JPS6382424A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a sensitive body having high dark resistivity by changing the ratio of acetylene to Si in a gas during the formation of a film so that an amorphous silicon carbide layer formed is composed of at least four layered regions contg. C under specified conditions. CONSTITUTION:An a-SiC forming gas is decomposed by glow discharge to form a positively chargeable photoconductive a-SiC layer 5c on a substrate 1. The gas contains C2H2 and Si in 0.01:1-3:1 ratio. During the formation of the a-SiC layer 5c, the ratio of C2H2 to Si is changed so that the layer is composed of first, second, third and fourth layered regions 6, 7, 8, 9 formed in order from the substrate 1 side toward the surface of the resulting sensitive body. The amount of C in the third region 8 is made smaller than that in the fourth region 9 and larger than that in the second region 7. When the second region 7 is formed, 10<-6>-1mol% gas contg. a group IIia element is added to the a-SiC forming gas. When the first region 6 is formed, the gas contg. the group IIIa element is added by a larger amount than the amount in case of the second region 7. The regions 6-9 are practically integrated into the photoconductive a-SiC layer 5c.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an electrophotographic photoreceptor comprising a photoconductive amorphous silicon carbide layer, and particularly relates to a method for manufacturing an electrophotographic photoreceptor that can be positively charged. be.

[Prior art and its problems]

In recent years, progress in electrophotographic photoreceptors has been remarkable, and with the development of copying machines and printers equipped with photoreceptors, various characteristics are required of the photoreceptors themselves. It is attracting attention because of its excellent properties such as hardness, abrasion resistance, non-pollution, and photosensitivity.

However, the amorphous silicon (hereinafter abbreviated as a-Si) layer can only obtain a dark resistance value of about 10'Ωcm unless it is doped with any impurity element, and is used in electrophotographic photoreceptors. In some cases, it is necessary to increase the charge retention ability by increasing the dark resistance value to 10 Ω·cm or more. For this purpose, it is possible to increase the resistance by doping a small amount of elements such as oxygen or nitrogen, but on the other hand, there is a problem that the photoconductivity decreases.Additionally, even if boron is added, high resistance can be expected. However, a sufficiently satisfactory dark resistance value cannot be obtained, and is only about 10''Ω·cm.

On the other hand, along with the development of doping agents as mentioned above, a-Si
A laminated photoreceptor has been proposed in which a photoconductive layer is laminated with another non-photoconductive layer.

For example, Figure 2 shows this laminated photoreceptor, with the substrate (1)
A carrier injection blocking layer (2), an a-Si photoconductive layer (3) and a surface protection layer (4) are sequentially laminated thereon.

According to this laminated photoreceptor, the carrier injection blocking layer (2)
The surface protection layer (4) protects the a-5L photoconductive layer (3) and improves moisture resistance, etc., but the Layer (2
) and (4) are both intended to increase the dark resistance value of the photoreceptor to increase the charging ability, and for that purpose, it is not necessary to make these layers photoconductive.

As described above, the conventionally well-known A-3I electrophotographic photoreceptor has a major feature in that the photocarrier generation layer is formed by the A-3I photoconductive layer, and as a result, it has excellent heat resistance, durability, and photosensitivity characteristics. However, since the dark resistance value is insufficient, the dark resistance value is increased by using a doping agent or by forming a laminated type photoreceptor. That is, the carrier injection blocking layer (2
) and the surface protective layer (4) complement the defects of the a-Si photoconductive layer itself, and the a-5i photoconductive layer (3)
It can be said that it is a layer that can be practically distinguished.

[Purpose of the invention]

In view of the above circumstances, the present inventors conducted intensive research and found that amorphous silicon carbide (hereinafter referred to as a-3iC-) obtained by glow discharge decomposition of a mixed gas containing acetylene and silicon-containing gas at a certain ratio (omitted) has photoconductivity and has a dark resistance value of easily 1013 Ω·cm or more regardless of the presence or absence of a doping agent, and can also be an electrophotographic photoreceptor that can be positively charged by selecting a doping agent. I found it.

Therefore, the present invention was completed based on the above findings, and its purpose is to provide a photoconductive a-S having a large dark resistance value.
An object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor comprising an iC layer.

Another object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor that substantially eliminates the need for a surface protective layer and a carrier injection blocking layer and is composed of photoconductive a-3iC throughout the entire layer.

Still another object of the present invention is to provide a method for producing an electrophotographic photoreceptor that can be positively charged.

Still another object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor that achieves high-speed film formation.

