−) (microcrystalline material (denoted as μc−) also fall into the category of amorphous materials) are, for example, a-Si: H, a-Si: HX, a-SiC: H,
a-SiC: HX, a-SiGe: H, a-SiGe
C: H, a-SiO: H, a-SiN: H, a-SiO
N: HX, a-SiOCN: HX, μc-Si: H, μ
c-SiC: H, μc-Si: HX, μc-SiC: H
X, μc-SiGe: H, μc-SiO: H, μc-S
iGeC: H, μc-SiN: H, μc-SiON: H
X, μc-SiOCN: HX, etc., p-type valence electron control agent (Group III atom B, Al, Ga, In, TI of the periodic table)
And n-type valence electron control agents (group V atoms P, As,
A material to which Sb, Bi) is added at a high concentration can be cited, and a polycrystal material (indicated as poly-) is, for example, po.
ly-Si: H, poly-Si: HX, poly-S
iC: H, poly-SiC: HX, poly-SiG
e: H, poly-Si, poly-SiC, poly
-SiGe, p-type valence electron control agent (periodic table III
Group atom B. Examples of the material include Al, Ga, In, Tl) and an n-type valence electron control agent (atoms P, As, Sb, Bi of Group V of the periodic table) in high concentration.

Particularly, in the p-type layer or the n-type layer on the light incident side,
A crystalline semiconductor layer with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable.

The amount of Group III atoms added to the p-type layer and the amount of Group V atoms added to the n-type layer were 0.1.
The optimum amount is ˜50 at%.

Hydrogen atoms (H, D) or halogen atoms contained in the p-type layer or the n-type layer serve to compensate dangling bonds in the p-type layer or the n-type layer, and thus the p-type layer or the n-type layer. To improve the doping efficiency. Hydrogen atoms or halogen atoms added to the p-type layer or the n-type layer are 0.
The optimum amount is 1 to 40 at%. Especially when the p-type layer or the n-type layer is crystalline, the optimum amount of hydrogen atoms or halogen atoms is 0.1 to 8 at%. Further, a preferable distribution form is one in which the content of hydrogen atoms and / or halogen atoms is largely distributed on the interface side of each of the p-type layer / i-type layer and the n-type layer / i-type layer. The content of hydrogen atoms and / or halogen atoms is preferably in the range of 1.1 to 2 times the content in the bulk. In this way, p-type layer / i-type layer, n-type layer / i
By increasing the content of hydrogen atoms or halogen atoms in the vicinity of each interface of the mold layer, the defect level and mechanical strain in the vicinity of the interface can be reduced, and the photovoltaic power and light of the photovoltaic device of the present invention can be reduced. The current can be increased.

Regarding the electrical characteristics of the p-type layer and the n-type layer of the photovoltaic element, the activation energy is preferably 0.2 eV or less, and most preferably 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less, and most preferably 1 Ωcm or less. Furthermore, the layer thickness of the p-type layer and the n-type layer is 1 to
50 nm is preferable and 3 to 10 nm is optimum.

In order to form a group IV and group IV alloy-based amorphous semiconductor layer suitable as the semiconductor layer of the photovoltaic element of the present invention, the most preferable manufacturing method is microwave plasma CV.
D (MWPCVD) method, and the next preferred manufacturing method is R
This is an F plasma CVD (RFPCVD) method.

In the microwave plasma CVD method, a material gas such as a source gas and a diluting gas is introduced into the deposition chamber,
While evacuating with a vacuum pump, the internal pressure of the deposition chamber was kept constant, and microwaves oscillated by a microwave power source were guided by a waveguide and introduced into the deposition chamber through a dielectric window (alumina ceramics etc.). A plasma of material gas is generated and decomposed to form a desired deposited film on the substrate placed in the deposition chamber, and a deposited film applicable to a photovoltaic device is formed under a wide range of deposition conditions. be able to.

As a source gas suitable for depositing the group IV and group IV alloy-based amorphous semiconductor layers suitable for the photovoltaic element of the present invention, a gasifiable compound containing a silicon atom, germanium atom, is used. A gasifiable compound containing,
A gasifiable compound containing a carbon atom, a compound preliminarily gasifying containing a nitrogen atom, a gasifiable compound containing an oxygen atom, and the like, and a mixed gas of the compounds can be used.

A chain-like or cyclic silane compound is specifically used as a gasifying compound containing a silicon atom. Specific examples include SiH ₄ , Si ₂ H ₆ and Si.
F ₄ , SiFH ₃ , SiF ₂ H ₂ , SiF ₃ H, Si ₃ H ₈ ,
SiD ₄ , SiHD ₃ , SiH ₂ D ₂ , SiH ₃ D, SiF
D ₃ , SiF ₂ D ₂ , SiD ₃ H, Si ₂ D ₃ H ₃ , (Si
F ₂ ) ₅ , (SiF ₂ ) ₆ , (SiF ₂ ) ₄ , Si ₂ F ₆ , Si
₃ F ₈ , Si ₂ H ₂ F ₄ , Si ₂ H ₃ F ₃ , SiCl ₄ , (Si
Cl ₂ ) ₅ , SiBr ₄ , (SiBr ₂ ) ₅ , Si ₂ Cl ₆ ,
SiHCl ₃ , SiH ₂ Br ₂ , SiH ₂ Cl ₂ , Si ₂ Cl
Examples thereof include those in a gas state such as ₃ F ₃ or those which can be easily gasified.

Specifically, a gas containing germanium atoms
GeH is a compound that can be converted into_Four, GeD_Four, GeF_Four,
GeFH₃, GeF₂H₂, GeF₃H, GeHD₃, Ge
H₂D ₂, GeH₃D, Ge₂H₆, Ge₂D₆Etc.
It

Can be gasified specifically containing carbon atoms
As the compound, CH_Four, CD_Four, C _nH_{2n + 2}(N is an integer
Number), C_nH_2n(N is an integer), C₂H₂, C₆H₆, CO₂,
CO etc. are mentioned.

As the nitrogen-containing gas, N ₂ , NH ₃ , N
D ₃ , NO, NO ₂ and N ₂ O can be mentioned. Oxygen-containing gas includes O ₂ , CO, CO ₂ , NO, NO ₂ , N ₂ O, CH
₃ CH ₂ OH, CH ₃ OH, etc. are struck.

Further, examples of the substance introduced into the p-type layer or the n-type layer for controlling the valence electrons include Group III atoms and Group V atoms of the periodic table.

The materials effectively used as a starting material for introducing a Group III atom include B ₂ H ₆ , B ₄ H ₁₀ , B ₅ H ₉ and B ₅ specifically for introducing a boroso atom. H ₁₁ , B ₆
Hydrogenated borohydride such as H ₁₀ , B ₆ H ₁₂ , B ₆ H ₁₄ , BF ₃ , B
Examples thereof include halogenated halo such as Cl ₃ .
In addition, AlCl ₃ , GaCl ₃ , InCl ₃ , TlC
Examples include l _{3 and the} like. In particular, B ₂ H ₆ and BF ₃ are effectively used as a suitable starting material for introducing a Group V atom, specifically, PH ₃ and P ₂ for introducing a phosphorus atom.
H ₄ Phosphorus hydride, PH ₄ I, PF ₃ , PF ₅ , PCl ₃ , P
Examples thereof include phosphorus halides such as Cl ₅ , PBr ₃ , PBr ₅ , and PI ₃ . In addition, AsH ₃ , AsF ₃ , AsCl ₃ , A
sBr ₃ , AsF ₅ , SbH ₃ , SbF ₃ , SbF ₅ , Sb
Other examples include Cl ₃ , SbCl ₅ , BiH ₃ , BiCl ₃ and BiBr ₃ . Particularly, PH ₃ and PF ₃ are suitable.

Further, the gasifiable compound is replaced by H ₂ , H
It may be appropriately diluted with a gas such as e, Ne, Ar, Xe, or Kr and introduced into the deposition chamber. Especially microcrystalline semiconductors and a-Si
When depositing a layer such as C: H that has little light absorption or has a wide band gap, dilute the source gas 2 to 100 times with hydrogen gas and introduce relatively high microwave power or RF power. Is preferred.

(Transparent Electrode) The transparent electrode preferably has a light transmittance of 85% or more in order to efficiently absorb light from the sun, white fluorescent lamp, or the like into each semiconductor layer.
Further, electrically, the sheet resistance value is preferably 100Ω or less so as not to be a resistance component to the output of the photovoltaic element. As a material having such characteristics, S
nO ₂ , In ₂ O ₃ , ZnO, CdO, Cd ₂ SnO ₄ , I
Metal oxides such as TO (In ₂ O ₃ + SnO ₂ ) and A
Examples thereof include a metal thin film in which a metal such as u, Al, or Cu is formed into an extremely thin film in a semitransparent state. The transparent electrode is laminated on the p-type layer or the n-type layer half in the photovoltaic element,
When a photovoltaic element is formed on a translucent support and light is irradiated from the translucent support side, it is laminated on the support, so select ones that have good mutual adhesion. It is necessary. Further, it is preferable that the transparent electrode is deposited in a layer thickness suitable for the antireflection condition. As a method for producing the transparent electrode, a resistance heating vapor deposition method, an electron beam heating vapor deposition method, a sputtering method, a spray method, or the like can be used and is appropriately selected as desired.

(Collecting Electrode) As the collecting electrode of the photovoltaic element subjected to the hydrogen plasma treatment of the present invention, silver paste is formed by screen printing, or Cr, Ag, Au,
It may be formed by vacuum vapor deposition using a mask of Cu, Ni, ΜO, Al or the like. Alternatively, a metal wire of Cu, Au, Ag, Al or the like may be attached with carbon or Ag powder together with a resin and attached to the surface of the photovoltaic element to form a collecting electrode.

When a photovoltaic device having a desired output voltage and output current is manufactured using the photovoltaic device of the present invention, the photovoltaic device of the present invention is connected in series or in parallel, A protective layer is formed on the front and back surfaces, and output extraction electrodes and the like are attached. Further, when the photovoltaic elements of the present invention are connected in series, a diode for preventing backflow may be incorporated.

[0101]

EXAMPLES A method for forming a photovoltaic element of the present invention will be described in detail below with respect to a solar cell made of a non-single crystal silicon semiconductor material, but the present invention is not limited to this.

Example 1 The solar cell of FIG. 1 was produced using the deposition apparatus shown in FIG. First, a substrate was manufactured. A stainless steel support (100) having a thickness of 0.5 mm and 50 × 50 mm ² was ultrasonically cleaned with acetone and isopropanol, and dried with warm air.

On the surface of the stainless support (100) at room temperature by the sputtering method, Ag having a layer thickness of 0.3 μm was used.
Light reflection layer (101) and a layer thickness of 1.0 on it at 350 ° C.
A reflection-increasing layer (102) of ZnO having a thickness of 100 μm was formed, and the fabrication of the substrate was completed.