[Means for solving problems]

According to the present invention, the gas contains at least acetylene (Cdb) and silicon (Si), and the gas composition ratio is set within the range of 0.01:1 to 3:1, and 1
Forming a positively chargeable a-SiC layer on a substrate by glow discharge decomposition of an a-3iC generation gas containing a gas containing 0-" to 1 mol χ of group rfia of the periodic table. A method for producing a featured electrophotographic photoreceptor is provided.

The present invention will be explained in detail below.

According to the production method of the present invention, Ct
Photoconductive a-3 on the substrate from Ht gas and Si-containing gas
When an iC layer is formed, a large dark resistance value can be obtained, and when it contains 10-' to 1 mol% of a gas belonging to Group Ma of the periodic table, it is positively charged. Figure 1 shows its basic characteristics. This is the photoreceptor that makes up the structure.

That is, according to FIG. 1, a photoconductive a-5iC layer (5) is formed on a conductive substrate (1) by a glow discharge decomposition method, and carbon and a periodic rule are formed over the thickness direction of this layer. The Ma group elements in the table (hereinafter abbreviated as Ma group elements) are contained in the same content ratio.

It was discovered that this resulted in a dark resistivity of 1013 co+・Ω or higher, which was also 1000 times higher than the bright resistivity. Practical a-
It was an unexpected result that a 5iC photoreceptor could be created.

Furthermore, when the present inventors charged this a-SiC photoreceptor to positive polarity or negative polarity and compared the charging performance of the two, they found that the Tfia group element was added to this a-5iC layer (5) by 0.1 to 10%.
,000ppm, preferably from 0.1 to 1000p
It has also been found that doping within the p- range can advantageously enhance the charging ability with positive polarity.

Although it is still a matter of speculation that doping or non-doping with Ma group elements makes it easier to charge positively, it is clear that the a-3iC layer has a sufficiently high resistivity to retain a positive charge. This is thought to be due to the fact that it has excellent durability and is also effective in preventing injection of negative charges from the substrate, and also has excellent charge mobility for positive charges.

In addition, this I[IIIa group element is B+AI+Ga
Among these, P is preferable because it has excellent covalent bonding properties and can sensitively change semiconductor characteristics, and is also desirable because it has excellent charging ability and sensitivity.

In doping with the Ma group element as described above, it is preferable that the a-3iC generation gas contains the Ma group element gas in an amount of 10-6 to 1 mol χ, preferably 10- to 0.1 mol χ, This makes it possible to dope within the above-mentioned required range.

In addition, when doping with ma group elements, BgH&,
BFz+ AI (CH3) sr Ga (CHs
) 3+ In (CHs) sr, etc. are used, and n*ni is particularly preferred.

Furthermore, in manufacturing the above-mentioned electrophotographic photoreceptor, the present inventors preferably mix C'tHt gas and Si-containing gas at a predetermined ratio based on a glow discharge decomposition method, thereby forming an a-3iC layer. It was discovered that the film can be formed at high speed and has photoconductivity.

That is, when introducing C*Ht and Si-containing gas into the glow discharge region, the gas composition ratio is set to 0.01:1 to 3:
l, preferably within the range of 0.05:1 to 1:1, optimally within the range of 0.05:1 to 0.3:1, and from a ratio of 0.01:1 to If it is off, the dark resistivity will be below IQIIΩ・CII+ and the charge retention ability will not be sufficient, making it impossible to obtain a large charged potential.
When the ratio deviates from 3:1, the number of dangling bonds in the film increases and the dark resistivity becomes less than IQIIΩ·cI11.

5iHa+5itHi+SiJ as the si-containing gas
@+5iPa.

There are 5iC1*, 5tHCh, etc., especially I S i
Ha + S 1 t Hb + itself is desirable because Si is bonded to H, so H is easily incorporated into the film, thereby reducing dangling bonds in the film, thereby improving photoconductivity.

Furthermore, when H is used as the dangling bond termination element, H! The gas should be mixed in an amount not more than 3 times, preferably not more than 2 times, the total flow rate of CtHt gas and SiH4 gas.If the amount exceeds this, hydrogen in the film will become excessive and the electrical power required for the photoreceptor will be reduced. Characteristics deteriorate.

According to the manufacturing method of the present invention, in producing the a-5iC layer under the manufacturing conditions as described above, the high frequency power for glow discharge, the gas pressure inside the reaction chamber, and the substrate temperature are set as follows. good.