Next, each semiconductor layer was formed on the reflection increasing layer using the deposition apparatus 400. The deposition apparatus 400 is MWP
Both CVD and RFPCVD methods can be performed.

A source gas cylinder (not shown) is installed in the deposition apparatus.
It is connected through the introduction pipe. Raw gas cylinder Yes
The gap is also refined to ultra-high purity, SiH_FourGas Bon
B, SiF_FourGas cylinder, CH_FourGas cylinder, GeH_FourMoth
Smoke, GeF_FourGas cylinder, Si₂H₆Gas cylinder,
PH₃/ H₂(Dilution: 1000ppm) Gas cylinder, B
₂H₆/ H₂(Dilution: 2000ppm) Gas cylinder, H₂
Gas cylinder, He gas cylinder, SiCl₂H₂Gas Bon
SiH_Four/ H₂(Dilution: 1000ppm) Gas Bon
Connected

Next, the substrate 490 on which the reflection layer 101 and the reflection increasing layer 102 are formed is placed on the substrate transfer rail 413 in the load chamber 401, and the load chamber 401 is pressurized by a vacuum exhaust pump (not shown). Is about 1
It was evacuated to × 10 ^-5 Torr. Next, the gate valve 406 was opened and the film was transferred into the transfer chamber 402 and the deposition chamber 417 which were evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 410 and heated, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) to a pressure of about 1 × 10 ⁻⁵ Torr.

After the preparation for film formation was completed as described above, the RFn type layer 103 made of μc-Si was formed.

An RFn type layer made of μc-Si is formed.
To H₂Gas introduction pipe for introducing gas into the deposition chamber 417
Introduced through 429, H₂Gas flow rate is 200 sccm
Valve 441, 431, 430 so that
It was adjusted with the sflow controller 436. Heap Chang
The pressure inside the bar 417 is not set to 1.2 Torr.
It was adjusted with the conductance valve shown. Substrate 490 temperature
Heat the substrate heater 410 so that the temperature is 360 ° C.
After setting, when the substrate temperature is stable, SiH _Fourgas,
PH₃/ H₂Valve 44 for gas in deposition chamber 417
Operate 3, 433, 444, 434 to operate the gas introduction pipe 42
Introduced through 9. At this time, SiH_FourGas flow rate is 2s
ccm, H₂Gas flow rate is 100 sccm, PH₃/ H₂Moth
Mass flow control so that the flow rate is 200 sccm
Adjust with rollers 438, 436, 439 and
Adjust the pressure inside bar 417 to 1.2 Torr
did. The power of the RF power source 422 is 0.05 W / cm³Set up
RF power to the plasma forming cup 420
Then, a glow discharge is generated to form an RFn type layer on the substrate.
And a RFn type layer having a layer thickness of 20 nm was formed.
Turn off the RF power to stop the glow discharge and turn on the RFn type layer 1
The formation of 03 is completed. Si into the deposition chamber 417
H_FourGas, PH₃/ H₂Stop the flow of water for 5 minutes in the deposition chamber
To H₂After continuing to flow the gas, H₂Also stopped the inflow of
1 × 10 inside and inside gas pipe^-FiveVacuum exhaust to Torr
did.

Next, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed under the conditions shown in Table 1 (1).

Hydrogen plasm containing trace silane-based gas of the present invention
In order to perform processing, as a gas containing silicon atoms,
SiH_Four/ H₂(Dilution: 1000ppm) Gas, H₂Moth
Gas into the deposition chamber 417.
Then introduced, H₂So that the gas flow rate is 750 sccm
Open valves 441, 431, 430 in the
It was adjusted with a controller 436. Silicon atom-containing gas
Is SiH_FourGas amount is all H₂0.04% for gas flow rate
Open the valves 442 and 432 so that
It was adjusted with the controller 437. Deposition chamber 41
The pressure inside 7 is 1.1 Torr
Adjusted with the dactance valve. The temperature of the substrate 490 is 36
Set the substrate heating heater 410 to 0 ° C.,
When the substrate temperature is stable, turn on the power of the RF power source 422.
0.04W / cm³Set to, RF power is introduced, and
Glow discharge is generated in the cup forming cup 420 and 3
Minutes The hydrogen plasma treatment containing trace silane-based gas of the present invention
went. Then turn off the RF power to stop glow discharge,
SiH into the deposition chamber 417_Four/ H₂(Dilution degree: 1
000ppm) stop the flow of gas, 5 minutes,
H into the bar 417 ₂After continuing to flow the gas, H₂Gas flow
Turn off the inside and set the inside of the deposition chamber 417 and the gas pipe.
1x10^-FiveEvacuated to Torr.

Next, the n / i buffer layer 151 made of a-Si, the MWi type layer 104 made of a-SiGe, a-
The p / i buffer layer 161 made of Si is sequentially RFPC
It was formed by the VD method, the MWPCVD method, and the RFPCVD method.

First, the transfer chambers 403 and i which have been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valve 407 was opened into the mold layer deposition chamber 418, and the substrate 490 was transported. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 411 and heated, and the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

To prepare the n / i buffer layer 151
Heat the substrate so that the temperature of the substrate 490 becomes 360 ° C.
The heater 411 is set to make sure that Kisaka is sufficiently heated.
The valves 464, 454, 450, 463, 453.
Gradually open, Si₂H₆Gas, H₂Gas introduction pipe 4
Flow into the i-type layer deposition chamber 418 through 49
It was At this time, Si₂H₆Gas flow rate is 4 sccm, H₂gas
Each mass flow controller should have a flow rate of 100 sccm.
It was adjusted with the control rollers 459 and 458. i-type layer deposition
The pressure inside the chamber 418 will be 0.8 Torr.
Thus, the opening of the conductance valve (not shown) was adjusted.
Next, a high frequency (hereinafter abbreviated as “RF”) power source 424
0.07W / cm³Set to and apply to the bias rod 428
Then, glow discharge is generated and the shutter 427 is opened.
This started the fabrication of the n / i buffer layer on the RF n-type layer
Then, an n / i buffer layer having a layer thickness of 10 nm was prepared.
Stop the RF glow discharge and turn off the output of the RF power supply 424.
The fabrication of the n / i buffer layer 151 was completed. valve
I-type layer deposition chamber 418 with 464, 454 closed.
Si into₂H₆Stop the flow of gas for 2 minutes
H into the chamber 418 ₂After continuing to flow the gas, the valve
453 and 450 are closed, and inside the i-type layer deposition chamber 418
And 1 × 10 in the gas pipe^-FiveEvacuate to Torr
It was

To form the MWi type layer, the substrate heating heater 411 is controlled so that the temperature of the substrate 490 becomes 360 ° C.
The valve 46 when the substrate is sufficiently heated.
1, 451, 450, 462, 452, 463, 453
Is gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas are introduced into the i-type layer deposition chamber 41 through the gas introduction pipe 449.
It was poured into 8.

At this time, the SiH ₄ gas flow rate is 38 scc
m, GeH ₄ gas flow rate is 35 sccm, H ₂ gas flow rate is 1
The mass flow controllers 456, 457, and 458 were adjusted to 20 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 6 mTorr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 was set to 0.60 W / cm ³ and applied to the bias rod 428. After that, the power of the MW power source (not shown) is set to 0.25 W / cm ³ , and the waveguide 426,
And, MW power is introduced into the i-type layer deposition chamber 418 through the microwave introduction window 425 to cause glow discharge, and the shutter 427 is opened to start production of the MWi-type layer on the n / i buffer layer. When the i-type layer having a thickness of 0.15 μm was produced, the MW glow discharge was stopped, the output of the bias power source 424 was cut off, and the production of the MWi-type layer 204 was completed. The valves 451 and 452 are closed to stop the inflow of SiH ₄ gas and GeH ₄ gas into the i-type layer deposition chamber 418 for 2 minutes into the i-type layer deposition chamber 418 with H ₂ gas.
After continuing to flow the gas, close the valves 453 and 450,
1 × in the i-type layer deposition chamber 418 and the gas pipe
It was evacuated to 10 ^-5 Torr.

To fabricate the p / i buffer layer 161, the substrate heating heater 411 is set so that the temperature of the substrate 490 is 250 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, 463. , 453 are gradually opened to introduce Si ₂ H ₆ gas and H ₂ gas into the gas introduction pipe 4
It was made to flow into the i-type layer deposition chamber 418 through 49. At this time, the mass flow controllers 459 and 458 were adjusted so that the Si ₂ H ₆ gas flow rate was ₂ sccm and the H ₂ gas flow rate was 80 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 0.7 Torr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 is set to 0.07 W / cm ³ , a bias rod 428 is applied, a glow discharge is generated, and a shutter 427 is opened to start the production of a p / i buffer layer on the MWi type layer. Then, when the p / i buffer layer having a layer thickness of 20 nm was prepared, the RF glow discharge was stopped, and the RF
The output of the power supply 424 was turned off, and the production of the p / i buffer layer 161 was completed. The valves 464 and 454 are closed to stop the flow of Si ₂ H ₆ gas into the i-type layer deposition chamber 418, and the H ₂ gas is continuously flowed into the i-type layer deposition chamber 418 for 2 minutes, and then the valves 453 and 450. Closed, and the inside of the i-type layer deposition chamber 418 and the gas pipe was set at 1 × 10 ^−5.
Evacuated to Torr.

Next, the RF p-type layer 105 made of a-SiC
Was formed. To form the RF p-type layer 105 made of a-SiC, the gate valve 408 is opened into the transfer chamber 404 and the p-type layer deposition chamber 419 which have been evacuated by a vacuum exhaust pump (not shown) in advance, and the substrate 490 is opened. Transported. The back surface of the substrate 490 is brought into close contact with the substrate heating heater 412 to heat it, and the pressure inside the p-type layer deposition chamber 419 is adjusted to about 1 × by a vacuum exhaust pump (not shown).
It was evacuated to 10 ⁻⁵ Torr.

So that the temperature of the substrate 490 becomes 200 ° C.
Set the substrate heating heater 412 to stabilize the substrate temperature.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂
Gas, CH_FourGas, valve in deposition chamber 419
481, 471, 470, 482, 472, 483, 4
73, 484, 474 by operating the gas introduction pipe 469.
And introduced. At this time, H₂Gas flow rate is 50scm, S
iH_Four/ H₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow
The amount is 10 sccm, CH_FourGas flow rate is 0.3sccm
Mass flow controllers 476, 477,
The pressure in the deposition chamber 419 adjusted by 478 and 479.
Force of 1.8 Torr, not shown Conductor
The opening of the sub valve was adjusted. The power of the RF power source 423
0.07W / cm³Set to, plasma forming cup 4
RF power is introduced to 21 to cause glow discharge and p /
The formation of the RF p-type layer was started on the i buffer layer, and the layer thickness 1
Turn off the RF power when the 0 nm RF p-type layer is formed
Then, the glow discharge is stopped and the formation of the RF p-type layer 105 is completed.
It was Valves 472, 482, 473, 483, 474,
484 is closed and Si into the p-type layer deposition chamber 419 is closed.
H_Four/ H₂Gas, B₂H₆/ H ₂Gas, CH_FourThe inflow of gas
Stop for 3 minutes, and H into the p-type layer deposition chamber 419 ₂Moth
After continuing to flow the gas, open the valves 471, 481 and 470.
Close H₂Of the p-type layer deposition chamber 419
1 × 10 inside and inside gas pipe^-FiveVacuum exhaust to Torr
did.

Next, the gate valve 409 is opened into the unload chamber 405 which has been evacuated by a vacuum exhaust pump (not shown) in advance, the substrate 490 is transported, and the leak valve (not shown) is opened to open the unload chamber 40.
Leaked 5.

Next, on the RF p-type layer 105, as the transparent conductive layer 112, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum deposition method.

Next, a mask having comb-shaped holes is placed on the transparent conductive layer 112, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped collector electrode 113
Was vacuum deposited by the vacuum deposition method.

Thus, the production of the solar cell is completed. This solar cell will be referred to as (SC Ex. 1), and the conditions of the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention, the RF n-type layer, and the RF
The formation conditions of the n / i buffer layer, the MWi type layer, the RFp / i buffer layer, and the RFp type layer are shown in Tables 1 (1) and 1 (2).
Shown in.

Comparative Example 1 A solar cell (SC ratio 1) was produced under the same conditions as in Example 1 except that the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was not performed.

Ten solar cells (SC Ex 1) and (SC ratio 1) each were prepared, and the initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and bias voltage application were applied. Vibration deterioration and light deterioration were measured in a high temperature and high humidity environment.

The initial photoelectric conversion efficiency can be obtained by placing the manufactured solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristic. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency of (SC ratio 1) with respect to (SC ex. 1) and the characteristic unevenness (the smaller the characteristic unevenness is, the better) are as follows.

[0126] For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was installed in a dark place with a humidity of 50% and a temperature of 25 ° C.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
It was determined by the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration deterioration test / initial photoelectric conversion efficiency).

Photodegradation was measured by placing a solar cell whose initial photoelectric conversion efficiency had been measured in advance in an environment of humidity 50% and temperature 25 ° C., and AM1.5 (100 mW / cm ² ) light for 500 hours. AM1.5 (100 mW / cm ² ) after irradiation
The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after photodegradation test / initial photoelectric conversion efficiency) was used. As a result of the measurement, the rate of decrease in photoelectric conversion efficiency after photodegradation and the rate of decrease in photoelectric conversion efficiency after vibration degradation of (SC ratio 1) with respect to (SC ex. 1) were as follows.

[0128] Vibration deterioration and light deterioration in a high temperature and high humidity environment when a bias was applied were measured. Two solar cells whose initial photoelectric conversion efficiencies were measured in advance were placed in a dark place at a humidity of 90% and a temperature of 80 ° C., and 0.7 V was applied as a forward bias voltage. The above vibration was applied to one solar cell to measure vibration deterioration, and AM1.5 was applied to the other solar cell.
Was irradiated to measure the photodegradation. As a result of the measurement,
With respect to (SC Ex 1), the rate of decrease in photoelectric conversion efficiency after vibration deterioration of (SC ratio 1) and the rate of decrease in photoelectric conversion efficiency after light deterioration were as follows.

[0129] The state of delamination was observed using an optical microscope. Delamination was not observed in (SC Ex 1), but slight delamination was observed in (SC ratio 1).

As described above, the solar cell of the present invention (SC Ex 1) has a curvilinear factor in the photoelectric conversion efficiency of the solar cell, unevenness of characteristics, photodegradation characteristics, and adhesion, which are higher than those of conventional solar cells (SC ratio 1). It was found that it has more excellent durability characteristics.

Example 2 The tandem solar cell shown in FIG. 2 was produced using the deposition apparatus shown in FIG.

Kisaka 4 having a reflection layer 201 and a reflection increasing layer 202 formed by the same method as in Example 1
90 is a rail 4 for transferring the substrate in the load chamber 401
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, the gate valve 406 was opened to carry the wafer into the transfer chamber 402 and the deposition chamber 417 which had been evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 410 and heated, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) to a pressure of about 1 × 10 ⁻⁵ Torr.

After the preparation for film formation was completed as described above, the RFn-type layer 203 made of μc-Si was formed.

An RFn type layer made of μc-Si is formed.
To H₂Gas introduction pipe for introducing gas into the deposition chamber 417
Introduced through 429, H₂Gas flow rate is 200 sccm
Valve 441, 431, 430 so that
It was adjusted with the sflow controller 436. Heap Chang
The pressure inside the bar 417 is not set to 1.2 Torr.
It was adjusted with the conductance valve shown. Substrate 490 temperature
The heater 410 for heating the slope is adjusted so that the temperature becomes 380 ° C.
After setting, when the substrate temperature is stable, SiH _Fourgas,
PH₃/ H₂Valve 44 for gas in deposition chamber 417
Operate 3, 433, 444, 434 to operate the gas introduction pipe 42
Introduced through 9. At this time, SiH_FourGas flow rate is 2s
ccm, H₂Gas flow rate is 100 sccm, PH₃/ H₂Moth
Mass flow control so that the flow rate is 200 sccm
Adjust with rollers 438, 436, 439 and
Adjust the pressure inside bar 417 to 1.2 Torr
did. The power of the RF power source 422 is 0.05 W / cm³Set up
RF power to the plasma forming cup 420
Then, a glow discharge is generated to form an RFn type layer on the substrate.
And a RFn type layer having a layer thickness of 20 nm was formed.
Turn off the RF power to stop glow discharge, and turn on the RFn type layer 2
The formation of 03 is completed. Si into the deposition chamber 417
H_FourGas, PH₃/ H₂Stop the flow of water for 4 minutes in the deposition chamber
To H₂After continuing to flow the gas, H₂Also stopped the inflow of
1 × 10 inside and inside gas pipe^-FiveVacuum exhaust to Torr
did.

Next, the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed (Table 2 (1)). In order to carry out the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention, Si ₂ H ₆ / H ₂ (dilution: 10
(00 ppm) gas, H ₂ gas, deposition chamber 417
It is introduced through a gas introduction pipe 429 into the inside of the chamber, and valves 441, 431 and 4 are provided so that the H ₂ gas flow rate becomes 700 sccm.
30 was opened, and it adjusted with the mass flow controller 436. The amount of Si ₂ H ₆ gas in the siliconcon atom containing gas is the total H
₂ Valve 44 so that 0.02% of gas flow rate
4, 434 were opened and adjusted with the mass flow controller 439. The pressure in the deposition chamber 417 is 0.010T
The conductance valve (not shown) was used to adjust the value to orr. The substrate heating heater 410 is set so that the temperature of the substrate 490 becomes 285 ° C., and when the substrate temperature is stable, the power of the VHF power source 422 is set to 0.08 W / сm ³ , the VHF power is introduced, and plasma is supplied. Forming cup 4
Glow discharge was caused to occur in 20 and the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed for 4 minutes. Then VH
F power off, stop glow discharge, deposit chamber 4
Si ₂ H ₆ / H _{2 in} 17 (dilution: 1000 ppm)
After stopping the inflow of gas, the H ₂ gas was continuously flowed into the deposition chamber 417 for 4 minutes, and then the inflow of H ₂ gas was stopped, and the inside of the deposition chamber 417 and the gas pipe were 1 × 10 ⁻⁵ To.
It was evacuated to rr.

Next, the n / i buffer layer 251 made of a-Si, the MWi type layer 204 made of a-SiGe, a-
The p / i buffer layer 261 made of Si is sequentially applied to the RFPC.
It was formed by the VD method, the MWPCVD method, and the RFPCVD method.

First, the transfer chamber 403 and i which have been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valve 407 was opened into the mold layer deposition chamber 418, and the substrate 490 was transported. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 411 and heated, and the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

To manufacture the n / i buffer layer 251, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 360 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, 463 are formed. , 453 are gradually opened to introduce Si ₂ H ₆ gas and H ₂ gas into the gas introduction pipe 4
It was made to flow into the i-type layer deposition chamber 418 through 49. At this time, the mass flow controllers 459 and 458 were adjusted so that the Si ₂ H ₆ gas flow rate was 4 sccm and the H ₂ gas flow rate was 100 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 0.8 Torr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 is set to 0.08 W / cm ³ , a bias rod 428 is applied, glow discharge is generated, and a shutter 427 is opened to start production of an n / i buffer layer on the RF n-type layer. Then, when the n / i buffer layer having a layer thickness of 10 nm was produced, the RF glow discharge was stopped and the RF
The output of the power supply 424 was turned off, and the production of the n / i buffer layer 251 was completed. The valves 464 and 454 are closed to stop the flow of Si ₂ H ₆ gas into the i-type layer deposition chamber 418, and the H ₂ gas is continuously flowed into the i-type layer deposition chamber 418 for 2 minutes, and then the valves 453 and 450. Closed, and the inside of the i-type layer deposition chamber 418 and the gas pipe was set at 1 × 10 ^−5.
Evacuated to Torr.

To prepare the MWi type layer, the substrate heating heater 411 is controlled so that the temperature of the substrate 490 becomes 380 ° C.
The valve 46 when the substrate is sufficiently heated.
1, 451, 450, 462, 452, 463, 453
Is gradually opened, and SiH ₄ gas, GeH ₄ gas, and H ₂ gas are introduced into the i-type layer deposition chamber 41 through the gas introduction pipe 449.
It was poured into 8.

At this time, the SiH ₄ gas flow rate was 45 scc
m, GeH ₄ gas flow rate is 35 sccm, H ₂ gas flow rate is 1
The mass flow controllers 456, 457, and 458 were adjusted to 30 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 5 mTorr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 was set to 0.6 W / cm ³ and applied to the bias rod 428. After that, the power of the MW power source (not shown) is set to 0.25 W / cm ³ , and the MW power is introduced into the i-type layer deposition chamber 418 through the waveguide 426 and the microwave introduction window 425 to cause glow discharge. ,
The shutter 427 is opened to start the production of the MWi-type layer on the n / i buffer layer, and when the i-type layer having a layer thickness of 0.15 μm is produced, the MW glow discharge is stopped, the output of the bias power supply 424 is turned off, and the MWi The fabrication of the mold layer 204 is completed. The valves 451 and 452 are closed to stop the inflow of SiH ₄ gas and GeH ₄ gas into the i-type layer deposition chamber 418, and H ₂ gas is continuously flowed into the i-type layer deposition chamber 418 for 2 minutes, and then the valve is closed. 453 and 450 are closed, i
1 × 1 inside the mold layer deposition chamber 418 and inside the gas pipe
It was evacuated to 0 ^-5 Torr.