In other words, the high frequency power should be set within the range of 0.05 to 0.5 W/c+w. If it is less than 0.05 W/cm, the deposition rate will be low, and if it exceeds 0.5 W/cm, the The film quality deteriorates due to plasma damage and carrier mobility decreases.In addition, the gas pressure is 0.1 to 2.0T.
If it is set within the range of 0.1 Torr, the film formation rate will be low, and if it exceeds 2.0 Torr, the discharge will become unstable. Furthermore, the substrate temperature is a-St:
The temperature should be about 30 to 80 degrees Celsius higher than the H film formation, preferably in the range of 200 to 400 degrees Celsius. If this substrate temperature is less than 200 degrees Celsius, the networking of Si and C will be inhibited. When the temperature exceeds 400°C, hydrogen desorption becomes significant and the dark resistivity decreases.

The reason why the a-3iC layer obtained by the manufacturing method of the present invention has photoconductivity is that amorphous silicon and carbon are essential constituent elements, and the dangling bonds are terminated. It is believed that photoconductivity is produced by containing H or a halogen element within a required range. The present inventors conducted experiments to confirm the presence or absence of photoconductivity by changing the content ratio of carbon in many ways, and found that 1 to 90 atoms of carbon χ
, preferably within the range of 5 to 50 atoms χ, or the carbon content may be varied within this range over the layer thickness direction.

In addition, the content of H and halogen elements is 5 to 50 atoms χ,
Preferably 5 to 40 atoms χ, optimally 10 to 30 atoms χ, and H is usually used. Since this H is easily incorporated into the terminal portion of the dangling bond, the localized level density in the band gap is reduced, thereby providing excellent semiconductor characteristics.

Further, a part of this H may be replaced with a halogen element, whereby the localized level density of the a-3iC layer can be lowered and the photoconductivity and heat resistance (temperature characteristics) can be improved. Its substitution ratio is 0.01 among all elements for dangling bond termination.
The number of atoms X is preferably from 1 to 50 atoms, preferably from 1 to 30 atoms χ. Further, the halogen element includes F+C1tBr+LAt, etc., and the use of F is particularly desirable because its large electronegativity increases the bonding between atoms, thereby providing excellent thermal stability.

Further, the thickness of the photoconductive a-5iC (5) should be at least 5 μm or more, so that the surface potential is 200 μm or more.
On the other hand, the upper limit of the thickness of N(5) is appropriately selected within the range of image resolution and image blurring, and according to experiments conducted by the present inventors, the thickness of N(5) is 5 to 100 V.
The thickness of μm is preferably set within the range of 10 to 50 μm.

When we determined the spectral sensitivity characteristics, dark decay curve, and light decay curve of this a-3iC layer, we found that the former has a spectral sensitivity peak (peak wavelength of approximately 670 nm) in the visible light region.
), and it has been found that this can be fully applied to tungsten lamps commonly used as light sources for copying machines. It was also found that the latter decay curve also had a high surface potential, excellent photosensitivity characteristics, and a small residual potential.

In this way, an electrophotographic photoreceptor is provided which can be put into practical use with just the photoconductive a-3iC layer having a single composition.

Next, based on the above results, the present inventors conducted further intensive research and discovered that the electrophotographic properties could be further improved by creating various layer regions within this single composition layer. Ta.

That is, in the manufacturing method of the present invention, the content ratio of carbon or Ma group elements is varied in the layer thickness direction during film formation by glow discharge decomposition, thereby generating a plurality of layer regions, and The following first to fourth aspects correspond to the numbers.
A method for manufacturing an electrophotographic photoreceptor according to the embodiments described above is obtained.

Hereinafter, the third embodiment of the method for manufacturing an electrophotographic photoreceptor according to the present invention will be described.
This will be explained with reference to Figures 24 to 24.

According to the first aspect of Hoshigami Tateharabo, there is provided a method for manufacturing an electrophotographic photoreceptor in which photoconductive a-5tCI, which can be positively charged, is formed on a substrate by glow discharge decomposition of a-3iC generation gas. The gas is composed of a gas containing CzHt and St, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and a gas containing a Ma group element is contained, and this content is removed during film formation. A method for manufacturing an electrophotographic photoreceptor characterized by a reduced ratio is provided.

That is, according to this first aspect, by incorporating the group a element into the photoconductive a-5iC layer having a single composition shown in FIG. 1, and changing the content ratio accordingly. At least a first layer region and a second layer region are generated, and this aspect will be explained with reference to FIGS. 3 to 9.