To prepare the p / i buffer layer 261, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 250 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, 463. , 453 are gradually opened to introduce Si ₂ H ₆ gas and H ₂ gas into the gas introduction pipe 4
It was made to flow into the i-type layer deposition chamber 418 through 49. At this time, the mass flow controllers 459 and 458 were adjusted so that the Si ₂ H ₆ gas flow rate was ₂ sccm and the H ₂ gas flow rate was 80 sccm. The pressure inside the i-type layer deposition chamber 418 was adjusted to 0.7 Torr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 424 is set to 0.07 W / cm ³ , a bias rod 428 is applied to cause glow discharge, and a shutter 427 is opened to produce a p / i buffer layer 261 on the MWi type layer. Start, p / i with layer thickness 20 nm
When the buffer layer was produced, the RF glow discharge was stopped, the output of the RF power source 424 was cut off, and the production of the p / i buffer layer 261 was completed. By closing the valves 464 and 454, the flow of Si ₂ H ₆ gas into the i-type layer deposition chamber 418 is stopped, and H _{2 is} introduced into the i-type layer deposition chamber 418 for 2 minutes.
After continuing to flow ₂ gases, the valves 453 and 450 were closed, and the inside of the i-type layer deposition chamber 418 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Next, the RF p-type layer 205 made of a-SiC
In order to form the substrate, the gate valve 408 is opened into the transfer chamber 404 and the p-type layer deposition chamber 419 which have been evacuated by a vacuum exhaust pump (not shown) in advance, and the substrate 490 is transferred. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 412 and heated, and the inside of the p-type layer deposition chamber 419 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

So that the temperature of the substrate 490 becomes 250 ° C.
Set the substrate heating heater 412 to stabilize the substrate temperature.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂
Gas, CH_FourValve 4 for depositing gas in deposition chamber 419
81, 471, 470, 482, 472, 483, 47
Operate 3, 484, 474 through the gas introduction pipe 469
Introduced. At this time, H₂Gas flow rate is 60scm, Si
H_Four/ H₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow
Is 10 sccm, CH_FourGas flow becomes 0.3 sccm
Mass flow controllers 476, 477, 47
The pressure in the deposition chamber 419 is adjusted by
Conductance bar not shown so as to be 2.0 Torr
The opening of the lube was adjusted. The power of the RF power source 423 is 0.0
7 W / cm ³To the plasma forming cup 421.
Introduce RF power to cause glow discharge and p / i back
The formation of the RF p-type layer is started on the fur layer, and the layer thickness is 10 nm.
When the RF p-type layer is formed, turn off the RF power and
The low discharge was stopped and the formation of the RF p-type layer 205 was completed. Ba
Lubes 472, 482, 473, 483, 474, 484
Closed and SiH into the p-type layer deposition chamber 419_Four/
H₂Gas, B₂H₆/ H₂Gas, CH_FourStop the flow of gas,
H into the p-type layer deposition chamber 419 for 3 minutes₂Flowing gas
And then close valves 471, 481, 470
H₂Of the p-type layer deposition chamber 419 and
1 x 10 in the gas pipe^-FiveEvacuated to Torr.

Next, in order to form an RFn-type layer made of μc-Si, H ₂ gas was introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate was 200 s.
The valves 441, 431, and 430 were opened so as to be ccm, and the mass flow controller 436 adjusted. The conductance valve (not shown) was used to adjust the pressure in the deposition chamber 417 to 1.1 Torr. Board 49
Heater 4 for heating the substrate so that the temperature of 0 becomes 250 ° C.
10 was set, and when the substrate temperature became stable, SiH ₄
The gas, PH ₃ / H ₂ gas, was introduced into the deposition chamber 417 through the gas introduction pipe 429 by operating the valves 443, 433, 444, 434. At this time, SiH ₄ gas flow rate is ₂ sccm, H ₂ gas flow rate is 50 sccm, PH ₃ / H
_{The 2} gas flow rate was adjusted to 250 sccm by the mass flow controllers 438, 436 and 439, and the pressure in the deposition chamber 417 was adjusted to 1.1 Torr. The power of the RF power source 422 is 0.04 W / cm ³
And RF power is introduced into the plasma forming cup 420 to cause glow discharge, start forming the RFn type layer on the RFp type layer, and form the RFn type layer with a layer thickness of 10 nm. Turn off, stop glow discharge, RF
The formation of the n-type layer 206 is completed. Stop the inflow of SiH ₄ gas and PH ₃ / H ₂ into the deposition chamber 417 for 2 minutes,
After continued to flow H ₂ gas into the deposition chamber, the flow of H ₂ is also stopped, the deposition chamber and the gas in the pipe 1 × 10 ^- was evacuated to ⁵ Torr.

Next, a hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed (Table 2 (2)). In order to perform the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention, SiH ₄ / H ₂ (dilution: 100
0 ppm) gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 60.
Valves 441, 431, 430 to be 0 sccm
Opened and adjusted with the mass flow controller 436.
The content of silicon atoms was adjusted with the mass flow controller 437 by opening the valves 442 and 432 so that the SiH ₄ gas content was 0.06% with respect to the total H ₂ gas flow rate. The pressure in the deposition chamber 417 was adjusted to 1.0 Torr by a conductance valve (not shown). Board 49
Heater 4 for heating the substrate so that the temperature of 0 becomes 200 ° C.
10 was set, and when the substrate temperature was stable, the power of the RF power supply 422 was set to 0.02 W / cm ³ , RF power was introduced, and glow discharge was generated in the plasma forming cup 420, and this was followed for 3 minutes. The hydrogen plasma treatment containing a small amount of silane-based gas of the invention was performed. After that, the RF power supply is turned off, the glow discharge is stopped, and the SiH ₄ /
Stop the inflow of H ₂ (dilution: 1000 ppm) gas, and 3
Minutes, after continued to flow推積chamber 417 in F H ₂ gas, stopping the inflow of the H ₂ gas, the inside of the deposition chamber 417 and gas pipe were evacuated to 1x10 ^-5 Tоrr. Next, an n / i buffer layer 25 made of a-SiC
2. The RFi type layer 207 made of a-Si and the p / i buffer layer 262 made of a-SiC were sequentially formed by the RFPCVD method.

First, the transfer chamber 403 and i which have been evacuated by a vacuum exhaust pump (not shown) in advance.
The gate valve 407 was opened into the mold layer deposition chamber 418, and the substrate 490 was transported. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 411 and heated, and the i-type layer deposition chamber 418 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

To prepare the n / i buffer layer 252, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 250 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, 463. , 453,
465 and 455 were gradually opened, and Si ₂ H ₆ gas, H ₂ gas, and CH ₄ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, Si ₂ H ₆
Gas flow rate is 0.5 sccm, H ₂ gas flow rate is 50 sccc
The mass flow controllers 459, 458, and 460 adjusted the flow rates of m and CH ₄ gas to be 0.2 sccm.

The pressure in the i-type layer deposition chamber 418 is
The opening of the conductance valve (not shown) was adjusted so as to be 1.5 Torr. Next, set the RF power source 424 to 0.0
The bias bar 428 is applied to the RF n-type layer at 6 W / cm ³ to generate glow discharge, and the shutter 427 is opened to start preparation of the n / i buffer layer on the RF n-type layer. When the buffer layer is prepared, R
Stop the F glow discharge, turn off the output of the RF power source 424, n
/ I buffer layer 252 was completed. Valve 46
4, 454, 465, 455 are closed to stop the inflow of Si ₂ H ₆ gas and CH ₄ gas into the i-type layer deposition chamber 418, and H ₂ gas is flowed into the i-type layer deposition chamber 418 for 2 minutes. After continuing, the valves 453 and 450 are closed and i
1 × 1 inside the mold layer deposition chamber 418 and inside the gas pipe
It was evacuated to 0 ^-5 Torr.

To form the RFi type layer, the substrate heating heater 411 is controlled so that the temperature of the substrate 490 becomes 200 ° C.
The valve 46 when the substrate is sufficiently heated.
Gradually open 4, 454, 450, 463, 453,
Si ₂ H ₆ gas and H ₂ gas are passed through the gas introduction pipe 449 to i
It was made to flow into the mold layer deposition chamber 418. At this time, S
i ₂ H ₆ gas flow rate is ₂ sccm, H ₂ gas flow rate is 60 sc
Each mass flow controller 45 to be cm
Adjusted at 9,458. The pressure inside the i-type layer deposition chamber 418 was adjusted to 0.6 Torr by adjusting the opening of a conductance valve (not shown). Next, the RF power source 42
4 was set to 0.07 W / cm ³ and applied to the bias rod 428 to cause glow discharge, and the shutter 427 was opened to start the preparation of the RFi type layer on the n / i buffer layer 252, and the layer thickness When the i-type layer having a thickness of 110 nm was produced, the RF glow discharge was stopped, the output of the RF power source 424 was cut off, and the production of the RF i-type layer 207 was completed. Valve 464,
454 is closed to stop the flow of Si ₂ H ₆ gas into the i-type layer deposition chamber 418, and H ₂ gas is continuously flowed into the i-type layer deposition chamber 418 for 2 minutes, and then the valve 45
3, 450 were closed, and the inside of the i-type layer deposition chamber 418 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

In order to form the p / i buffer layer 262, the substrate heating heater 411 is set so that the temperature of the substrate 490 becomes 200 ° C., and when the substrate is sufficiently heated, the valves 464, 454, 450, 463. , 453,
465 and 455 were gradually opened, and Si ₂ H ₆ gas, H ₂ gas, and CH ₄ gas were caused to flow into the i-type layer deposition chamber 418 through the gas introduction pipe 449. At this time, Si ₂ H ₆
Gas flow rate is 0.5 sccm, H ₂ gas flow rate is 50 sccc
The mass flow controllers 459, 458, and 460 were adjusted so that the flow rates of m and CH ₄ gas were 0.3 sccm. The pressure in the i-type layer deposition chamber 418 is
The opening of the conductance valve (not shown) was adjusted so as to be 1.3 Torr. Next, set the RF power source 424 to 0.0
The bias rod 428 is set to 6 W / cm ³ , glow discharge is caused to occur, and the shutter 427 is opened to start the production of the p / i buffer layer on the RFi type layer, and the p / i layer having a layer thickness of 15 nm is formed. When the buffer layer is prepared, R
Stop the F glow discharge, turn off the output of the RF power supply 424, p
The production of the / i buffer layer 262 is completed. Valve 46
4, 454, 465, 455 are closed to stop the inflow of Si ₂ H ₆ gas and CH ₄ gas into the i-type layer deposition chamber 418 and H ₂ into the i-type layer deposition chamber 418 for 2 minutes.
After continuing to flow the gas, close the valves 453 and 450,
1 × in the i-type layer deposition chamber 418 and the gas pipe
It was evacuated to 10 ^-5 Torr.

Next, the RF p-type layer 208 made of a-SiC
In order to form the substrate, the gate valve 408 is opened into the transfer chamber 404 and the p-type layer deposition chamber 419 which have been evacuated by a vacuum exhaust pump (not shown) in advance, and the substrate 490 is transferred. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 412 and heated, and the inside of the p-type layer deposition chamber 419 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

The temperature of the substrate 490 should be 170 ° C.
Set the substrate heating heater 412 to stabilize the substrate temperature.
By the way, H₂Gas, SiH_Four/ H₂Gas, B₂H₆/ H₂
Gas, CH_FourValve 4 for depositing gas in deposition chamber 419
81, 471, 470, 482, 472, 483, 47
Operate 3, 484, 474 through the gas introduction pipe 469
Introduced. At this time, H₂Gas flow rate is 60scm, Si
H_Four/ H₂Gas flow rate is 2 sccm, B₂H₆/ H₂Gas flow
Is 10 sccm, CH_FourGas flow becomes 0.3 sccm
Mass flow controllers 476, 477, 47
The pressure in the deposition chamber 419 is adjusted by
Conductance bar not shown so as to be 2.0 Torr
The opening of the lube was adjusted. The power of the RF power source 423 is 0.0
7 W / cm ³To the plasma forming cup 421.
Introduce RF power to cause glow discharge and p / i back
The formation of the RF p-type layer is started on the fur layer 262, and the layer thickness 1
Turn off the RF power when the 0 nm RF p-type layer is formed
Then, the glow discharge is stopped and the formation of the RF p-type layer 208 is completed.
It was Valves 472, 482, 473, 483, 474,
484 is closed and Si into the p-type layer deposition chamber 419 is closed.
H_Four/ H₂Gas, B₂H₆/ H₂Gas, CH_FourThe inflow of gas
Stop, 2 minutes, H into the p-type layer deposition chamber 419₂Moth
After continuing to flow the gas, open the valves 471, 481 and 470.
Close H₂Of the p-type layer deposition chamber 419
1 × 10 inside and inside gas pipe^-FiveVacuum exhaust to Torr
did.

Next, the gate valve 409 is opened into the unload chamber 405 which has been evacuated by a vacuum exhaust pump (not shown) in advance to transfer the substrate 490, and the leak valve (not shown) is opened to unload the chamber 40.
Leaked 5.

Next, on the RF p-type layer 208, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum vapor deposition method as a transparent conductive layer 212.

Next, a mask having comb-shaped holes is placed on the transparent conductive layer 212, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped collector electrode 213
Was vacuum deposited by the vacuum deposition method.

With the above, the production of the solar cell was completed. This solar cell will be referred to as (SC Ex. 2), and the conditions of the hydrogen plasma treatment containing trace silane-based gas of the present invention, the RF n-type layer, n /
i buffer layer, MWi type layer, p / i buffer layer, R
The conditions for forming the Fi type layer and the RFp type layer are shown in Tables 2 (1) to 2
It shows in (3).

Comparative Example 2 A solar cell (SC ratio 2) was produced under the same conditions as in Example 2 except that the hydrogen plasma treatment containing a small amount of silane-based gas according to the present invention was not performed.

Eight solar cells (SC Ex 2) and (SC ratio 2) were prepared, and the initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and bias voltage application were applied. Vibration deterioration and light deterioration were measured in a high temperature and high humidity environment.

The initial photoelectric conversion efficiency can be obtained by placing the manufactured solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristic. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency and the characteristic unevenness of (SC Ex 2) with respect to (SC Ratio 2) were as follows.

[0161] For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was installed in a dark place with a humidity of 50% and a temperature of 25 ° C.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
It was determined by the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration deterioration test / initial photoelectric conversion efficiency).

The photodegradation was measured by setting a solar cell whose initial photoelectric conversion efficiency had been measured in advance in an environment of a humidity of 50% and a temperature of 25 ° C. and applying AM-1.5 (100 mW / cm ² ) light. AM1.5 (100 mW / cm after irradiation for 500 hours
² ) The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after photodegradation test / initial photoelectric conversion efficiency) was used. As a result of the measurement, the reduction rate of the photoelectric conversion efficiency after the photodegradation and the reduction rate of the photoelectric conversion efficiency after the vibration degradation of (SC ratio 2) with respect to (SC ex. 2) are as follows.

[0163] We measured vibration deterioration and light deterioration under high temperature and high humidity environment with bias applied. Two solar cells whose initial photoelectric conversion efficiencies were measured in advance were placed in a dark place at a humidity of 90% and a temperature of 80 ° C., and 0.7 V was applied as a forward bias voltage. The above vibration was applied to one solar cell to measure the vibration deterioration, and the other solar cell was irradiated with light of AM1.5 to measure the light deterioration. As a result of measurement, (S
In comparison with C Ex 2), the reduction rate of the photoelectric conversion efficiency after the vibration deterioration of (SC ratio 2) and the reduction rate of the photoelectric conversion efficiency after the light deterioration were as follows.

[0164] The state of delamination was observed using an optical microscope. Delamination was not observed in (SC Ex. 2), but slight delamination was observed in (SC ratio 2).

As described above, the solar cell of the present invention (SC Ex 2) has a curvilinear factor in the photoelectric conversion efficiency of the solar cell, unevenness of characteristics, photodegradation characteristics, adhesion, and the like, compared with the conventional solar cell (SC ratio 2). It was found that it has more excellent durability characteristics.

(Example 3) The triple type solar cell of FIG. 3 was produced using the deposition apparatus shown in FIG. A reflective layer 301 and a reflective enhancement layer 30 prepared by the same method as in Example 1.
The base chamber 490 where the 2 is formed is the load chamber 40
1 was placed on the substrate transfer rail 413, and the inside of the load chamber 401 was evacuated to a pressure of about 1 × 10 ⁻⁵ Torr by a vacuum exhaust pump (not shown).

Next, the gate valve 406 was opened to carry the wafer into the transfer chamber 402 and the deposition chamber 417 which had been evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 410 and heated, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) to a pressure of about 1 × 10 ⁻⁵ Torr.

After the preparation for film formation is completed as described above, R consisting of μc-Si is prepared by the same method as in Example 2.
The Fn type layer 303 was formed.

Next, the gate valve 406 was opened to carry into the transfer chamber 403 and the deposition chamber 418, which had been evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 411 and heated, and the inside of the deposition chamber 418 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, a hydrogen plasma treatment containing a small amount of silane-based gas according to the present invention was performed (Table 3 (1)). In order to carry out the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention, SiCl ₂ H ₂ / He (dilution:
1000 ppm) gas and H ₂ gas are deposited in the deposition chamber 41.
8 through a gas introducing pipe 449, and valves 463, 453, 4 so that the H ₂ gas flow rate may be 400 sccm.
50 was opened and adjusted with the mass flow controller 458. The silicon atom-containing gas has a valve 4 so that the amount of SiCl ₂ H ₂ gas is 0.08% with respect to the total H ₂ gas flow rate.
65 and 455 were opened and adjusted with the mass flow controller 460. The pressure in the deposition chamber 418 is 0.010
The conductance valve (not shown) was used to adjust the torque to Torr. The substrate heating heater 411 was set so that the temperature of the substrate 490 became 350 ° C., and when the substrate temperature became stable, the power of the MW power source (not shown) was set to 0.1 W / cm ^3.
To the waveguide 426 and the microwave introduction window 425.
The MW power was introduced into the i-type layer deposition chamber 418 through to generate a glow discharge, and the shutter 427 was opened to perform the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention for 4 minutes. After that, the MW power supply is turned off to stop the glow discharge, and SiCl ₂ H ₂ /
Stop the flow of He (dilution: 1000ppm) gas, 4
After continuously flowing H ₂ gas into the deposition chamber 418 for a minute, the inflow of H ₂ gas was stopped and the inside of the deposition chamber 418 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Then, a-Si is formed by the same method as in the second embodiment.
N / i buffer layer 351 made of a, MWi type layer 304 made of a-SiGe, p / i buffer layer 361 made of a-Si, RF p type layer 305 made of a-SiC,
The RFn-type layer 306 made of μc-Si was sequentially formed.

Next, a hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed (Table 3 (2)). In order to perform the hydrogen plasma treatment containing a small amount of silane-based gas according to the present invention, SiH ₄ / H ₂ (dilution: 1
(000 ppm) gas and H ₂ gas are deposited in the deposition chamber 41.
7 through a gas introducing pipe 429, and valves 441, 431, so that the H ₂ gas flow rate becomes 500 sccm.
430 was opened and adjusted with the mass flow controller 436. The silicon atom-containing gas has a SiH ₄ gas amount of H ₂
Balkh 44 to be 0.07% to the gas flow rate
2, 432 were opened and adjusted with the mass flow controller 437. The pressure in the deposition chamber 417 is 1.1 To
The conductance valve (not shown) was used to adjust to rr. The substrate heating heater 410 was set so that the temperature of the substrate 490 was 300 ° C., and when the substrate temperature became stable, the power of the RF power source 422 was set to 0.04 W / cm ³ and the RF power was introduced to generate plasma. Forming cup 420
A glow discharge was caused to occur inside, and a minute amount of silane-based gas-containing hydrogen plasma treatment of the present invention was performed. After that, the RF power supply was turned off, the glow discharge was stopped, the inflow of SiH ₄ / H ₂ (dilution degree: 1000 ppm) gas into the deposition chamber 417 was stopped, and H ₂ gas was continued to flow into the deposition chamber 417 for 3 minutes. After that, the inflow of H ₂ gas was stopped, and the inside of the deposition chamber 417 and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Then, a-Si is formed by the same method as in the second embodiment.
An n / i buffer layer 352 made of a, an MWi type layer 307 made of a-SiGe, ap / i buffer layer 362 made of a-Si, an RF p type layer 308 made of a-SiC,
The RFn-type layer 309 made of μc-Si was sequentially formed.

Next, a trace amount of silane-based gas-containing hydrogen purifier of the present invention is
Plasma treatment was performed (Table 3 (3)). Minor chive of the present invention
To perform the hydrogen plasma containing hydrogen gas,
SiH as gas containing atoms_Four/ H₂(Dilution: 10
00ppm) gas, H₂Gas in deposition chamber 417
Gas through the gas inlet pipe 429,₂Gas flow rate is 7
Valves 441, 431, 43 to be 00 sccm
Open 0 and adjust with the mass flow controller 436
It was Silicon atom-containing gas is SiH_FourGas amount is all H₂Moth
Valve 442, so that the flow rate becomes 0.04%,
432, open and adjust with mass flow controller 437
did. The pressure inside the deposition chamber 417 is 1.0 Torr
Adjust the conductance valve (not shown) so that
It was Heat the substrate so that the temperature of the substrate 490 becomes 230 ° C.
Where the heater 410 is set and the substrate temperature is stable
Then, the power of the RF power source 422 is 0.03 W / cm.³Set to
Then, RF power is introduced, and inside the plasma forming cup 420.
Glow discharge is caused to occur for 2 minutes, and a minute amount of the silane system of the present invention
A gas-containing hydrogen plasma treatment was performed. Then turn on the RF power
Turn off the glow discharge to stop the inside of the deposition chamber 417.
SiH_Four/ H₂(Dilution: 1000ppm) Inflow of gas
Stop for 3 minutes into the deposition chamber 417 ₂Gas
After continuing to flow, H₂Gas flow is stopped and deposition chamber
ー 1 × 10 inside 417 and gas pipe^-FiveTo Torr
Evacuated.