In FIG. 3, a first layer region (
6) and a second 1i region (7) are successively formed, both layer regions consisting of an integrated photoconductive a-3iC layer (5a), and a first IHI region (6) is formed. It is important that the second layer region (7) contains more UIa group elements than the second layer region (7).

The second N 9M region (7) has a content of ma group elements of 0.1
In the range from 10.000 ppm to 10.000 ppm, preferably from 0.1 to 1.

000 ppm, and as a result, it is charged to a negative polarity and required electrophotographic properties such as surface potential and photosensitivity properties are obtained. Then, a first layer region (6) containing more I[IIIa group elements than this layer region
When formed, the conductivity increases in the substrate-side region of the photoconductive a-5iC layer (5a), which prevents carrier injection from the substrate side and prevents carrier injection from occurring in the entire region of the a-SiC layer. It has been found that photocarriers flow smoothly to the substrate, resulting in an increase in surface potential and improved photosensitivity.

This first layer region (6) is photoconductive over its entire region, which makes it possible to avoid the conventional a shown in FIG.
It can be distinguished from the carrier injection blocking layer (2) of the -St electrophotographic photoreceptor.

That is, the first layer region (6) improves the photosensitivity characteristics over the entire layer due to the photoconductivity of the entire region. In particular, excellent photosensitivity characteristics can be obtained for relatively long wavelength light that easily reaches the first layer region (6), making it suitable for electrophotographic photoreceptors using semiconductor lasers as recording light sources. becomes.

Further, according to the conventional a-St electrophotographic photoreceptor, the layer thickness of the carrier injection blocking N(2) is changed to the layer thickness of the a-3i photoconductive layer (3).
), whereas according to the manufacturing method of the present invention, the layer thickness of the first N jJ (region (6)) is set to 1 times or less than that of the second layer region (7) Even if it is less than 1, the residual potential can be sufficiently reduced and the photosensitivity characteristics can be improved, and the preferred layer thickness ratio is preferably set to 172 or less, and optimally 1/4 or less.

The carbon content of this photoconductive a-5iC layer (5a) is as shown in FIGS. It shows the content. Note that (6) on this horizontal axis.

Each range shown in (7) represents a first layer region and a second layer region.

That is, in FIG. 4, the carbon content ratio is constant throughout the entire layer, or in FIG. 5, the carbon content is reduced in the first NELL region, whereas in FIGS. The figure shows that the first layer region contains more carbon than the second MW region, which further increases the surface potential (and improves the photosensitivity characteristics. If the carbon content is gradually changed in the layer thickness direction as shown in FIGS. 7 to 9, the surface potential and photosensitivity will be further increased and the residual potential will be reduced.

Further, the first N61 region (6) may contain a small amount of oxygen or nitrogen (or at least one kind of it).
The adhesion of the C layer (5a) to the substrate (1) is improved.

According to a second aspect of the invention, an electrophotographic photoreceptor is provided, in which a photoconductive a-SiC layer that can be charged to a positive polarity is formed on a substrate by glow discharge decomposition of an a-SiC generation gas. In the manufacturing method, the gas is C! At least a first region is formed in the a-5iC layer by setting a gas composition ratio of a gas containing Bg and St in a range of 0.01:1 to 3:1, and changing a composition ratio containing CJt during film formation. , a second M'pM region and a third region, the first N region is arranged closer to the substrate than the second layer region, and the second jileI region is arranged closer to the substrate than the third NTi1 region. The third N region contains more carbon than the second layer region, and when forming the second layer region, 10-'' to 1 mol χ of Ha group is added to the a-3iC generation gas. containing an element-containing gas and a during formation of the first layer region.
Provided is a method for manufacturing an electrophotographic photoreceptor, characterized in that the ratio of the Ma group element-containing gas in the -3iC generating gas is larger than that during the formation of the second NF4 region.

That is, according to this second aspect, as shown in FIG.
A third layer region (8) is further formed on the second layer region (7) shown in the first embodiment, and the carbon content of the third layer region (8) is accordingly increased. 2, and the first layer region (6), the second layer region (7) and the third layer region (8) are substantially integrated to form a photoconductive a −
A SiC layer (5b) was formed.

When this third layer region (8) is formed, the a-SiC layer (
It has been found that the dark resistance value on the surface side of 5b) increases, and the surface potential of the photoreceptor increases markedly.

This third layer region (8) is a photoconductive a-3iC layer (5b
) is formed to increase the resistance on the surface side, and is completely distinguishable from the conventionally known surface image ff1Ji(4) described in FIG. Furthermore, according to a functionally separated photoreceptor that is divided into a photocarrier generation layer and a carrier transport layer, the carrier transport layer can be 10'! Although the resistance is increased to Ω・0111 or higher, this layer is not required to have particularly high photoconductivity, and the ratio of photoconductivity to dark conductivity is usually 1.
The photoconductivity is set to be less than 1,000 times,
On the other hand, in the third layer region (8), this ratio is 100.
It has a photoconductivity of 0 times or more and can be sufficiently distinguished from the carrier transport layer.

The layer thickness of the third layer region (8) is not more than 1 times, preferably not more than 172 times, optimally not more than 17 times, compared to the second layer region (7).
4 times or less is preferable, and this can be said to be desirable because the surface potential is significantly improved, the photosensitivity is excellent, and the residual potential is small.

According to the present invention, the carbon content distribution of the photoconductive a-5iC layer (5b) is as shown in FIGS. 11 to 16, where the horizontal axis indicates the layer thickness direction from the substrate to the surface of the photoreceptor, The vertical axis shows carbon content. Furthermore, on this horizontal axis, (6
) (7) Each range shown in (8) represents a first layer region, a second N region, and a third layer region.

Figures 12, 14, 15, and 16 show that the carbon content is gradually changed in the layer thickness direction, which improves the surface potential, provides excellent photosensitivity, and reduces residual potential. .

According to a third aspect of the invention, there is provided a method for producing an electrophotographic photoreceptor in which a photoconductive a-StC layer that can be positively charged is formed on a substrate by glow discharge decomposition of an a-SiC generation gas. The gas is composed of CzHz and Si-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and the C and Ht composition ratios are changed during film formation. -3tC layer is provided with at least a first layer region, a second layer region, a third layer region and a fourth layer region in order from the substrate side toward the photoreceptor surface, and the third ONeI region is provided with a second layer region. Compared to the layer regions, the fourth layer region contains more carbon than the third layer region, and when forming the second layer region, 10 − to 1 mol 2 of carbon is added to the a-SiC generation gas. An electron containing a Ma group element-containing gas, and characterized in that the proportion of the Ma group element-containing gas in the a-SiC generation gas during formation of the first layer region is larger than that during formation of the second layer region. A method of making a photographic photoreceptor is provided.

That is, according to the third aspect, as shown in FIG.
A fourth layer region (9) is further formed on the third layer region (8) shown in B of FIG.
) contains more carbon than the third N region (8), and the first layer region (6) to the fourth layer region (9)
were substantially integrated to form a photoconductive a-SiC layer (5c).

This fourth layer region (9) contains more carbon than the third layer region (8) and has a high resistance, thereby increasing the charging ability and improving the surface potential. result,
A photoreceptor with high withstand voltage and long life can be obtained.

According to the manufacturing method of the present invention, the photoconductive a-SiC layer (5c)
The carbon content distribution of is as shown in FIGS. 18 to 21, where the horizontal axis indicates the layer thickness direction from the substrate to the photoreceptor surface,
The vertical axis shows carbon content. Note that on this horizontal axis, each range shown in (6), (7), (8), and (9) is the first l'! area, the second FJ area, the third layer area, and the fourth area.

In FIGS. 19 and 21, the carbon content is gradually changed in the layer thickness direction, thereby improving the surface potential and photosensitivity, and reducing the residual potential.

According to the embodiment shown in FIG.
! In the method for manufacturing an electrophotographic photoreceptor in which an a-SiC surface protective layer is sequentially formed, the photoconductive a-3iC generating gas is composed of czuz and a Si-containing gas, and the gas composition ratio is 0.01:1. to 3:1, and C, H! during film formation. The a-SiC layer is provided with at least a first layer region, a second layer region, and a third layer region by changing the content composition ratio, the first layer region being closer to the substrate than the second layer region,
The second layer regions are each disposed closer to the substrate than the third layer regions, and the third layer regions contain more carbon than the second regions, and when forming the second HfJ region, the a -Si
The C generating gas contains a gas containing 10-1 to 1 mol χ of a group element, and when forming the first layer region, a-SiC
Provided is a method for manufacturing an electrophotographic photoreceptor, characterized in that the proportion of the I[Ia group element-containing gas in the generation gas is larger than that during the formation of the second layer region.

That is, according to this fourth aspect, as shown in FIG.
Further a on the third layer region (8) shown in the second embodiment
-SiC surface protective layer (10) is formed, and this a-3iC surface protective layer (10) is made of photoconductive a-9iC
It is formed to overcoat and protect the surface of layer (5b).