Then, a-Si is formed by the same method as in the second embodiment.
An n / i buffer layer 353 made of C, an RF i type layer 310 made of a-Si, a p / i buffer layer 363 made of a-SiC, and an RF p type layer 311 made of a-SiC were sequentially formed by the RFPCVD method.

Next, on the RF p-type layer 311, as a transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum deposition method.

Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped collector electrode 313
Was vacuum deposited by the vacuum deposition method.

With the above, the production of the solar cell was completed. This solar cell will be referred to as (SC Ex. 3), and will be described with reference to the hydrogen plasma treatment conditions containing a trace amount of silane-based gas, the RF n-type layer, and n /
i buffer layer, MWi type layer, p / i buffer layer, R
The conditions for forming the Fi type layer and the RFp type layer are shown in Tables 3 (1) to 3
It shows in (4).

Comparative Example 3 A solar cell (SC ratio 3) was produced under the same conditions as in Example 3 except that the hydrogen plasma treatment containing a small amount of silane-based gas according to the present invention was not performed.

Eight solar cells (SC Ex 3) and (SC ratio 3) were prepared, and initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and high temperature when bias voltage was applied. Vibration deterioration and light deterioration were measured in a high humidity environment.

The initial photoelectric conversion efficiency can be obtained by placing the manufactured solar cell under AM1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristic. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency and the characteristic unevenness of (SC Ex 3) with respect to (SC Ratio 3) were as follows.

[0182] For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was installed in a dark place with a humidity of 50% and a temperature of 25 ° C.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
It was determined by the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration deterioration test / initial photoelectric conversion efficiency).

The photodegradation was measured by setting a solar cell whose initial photoelectric conversion efficiency had been measured in advance in an environment of a humidity of 50% and a temperature of 25 ° C. and applying AM1.5 (100 mW / cm ² ) light for 500 hours. AM1.5 (100 mW / cm ² ) after irradiation
The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after photodegradation test / initial photoelectric conversion efficiency) was used. As a result of the measurement, the rate of decrease in photoelectric conversion efficiency after photodegradation and the rate of decrease in photoelectric conversion efficiency after vibration degradation of (SC ratio 3) to (SC ex 3) were as follows.

[0184] Vibration deterioration and light deterioration in a high temperature and high humidity environment when a bias was applied were measured. Two solar cells whose initial photoelectric conversion efficiency was measured in advance were placed in a dark place with a humidity of 90% and a temperature of 80 ° C., and 0.7 V was applied as a forward bias voltage. The above vibration was applied to one solar cell to measure the vibration deterioration, and the other solar cell was irradiated with light of AM1.5 to measure the light deterioration.

As a result of the measurement, for (SC Ex 3), (S
The decrease rate of the photoelectric conversion efficiency after the vibration deterioration of C ratio 3) and the decrease rate of the photoelectric conversion efficiency after the light deterioration were as follows.

[0186] The state of delamination was observed using an optical microscope. Delamination was not observed in (SC Ex 3), but slight delamination was observed in (SC ratio 3).

[0187] As described above, the solar cell of the present invention (SC Ex 3) has a curvilinear factor in photoelectric conversion efficiency of the solar cell, unevenness of characteristics, photodegradation characteristics, adhesion, which are higher than those of conventional solar cells (SC ratio 3). It was found that it has more excellent durability characteristics.

(Example 4) As in Example 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed three times under the conditions of Table 4 (1), and Example 3 was used. A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 4 (1) shows the treatment conditions for hydrogen plasma containing a small amount of silane-based gas.
Table 4 (2) shows the manufacturing conditions of the triple solar cell.

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 4 (3).

The hydrogen flow rate of the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention is a suitable flow rate of 1 to 2000 sccm in terms of the fill factor in the photoelectric conversion efficiency of the solar cell, characteristic unevenness, photodegradation characteristics, adhesion and durability. I knew it was.

(Embodiment 5) As in Embodiment 3, using the deposition apparatus shown in FIG. 4, the trace amount silane-based gas-containing hydrogen plasma treatment of the present invention was performed three times under the conditions of Table 5 (1), and Embodiment 3 A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 5 (1) shows the treatment conditions for hydrogen plasma containing a small amount of silane-based gas.
Table 5 (2) shows the manufacturing conditions of the triple solar cell.

In the same manner as in Example 3, the produced triple type solar cell was subjected to the table evaluation. The results are shown in Table 5 (3).

Even if the input power of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was changed from the RF power supply of Example 4 to the VHF power supply, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the photodegradation characteristic, and the adhesion were observed. It was found that a hydrogen flow rate of 1 to 2000 sccm is a suitable flow rate in terms of durability and durability.

Example 6 As in Example 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed three times under the conditions of Table 6 (1), and Example 3 was used. A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 6 (1) shows the treatment conditions for hydrogen plasma containing a small amount of silane-based gas.
Table 6 (2) shows the manufacturing conditions of the triple solar cell.

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 6 (3).

The addition amount of the silane-based gas-containing gas added to the hydrogen gas in the hydrogen plasma treatment of the trace amount silane-based gas of the present invention is a fill factor in the photoelectric conversion efficiency of the solar cell,
In terms of characteristic unevenness, photodegradation characteristics, adhesiveness, and durability, 0.
It was found that the preferable range is 001% to 0.1%.

(Embodiment 7) As in Embodiment 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed three times under the conditions of Table 7 (1), and Embodiment 3 A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 7 (1) shows the treatment conditions for hydrogen plasma containing silane-based gas.
Table 7 (2) shows the manufacturing conditions of the solar ripple type solar cell.

The triple solar cell thus prepared was evaluated in the same manner as in Example 3. The results are shown in Table 7 (3).

The addition amount of the silane-based gas-containing gas added to the hydrogen gas in the hydrogen plasma treatment for the trace silane-based gas-containing hydrogen plasma of the present invention is the same as that of the solar battery even if the input power is changed from the RF power supply of Example 6 to the VHF power supply. It was found that 0.001% to 0.1% is the preferable range in the fill factor, the characteristic unevenness, the photodegradation property, the adhesiveness, and the durability in the photoelectric conversion efficiency.

(Embodiment 8) As in Embodiment 3, using the deposition apparatus shown in FIG. 4, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed three times under the conditions of Table 8 (1), and Embodiment 3 A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 8 (1) shows the treatment conditions for hydrogen plasma containing a small amount of silane-based gas.
Table 8 (2) shows the manufacturing conditions of the triple solar cell.

The triple solar cell thus prepared was evaluated in the same manner as in Example 3. The results are shown in Table 8 (3).

The addition amount of the silane-based gas-containing gas added to the hydrogen gas for the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention is the same as that of the solar battery even if the input power is changed from the RF power supply of Example 6 to the MW power supply. It was found that 0.001% to 0.1% is the preferable range in the fill factor, the characteristic unevenness, the photodegradation property, the adhesiveness, and the durability in the photoelectric conversion efficiency.

(Embodiment 9) As in Embodiment 3, using the deposition apparatus shown in FIG. 4, the trace amount silane-based gas-containing hydrogen plasma treatment of the present invention was performed three times under the conditions of Table 9 (1), and Embodiment 3 A triple type solar cell of FIG. 3 was produced in the same manner as in. Table 9 (1) shows the treatment conditions for hydrogen plasma containing a small amount of silane-based gas.
Table 9 (2) shows the manufacturing conditions of the triple solar cell.

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 9 (3).

The pressure of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is as follows:
Fill factor in photovoltaic conversion efficiency of solar cells, characteristic unevenness,
0.05 Torr in light deterioration characteristics, adhesion and durability
Therefore, it was found that 10 Torr is a preferable range.

(Example 10) As in Example 3, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was carried out three times under the conditions of Table 10 (1) using the deposition apparatus shown in FIG.
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
0 (1) shows the manufacturing conditions of the triple type solar cell in Table 10.
It shows in (2).

The produced ripple-type solar cell was evaluated in the same manner as in Example 3. The results are shown in Table 10 (3).

The pressure of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is such that when a VHF power source is used as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the photodegradation characteristic, the adhesion, and the durability. At 0.0001
It has been found that a preferable range is from Torr to 1 Torr.

(Example 11) Similar to Example 3, hydrogen plasma treatment containing trace silane-based gas of the present invention was carried out three times under the conditions of Table 11 (1) using the deposition apparatus shown in FIG.
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
Table 1 shows the manufacturing conditions for triple solar cells in 1 (1).
It shows in (2).

The produced triple solar cell was evaluated in the same manner as in Example 3. The results are shown in Table 11 (3).

The pressure of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is as follows:
Fill factor in photovoltaic conversion efficiency of solar cells, characteristic unevenness,
0.0001To in light deterioration characteristics, adhesion and durability
It has been found that a preferable range is rr to 0.01 Torr.

(Example 12) [0212] As in Example 3, the trace amount silane-based gas-containing hydrogen plasma treatment of the present invention was performed three times under the conditions of Table 12 (1) using the deposition apparatus shown in Fig. 4.
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
Table 2 shows the production conditions for triple solar cells in 2 (1).
It shows in (2).

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 12 (3).

The input power density (electric energy) of the hydrogen plasma treatment containing a small amount of silane-based gas according to the present invention is RF input power.
When using the power supply, found fill factor of the photoelectric conversion efficiency of the solar cell, the characteristics irregularity, photodegradation characteristics, adhesiveness, it is preferable range 1.0 W / cm ³ from 0.01 W / cm ³ in durability It was

(Example 13) Similar to Example 3, hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed three times under the conditions of Table 13 (1) using the deposition apparatus shown in FIG.
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
3 (1) shows the manufacturing conditions of the triple type solar cell in Table 16.
It shows in (2).

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 13 (3).

The input power density (electric energy) of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is VH to the input power.
When using F power, fill factor of the photoelectric conversion efficiency of the solar cell, the characteristics irregularity, photodegradation characteristics, adhesiveness, it is preferable range 1.0 W / cm ³ from 0.01 W / cm ³ in durability Do you get it.

(Example 14) [0218] As in Example 3, using the deposition apparatus shown in Fig. 4, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was carried out three times under the conditions shown in Table 14 (1).
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
Table 4 (1) shows the production conditions for triple solar cells.
It shows in (2).