The a-5iC surface protection layer (10) is the same as the photoconductive a-5iC layer (5b) in that it is made of a-SiC, but it has a high carbon content (and high hardness), which makes the surface hard. Provides protection.

This a-3iC surface protective layer (10) can be made photoconductive or non-photoconductive by changing the composition ratio of its constituent elements; increasing the carbon content tends to make it non-photoconductive. With this, high hardness characteristics are obtained, and high hardness is A-3.
It becomes an iC surface protective layer.

According to the fourth aspect, the carbon content distribution is shown in FIGS.
As shown in FIG. 4, the horizontal axis indicates the layer thickness direction from the substrate to the surface of the photoreceptor, and the vertical axis indicates the carbon content. Furthermore, on this horizontal axis (6) (7) (8) (10)
The respective ranges shown in the figure represent the first N'pM region, the second layer region, the third Ji fil region, and the a-SiC surface protective layer.

According to the present invention, the a-3iC layer of a single composition and the a-3iC layer of the first to third aspects are both photoconductive a-3iC layers.
3iC layers, which provide sufficient practical electrophotographic properties, but a conventionally known surface protective layer may be formed on the surface of these a-SiC layers.

Various materials can be used for this layer as long as they themselves have high insulating properties, high corrosion resistance, and high hardness properties, such as organic materials such as polyimide resin, a-5iC, 5
lOz + sto, A has + SiC, Si
3N4. , a-5i, a-Si:H, a-St
:P, a-3iC:H, Ha-5iC:F, and other inorganic materials can be used.

Next, a capacitively coupled glow discharge decomposition device used in an embodiment of the present invention will be explained with reference to FIG.

In the figure, 1st. Second. Third. 4th. Fifth. 6th tank (1
1) (12) (13) (14) (15) (16
) are SiH4 and CJt, respectively.

BtHh (contains 0.2χ with Hz gas dilution), BtH
h (contains 38pp when diluted with Hz gas), Hz, and NO gas are sealed, and H2 is also used as a carrier gas. These gases correspond to the first. Second. Third.
4th. Fifth. 6th regulating valve (17) (18) (19)
(20) (21) It is released by opening (22), and the flow rate is controlled by the mass flow controller (23).
(24), (25), (26), (27), and (28). Third. 4th. 5th tank (11
) (12) (13) (14) Gas from (15) goes to the first main pipe (29), N from the sixth tank (16)
O gas is sent to the second main pipe (30). Furthermore, (31) (
32) is a stop valve. Gas flowing through the first main pipe (29) and the second main pipe (30) is sent into the reaction tube (33), and a capacitively coupled discharge electrode (34) is installed inside this reaction tube (33). The high frequency power applied to it is 50 Kw to 3 Kw, and the frequency is IM
Hz to 10 MHz is suitable. Inside the reaction tube (33) is a cylindrical film-forming substrate (35) made of aluminum.
is placed on the sample holder (36), this holder (36) is rotated by a motor (37), and the substrate (35) is heated by suitable heating means. , uniformly heated to a temperature of about 200 to 400°C, preferably about 200 to 350°C. Furthermore, the reaction tube (
33) is in a highly vacuum state (
It is connected to a rotary pump (38) and a diffusion pump (39) by requiring a ground voltage of 0.1 to 2.0 Torr.

In the glow discharge decomposition device configured as above,
For example, an a-3iC film (containing B) is placed on the substrate (35).
1. Second. Third. Fifth regulating valve (
17) (1B) (19) Open (21) and release SiH4°CzHz and BJ&Hz gas from each. The amount of release is determined by the mass flow controller (23) (24)
(25) Controlled by (27), SiH*, CJ
The mixed gas of g, BJi, and Hz is flowed into the reaction tube (33) through the first main pipe (29). Then, the reaction tube (
33) is in a vacuum state of about 0.1 to 2.0 Torr, the substrate temperature is 200 to 400°C, the high frequency power of the capacitive discharge electrode (34) is set to 50 to 3 KM, or the frequency is set to 1 to 10 MHz. In conjunction with this, a glow discharge occurs, and the gas decomposes into a-
A SiC film is formed on the substrate at high speed.

〔Example〕

Next, embodiments of the present invention will be described in detail.

(Example 1) In this example, a photoconductive a-SiC layer is produced on an aluminum deposition substrate, and its Ct)! The conductivity was measured with respect to the blending ratio of t-gas.