The produced triple solar cell was evaluated in the same manner as in Example 3. The results are shown in Table 14 (3).

The input power density (power amount) of the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention is MW in the input power.
It was found that when a power source is used, 0.1 W / cm ³ to 10 W / cm ³ are preferable ranges in the fill factor, the characteristic unevenness, the photodegradation characteristic, the adhesion, and the durability in the photoelectric conversion efficiency of the solar cell.

(Example 15) As in Example 3, using the deposition apparatus shown in FIG. 4, the trace amount silane-based gas-containing hydrogen plasma treatment of the present invention was performed three times under the conditions of Table 15 (1).
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
Table 5 (1) shows the manufacturing conditions for triple solar cells.
It shows in (2).

The triple type solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 15 (3).

The substrate temperature of the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is such that when an RF power source is used for the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the photodegradation characteristic, the adhesion, and the durability. It was found that 100 ° C. to 400 ° C. is a preferable range in terms of sex.

(Example 16) Similar to Example 3, using the deposition apparatus shown in FIG. 4, the trace amount silane gas-containing hydrogen plasma treatment of the present invention was performed three times under the conditions of Table 16 (1),
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
Table 6 (1) shows the manufacturing conditions for triple solar cells.
It shows in (2).

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 16 (3).

The substrate temperature in the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention is such that when a VHF power source is used as the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the photodegradation characteristic, the adhesion, and the durability. It was found that 50 ° C. to 300 ° C. is a preferable range in terms of sex.

(Example 17) [0227] As in Example 3, using the deposition apparatus shown in Fig. 4, hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was carried out three times under the conditions of Table 17 (1).
The triple type solar cell of FIG. 3 was produced in the same manner as in Example 3. Table 1 shows the hydrogen plasma treatment conditions containing a trace amount of silane-based gas.
7 (1) shows the manufacturing conditions of the triple type solar cell in Table 17.
It shows in (2).

The triple solar cell thus produced was evaluated in the same manner as in Example 3. The results are shown in Table 17 (3).

The substrate temperature of the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention is such that when an MW power source is used for the input power, the fill factor in the photoelectric conversion efficiency of the solar cell, the characteristic unevenness, the photodegradation characteristic, and the series resistance. 5 in characteristics and durability
It has been found that 0 ° C to 300 ° C is the preferred range.

Example 18 The triple type solar cell of FIG. 3 was produced using the deposition apparatus shown in FIG.

Substrate 4 on which the reflection layer 301 and the reflection increasing layer 302 are formed, which is prepared by the same method as in Example 1.
90 is a rail 4 for transferring the substrate in the load chamber 401
13 and the inside of the load chamber 401 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Next, the gate valve 406 was opened to carry the wafer into the transfer chamber 402 and the deposition chamber 417 which had been evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 410 and heated, and the inside of the deposition chamber 417 was evacuated by a vacuum exhaust pump (not shown) to a pressure of about 1 × 10 ⁻⁵ Torr.

Next, a hydrogen plasma treatment containing a small amount of silane-based gas was performed under the conditions shown in Table 18 (1). SiH ₄ / H ₂ (dilution: 1000 ppm) as a silicon atom-containing gas is used for hydrogen plasma treatment containing a small amount of silane-based gas.
Gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 800 sccm.
The valves 441, 431, and 430 were opened so as to be set, and the mass flow controller 436 adjusted. As for the silicon atom-containing gas, SiH ₄ is 0.0 with respect to the total H ₂ gas flow rate.
The valves 442 and 432 were opened and adjusted with the mass flow controller 437 so as to be 5%. Deposition chamber 4
The pressure inside 17 was adjusted with a conductance valve (not shown) so as to be 1.0 Torr. The temperature of the substrate 490 is 3
The substrate heating heater 410 was set to 60 ° C., and when the substrate temperature became stable, the power of the RF power source 422 was set to 0.03 W / cm ³ , and the RF power was introduced.
Glow discharge was generated in the plasma-forming cup 420, and a minute amount of silane-based gas-containing hydrogen plasma treatment was performed for 3 minutes. After that, the RF power supply is turned off to stop the glow discharge, and the SiH ₄ / H ₂ (dilution degree: 10) into the deposition chamber 417 is stopped.
(00 ppm) gas is stopped, and H ₂ gas is continuously flowed into the deposition chamber 417 for 5 minutes, then H ₂ gas is also stopped and the inside of the deposition chamber 417 and the gas pipe is reduced to 1 × 10 ⁻⁵ Torr. Evacuated.

After the preparation for film formation is completed as described above, R consisting of μc-Si is prepared by the same method as in Example 2.
The Fn type layer 303 was formed.

Next, a hydrogen plasma treatment containing a small amount of silane-based gas was performed under the conditions shown in Table 18 (2). SiH ₄ / H ₂ (dilution: 1000 ppm) as a silicon atom-containing gas is used for hydrogen plasma treatment containing a small amount of silane-based gas.
Gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 700 sccm.
The valves 441, 431, and 430 were opened so as to be set, and the mass flow controller 436 adjusted. As for the silicon atom-containing gas, SiH ₄ is 0.0 with respect to the total H ₂ gas flow rate.
The valves 442 and 432 were opened and adjusted with the mass flow controller 437 so as to be 4%. The conductance valve (not shown) was used to adjust the pressure in the deposition chamber 417 to 0.9 Torr. The substrate heating heater 410 was set so that the temperature of the substrate 490 was 350 ° C., and when the substrate temperature became stable, the power of the RF power source 422 was set to 0.03 W / cm ³ and RF power was introduced.
Glow discharge was generated in the plasma-forming cup 420, and a minute amount of silane-based gas-containing hydrogen plasma treatment was performed for 3 minutes. After that, the RF power supply is turned off to stop the glow discharge, and the SiH ₄ / H ₂ (dilution degree: 10) into the deposition chamber 417 is stopped.
(00 ppm) gas is stopped, and H ₂ gas is continuously flowed into the deposition chamber 417 for 5 minutes, then H ₂ gas is also stopped and the inside of the deposition chamber 417 and the gas pipe is reduced to 1 × 10 ⁻⁵ Torr. Evacuated.

Next, the gate valve 407 was opened to carry into the transfer chamber 403 and the deposition chamber 418, which had been evacuated by a vacuum exhaust pump (not shown) in advance. The back surface of the substrate 490 was brought into close contact with the substrate heating heater 411 and heated, and the inside of the deposition chamber 418 was evacuated by a vacuum exhaust pump (not shown) until the pressure became about 1 × 10 ⁻⁵ Torr.

Then, a-Si is formed by the same method as in the second embodiment.
N / i buffer layer 351 made of a, MWi type layer 304 made of a-SiGe, p / i buffer layer 361 made of a-Si, RF p type layer 305 made of a-SiC,
The RFn-type layer 306 made of μc-Si was sequentially formed.

Next, the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was performed (Table 18 (3)). To carry out the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention, SiH ₄ / H ₂ (dilution: 10
00 ppm) gas and H ₂ gas are introduced into the deposition chamber 417 through the gas introduction pipe 429, and the H ₂ gas flow rate is 6
Valves 441, 431, 43 to be 00 sccm
0 was opened and adjusted with the mass flow controller 436. The silicon atom-containing gas is controlled by the valve 442 so that the amount of SiH ₄ gas becomes 0.04% with respect to the total H ₂ gas flow rate.
432 was opened and adjusted with the mass flow controller 437. The conductance valve (not shown) was used to adjust the pressure in the deposition chamber 417 to 0.9 Torr.
When the substrate heating heater 410 is set so that the temperature of the substrate 490 becomes 300 ° C. and the substrate temperature becomes stable,
Set the power of the RF power source 422 to 0.03 W / cm ³ ,
RF power was introduced to cause glow discharge in the plasma forming cup 420, and the trace amount silane-based gas-containing hydrogen plasma treatment of the present invention was performed for 3 minutes. After that, the RF power supply is turned off, the glow discharge is stopped, and S in the deposition chamber 417 is stopped.
The inflow of iH ₄ / H ₂ (dilution degree: 1000 ppm) gas was stopped, H ₂ gas was continuously flowed into the deposition chamber 417 for 3 minutes, and then the inflow of H ₂ gas was also stopped, and the deposition chamber 4
The inside of 17 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Then, by the same method as in Example 2, a-Si
An n / i buffer layer 352 made of a, an MWi type layer 307 made of a-SiGe, ap / i buffer layer 362 made of a-Si, an RF p type layer 308 made of a-SiC,
The RFn-type layer 309 made of μc-Si was sequentially formed.

Next, the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention was performed. (Table 18 (4)) In order to carry out the hydrogen plasma treatment containing a small amount of silane-based gas of the present invention, SiH ₄ / H ₂ (dilution: 1
000 ppm) gas and H ₂ gas are deposited in the deposition chamber 417.
It is introduced through a gas introduction pipe 429 into the inside of the chamber, and valves 441, 431 and 4 are provided so that the H ₂ gas flow rate becomes 500 sccm.
30 was opened, and it adjusted with the mass flow controller 436. The silicon atom-containing gas has a valve 442 so that the amount of SiH ₄ gas is 0.03% with respect to the total H ₂ gas flow rate.
432 was opened and adjusted with the mass flow controller 437. The pressure in the deposition chamber 417 was adjusted to 0.8 Torr by a conductance valve (not shown).
The substrate heating heater 410 is set so that the temperature of the substrate 490 becomes 230 ° C., and when the substrate temperature becomes stable,
Set the power of the RF power source 422 to 0.03 W / cm ³ ,
RF power was introduced to cause glow discharge in the plasma forming cup 420, and the minute amount of silane-based gas-containing hydrogen plasma treatment of the present invention was performed for 2 minutes. After that, the RF power supply is turned off, the glow discharge is stopped, and S in the deposition chamber 417 is stopped.
The inflow of iH ₄ / H ₂ (dilution degree: 1000 ppm) gas was stopped, H ₂ gas was continuously flowed into the deposition chamber 417 for 3 minutes, and then the inflow of H ₂ gas was also stopped, and the deposition chamber 41
The inside of 7 and the inside of the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

Then, a-Si is formed by the same method as in the second embodiment.
An n / i buffer layer 353 made of C, an RF i type layer 310 made of a-Si, a p / i buffer layer 363 made of a-SiC, and an RF p type layer 311 made of a-SiC were sequentially formed by the RFPCVD method.

Next, on the RF p-type layer 311, as the transparent conductive layer 312, ITO having a layer thickness of 70 nm was vacuum-deposited by a vacuum deposition method.

Next, a mask having comb-shaped holes is placed on the transparent conductive layer 312, and Cr (40 nm) / Ag (1000 n
m) / Cr (40 nm) comb-shaped collector electrode 313
Was vacuum deposited by the vacuum deposition method.