That is, using the capacitively coupled glow discharge decomposition device shown in FIG.
secta, H2 gas is released from the fifth tank (15) at a flow rate of 300sccn+, and the second tank (12
), the cztit gas was released at a flow rate of 10 to 101005 c, and a
When a -SiC film was produced and its dark conductivity and photoconductivity were measured, the results shown in FIG. 26 were obtained. The manufacturing conditions are a substrate temperature of 300℃ and a gas pressure of 0.4℃.
The high frequency power was set at 5 Torr and 15 Torr.

According to FIG. 26, the horizontal axis shows C, H, gas flow rate (sccm
), the vertical axis represents the conductivity [(Ω・c+++)-'), the mark is a plot of dark conductivity, the mark Q is a plot of photoconductivity, and a and b are the respective characteristic curves. .

As is clear from Fig. 26, the dark conductivity is 10-'' (
It can be more than 10-''(Ωcm)-' at maximum
・co+)-' or higher was obtained. In addition, the photoconductivity is more than 1000 times that of the dark conductivity, and this a-SiC
It can be seen that the layer has sufficiently satisfactory photoconductivity for use in electrophotographic photoreceptors.

(Example 2) In this example, when BzHb gas (or PHs gas) was introduced and the dark conductivity and photoconductivity were measured based on (Example 1), the results shown in Figure 27 were obtained. Ta.

In the figure, the horizontal axis is BJi relative to the total flow rate of SiL and CJg.
The pure amount (this is the absolute flow rate of B, H, calculated from the dilution ratio of H2 gas). Furthermore, B.
A case where the pure amount of H6 is replaced with the pure amount of pus is also described as a reference example.

According to FIG. 27, the mark is a plot of dark conductivity,
O mark is a plot of photoconductivity, and c and d are respective characteristic curves.

As is clear from Fig. 27, the photoconductivity is more than 1000 times that of the dark conductivity, and the a-
The 3iC layer has satisfactory photoconductivity for use in electrophotographic photoreceptors.

(Example 3) In this example, (Example 1) medium CtHz gas flow rate is 101
The spectral sensitivity characteristics of the a-5iC layer obtained with the setting of 05e were measured, and the results were the spectral sensitivity curve e shown in FIG. Note that this figure shows the photoconductivity when irradiated with equal energy light at each wavelength.

As is clear from FIG. 28, photosensitivity is observed in the visible light region, and as a result, it can be satisfactorily used as a photoconductor for electrophotography.

(Example 4) In this example, (Example 1) medium CJz gas flow rate is 10sc
a-SiC layer obtained by setting ca+ (thickness 30μ+
For 1), the characteristics of surface potential, dark decay, and light decay were measured. This measurement was performed using a +5.6KV corona charger to positively charge the surface potential, and the change in surface potential over time in the dark.
This figure follows the change in surface potential over time immediately after irradiation with 50na+ monochromatic light.

The results are shown in FIG. 29, where Lg is the dark decay curve and the light decay curve, respectively.

As is clear from FIG. 29, the surface potential is as large as about +600V, and the dark decay is about 25χ after 5 seconds, indicating excellent charge retention ability. It can also be said that it has excellent photoconductivity and low residual potential.

In addition, the a-SiCN obtained in (Example 4) was heated to -5.6 KV.
When negatively charged with a corona charger, the surface potential was several tens of volts.

And a-SiC manufactured based on this (Example 4)
The layered photoreceptor was positively charged with a +5.6KV corona charger, and then exposed to image light to perform a magnetic brush phenomenon. As a result, a high-quality image with high image density and contrast was obtained, and the process was repeated 200,000 times. Even after the test, no deterioration of the initial image was observed, and it was confirmed that the durability was good.

(Example 5) In this example, a photoreceptor of the first embodiment was manufactured.

That is, the aluminum drum for the substrate is installed in the reaction tube (33) of the capacitively coupled glow discharge decomposition device shown in FIG. ), BzHi gas from the third tank (13), and H! gas from the fifth tank (15). Gas and NO gas were released from the sixth tank (16), respectively, and the first M fil region and the second layer region were formed under the manufacturing conditions shown in Table 1.

The electrophotographic properties of the photoreceptor thus obtained were +5 in the dark.
．． It was positively charged in a corona charge connected to a 6KV high voltage source, and then the monochromatic light (650n+m
) was irradiated onto the surface of the photoreceptor, and the following characteristics were obtained. Note that the residual potential is the value 5 seconds after the start of exposure.

Surface potential: +700v Photosensitivity: 4.38cm"erg-' Residual potential: 25V (Example 6) In this example, a photoreceptor of the second embodiment was manufactured under the conditions shown in Table 2. The following electrophotographic properties were obtained.