Thus, the production of the solar cell was completed. This solar cell will be referred to as (SC Ex. 18), and the trace amount silane-based gas-containing hydrogen plasma treatment conditions of the present invention, RF n-type layer, n
/ I buffer layer, MWi type layer, p / i buffer layer,
The formation conditions of the RFi type layer and the RFp type layer are shown in Tables 18 (1) to 1
8 (5).

Comparative Example 18 A solar cell (SC ratio 18) was produced under the same conditions as in Example 18 except that the hydrogen plasma treatment containing a trace amount of silane-based gas of the present invention was not carried out.

Solar cell (SC Ex 18) and (SC ratio 1
8) were prepared for each of 7 pieces, and the initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, vibration deterioration in a high temperature and high humidity environment when a bias voltage was applied, and light deterioration were measured. .

The initial photoelectric conversion efficiency can be obtained by placing the manufactured solar cell under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristic. As a result of the measurement, the fill factor (FF) of the initial photoelectric conversion efficiency and the characteristic unevenness of (SC Ex 18) with respect to (SC Ratio 18) were as follows.

[0248] For the measurement of vibration deterioration, a solar cell whose initial photoelectric conversion efficiency was measured in advance was installed in a dark place with a humidity of 50% and a temperature of 25 ° C.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
It was determined by the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration deterioration test / initial photoelectric conversion efficiency).

Photodegradation was measured by setting a solar cell whose initial photoelectric conversion efficiency had been measured in advance in an environment of humidity 50% and temperature 25 ° C. and applying AM-1.5 (100 mW / cm ² ) light. AM1.5 (100 mW / cm after irradiation for 500 hours
² ) The rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after photodegradation test / initial photoelectric conversion efficiency) was used. As a result of the measurement, the reduction rate of the photoelectric conversion efficiency after the photodegradation and the reduction rate of the photoelectric conversion efficiency after the vibration degradation of (SC ratio 18) to (SC ex. 18) were as follows.

[0250] We measured vibration deterioration and light deterioration under high temperature and high humidity environment with bias applied. Two solar cells whose initial photoelectric conversion efficiency was measured in advance were placed in a dark place with a humidity of 90% and a temperature of 80 ° C., and 0.7 V was applied as a forward bias voltage. The above vibration was applied to one solar cell to measure the vibration deterioration, and the other solar cell was irradiated with light of AM1.5 to measure the light deterioration.

As a result of the measurement, (SC Ex 18),
Reduction rate of photoelectric conversion efficiency after vibration deterioration of (SC ratio 18),
The rate of decrease in photoelectric conversion efficiency after photodegradation was as follows. The state of delamination was observed using an optical microscope. In (SC Ex. 18), no delamination was observed, but (SC ratio 18)
A slight delamination was observed in.

As described above, the solar cell of the present invention (SC Ex 1
It was found that 8) had more excellent characteristics in the photoelectric conversion efficiency of the solar cell, unevenness in characteristics, photodegradation characteristics, adhesion, and durability than the conventional solar cell (SC ratio 18).

In the above embodiments, the n-type layer, n /
The solar cell in which the i-buffer layer, the i-type layer, the p / i buffer layer, and the p-type layer are stacked in this order has been described. The p-type layer, the p / i buffer layer, the i-type layer, and the n / i buffer layer are formed on the substrate. , The n-type layer was laminated in this order, and the solar cell treated with hydrogen plasma between the n-type layer and the n / i buffer layer was also manufactured and evaluated in the same manner, and similar excellent results were obtained. It was confirmed that

[0254]

[Table 1 (1)]

[0255]

[Table 1 (2)]

[0256]

[Table 2 (1)]

[0257]

[Table 2 (2)]

[0258]

[Table 2 (3)]

[0259]

[Table 3 (1)]

[0260]

[Table 3 (2)]

[0261]

[Table 3 (3)]

[0262]

[Table 3 (4)]

[0263]

[Table 4 (1)]

[0264]

[Table 4 (2)]

[0265]

[Table 4 (3)]

[0266]

[Table 5 (1)]

[0267]

[Table 5 (2)]

[0268]

[Table 5 (3)]

[0269]

[Table 6 (1)]

[0270]

[Table 6 (2)]

[0271]

[Table 6 (3)]

[0272]

[Table 7 (1)]

[0273]

[Table 7 (2)]

[0274]

[Table 7 (3)]

[0275]

[Table 8 (1)]

[0276]

[Table 8 (2)]

[0277]

[Table 8 (3)]

[0278]

[Table 9 (1)]

[0279]

[Table 9 (2)]

[0280]

[Table 9 (3)]

[0281]

[Table 10 (1)]

[0282]

[Table 10 (2)]

[0283]

[Table 10 (3)]

[0284]

[Table 11 (1)]

[0285]

[Table 11 (2)]

[0286]

[Table 11 (3)]

[0287]

[Table 12 (1)]

[0288]

[Table 12 (2)]

[0289]

[Table 12 (3)]

[0290]

[Table 13 (1)]

[0291]

[Table 13 (2)]

[0292]

[Table 13 (3)]

[0293]

[Table 14 (1)]

[0294]

[Table 14 (2)]

[0295]

[Table 14 (3)]

[0296]

[Table 15 (1)]

[0297]

[Table 15 (2)]

[0298]

[Table 15 (3)]

[0299]

[Table 16 (1)]

[0300]

[Table 16 (2)]

[0301]

[Table 16 (3)]

[0302]

[Table 17 (1)]

[0303]

[Table 17 (2)]

[0304]

[Table 17 (3)]

[0305]

[Table 18 (1)]

[0306]

[Table 18 (2)]

[0307]

[Table 18 (3)]

[0308]

[Table 18 (4)]

[0309]

[Table 18 (5)]

[0310]

According to the present invention, impurities (for example, oxygen, nitrogen, carbon, iron and chromium) which become defect levels when adsorbed on the wall surface of a deposition chamber or contained in a semiconductor layer which is usually contained in a hydrogen plasma treatment are obtained. , Nickel, aluminum, etc.) can be solved. In addition, stable hydrogen plasma treatment can be performed. As a result, 1) it is possible to provide a photovoltaic element in which the semiconductor layer is not substantially peeled off when the photovoltaic element is placed in high temperature and high humidity.

2) When a pin structure is formed on a flexible substrate, it is possible to provide a photovoltaic element in which the pin semiconductor layer is less likely to peel off even if the substrate is bent.

3) It is possible to provide a photovoltaic element in which an increase in the defect level near the interface between the substrate and the semiconductor layer is suppressed by long-time light irradiation.

4) It is possible to provide a photovoltaic element in which the substrate and the semiconductor layer are not separated even when irradiated with light under high temperature and high humidity and in which characteristic deterioration such as increase in series resistance is suppressed.

5) It is possible to prevent the diffusion of impurities from the n-type layer to the i-type layer and to provide a photovoltaic element with improved initial efficiency.

6) It is possible to provide a photovoltaic element with little deterioration in characteristics even when used at a high temperature.

7) It is possible to provide a photovoltaic element that is not easily broken when a reverse bias is applied to the photovoltaic element.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a photovoltaic element to which the method for forming a photovoltaic element of the present invention is applied.

FIG. 2 is a schematic explanatory view of another photovoltaic element to which the method for forming a photovoltaic element of the present invention is applied.

FIG. 3 is a schematic explanatory view of another photovoltaic element to which the method for forming a photovoltaic element of the present invention is applied.

FIG. 4 is a schematic explanatory diagram of a photovoltaic device forming apparatus suitable for the method for forming a photovoltaic device of the present invention.

[Explanation of symbols]

100, 200, 300 support, 101, 201, 301 reflective layer (or transparent conductive layer), 102, 202, 302 reflection increasing layer (or antireflection layer), 103, 203, 303 first n-type layer (or p-type layer), 104, 204, 304 first i-type layer, 105, 205, 305 first p-type layer (or n-type layer), 112, 212, 312 transparent conductive layer (or conductive layer), 113 , 213, 313 collector electrode, 151, 251, 351 first n / i buffer layer, 161, 261, 361 i-th p / i buffer layer, 206, 306 second n-type layer (or p-type layer) ), 207, 307 second i-type layer, 208, 308 second p-type layer (or n-type layer), 252, 352 second n / i buffer layer, 262, 362 second p / i buffer layer 309 Third n (or p-type layer), 311 Third p-type layer (or n-type layer), 310 Third i-type layer, 353 Third n / i buffer layer, 363 Third p / i buffer layer, 400 forming apparatus, 401 load chamber, 402, 403, 404 transfer chamber, 405 unload chamber, 406, 407, 408, 409 gate valve, 410, 411, 412 substrate heating heater, 413 substrate transfer Rail, 417 n-type layer (or p-type layer) deposition chamber, 418 i-type layer deposition chamber, 419 p-type layer (or n-type layer) deposition chamber, 420,421 plasma forming cup, 422, 423, 424 power supply , 425 microwave introduction window, 426 waveguide, 427 shutter, 428 bias rod, 429,449 469 gas inlet tube, 430,431,432,433,434,441,4
42,443,444,450,451,452,4
53, 454, 455, 461, 462, 463, 4
64, 465, 468, 466, 470, 471, 47
2,473,474, 481,482, 483,48
4 valves, 436, 437, 438, 439, 456, 457, 4
58, 459, 460, 467, 476, 477, 4
78,479 Mass flow controller, 490 Substrate holder.

Claims (4)

[Claims] 1. A non-single-crystal n-type layer (or p-type layer) containing a silicon atom, a non-single-crystal i-type n / i buffer layer (or p / i buffer layer), and a non-single crystal on a substrate. i
Type layer, non-single crystal i-type p / i buffer layer (or n /
i buffer layer) and non-single crystal p-type layer (or n-type layer)
In a method of forming a photovoltaic device in which at least one or more pin structures formed by stacking a plurality of layers are stacked, a silicon atom that does not substantially deposit near an interface where the n / i buffer layer and the n-type layer are in contact with each other is formed. A method for forming a photovoltaic element, which comprises performing a plasma treatment with hydrogen gas containing a contained gas. 2. A plasma treatment is carried out in the vicinity of the interface between the substrate and the n-type layer (or in the vicinity of the interface between the substrate and the p-type layer) with hydrogen gas containing a silicon atom-containing gas that is not substantially deposited. The method for forming a photovoltaic element according to claim 1, wherein 3. The silicon atom-containing gas is Si
_{H 4, Si 2 H 6,} SiF 4, SiFH 3, SiF 2 H 2, S
The method for forming a photovoltaic element according to claim 1, comprising at least one of iF ₃ H, SiCl ₂ H ₂ , SiCl ₃ H, and SiCl ₄ . 4. The method of forming a photovoltaic element according to claim 1, wherein the content of the silicon atom-containing gas with respect to the hydrogen gas is 0.1% or less. .