Surface potential...+760■ Photosensitivity...0.40cm"erg-'Residual potential...
30V (Example 7) In this example, a photoreceptor of the third embodiment was manufactured under the conditions shown in Table 3, and the following electrophotographic characteristics were obtained.

Surface potential...+820■ Light sensitivity...0.42CI! erg-1 Also, the characteristics of the surface potential, dark decay, and light decay of this photoreceptor are (
As a result of measurement in the same manner as in Example 4), the results shown in FIG. 30 were obtained. In FIG. 30, h and i are the dark decay curve and the light decay curve, respectively.

As is clear from FIG. 30, the surface potential is significantly large, approximately +820V, and the dark decay is approximately 8χ after 5 seconds, indicating excellent charge retention ability.

(Example 8) In this example, a photoreceptor of the fourth embodiment was manufactured under the conditions shown in Table 4, and the following electrophotographic characteristics were obtained.

(Example 9) In this example, the film formation rate was measured under the following manufacturing conditions using the glow discharge decomposition apparatus shown in FIG. 25, and the results shown in FIG. 31 were obtained.

Seika RF power...150W Gas pressure--0.45Torr Substrate temperature...300℃ 5iHi gas flow rate...1003cc11H snow gas flow rate...300sccll The circles in Figure 31 are plots of measurement results. and j is its characteristic curve.

As is clear from FIG. 31, as the content ratio of cant gas increases, the film forming rate increases, reaching a film forming rate of about 5 to 13 μ-7.

(Example 10) In this example, C
, H, and the hydrogen content in the film while changing the content ratio of the gases, the results shown in FIG. 32 were obtained.

In FIG. 32, the marks ◯ and * are plots showing the amount of H bonded to C and St, respectively, and k and 1 are their characteristic curves, respectively.

As is clear from Figure 32, C! As the content ratio of Hz gas becomes thicker, the number of C-H bonds increases and 5-
It can be seen that the 1t coupling decreases.

〔Effect of the invention〕

As described above, according to the method for manufacturing an electrophotographic photoreceptor of the present invention,
Since a-5iC, which has photoconductivity throughout the entire layer, has a high dark resistance value and excellent photosensitivity characteristics, it is possible to substantially eliminate the need for a surface protective layer and a carrier injection stop layer. As a result, an electrophotographic photoreceptor consisting only of a photoconductive a-SiC layer could be provided.

Furthermore, according to the manufacturing method of the present invention, a significantly high film formation rate can be obtained by glow discharge decomposition using a combination of CgHx gas and Si-containing gas, thereby improving manufacturing efficiency and manufacturing cost.

Furthermore, according to the manufacturing method of the present invention, by changing the content of carbon and Ma group elements in the layer thickness direction, it is possible to improve the surface potential, enhance the photosensitivity characteristics, and significantly reduce the residual potential. can.

In particular, when the carbon content is varied in the layer thickness direction, the resistivity can be controlled and a desired layer area can be obtained, and as a result, an electrophotographic photoreceptor with significantly higher performance can be provided.

Further, according to the manufacturing method of the present invention, a positive polarity electrophotographic photoreceptor that can be charged advantageously to positive polarity is provided.

Furthermore, when a conventional a-Si photoreceptor is used for a long period of time, local discharge damage on the surface of the photoreceptor is likely to occur due to corona discharge, which causes spots on the image. However, according to the manufacturing method of the present invention, a
-5t has a dielectric constant of ε-12, while a-5iC
Since ε=7, which is about half, it has excellent charging ability.As a result, the above-mentioned discharge breakdown does not occur even if the surface potential is increased, and as a result, high-quality and highly reliable electronic A photographic photoreceptor is provided.

Further, according to the method for producing an electrophotographic photoreceptor of the present invention, since it has excellent charging ability and environmental resistance by itself, there is no need to provide a special protective layer, and, for example, it is not necessary to provide a protective layer due to exposure to corona discharge or the resin component of the developer. When the surface of a photoconductor is deteriorated due to filming, etc., the initial characteristics of the photoconductor can be maintained without being limited in the amount of polishing even if the deteriorated surface is repeatedly polished and regenerated with an abrasive. This makes it possible to stably supply a good initial image over a long period of time.

Furthermore, when the electrophotographic photoreceptor obtained by the manufacturing method of the present invention is compared with a conventional a-Si photoreceptor, the problem with this a-Si photoreceptor is that it is inferior in moisture resistance and tends to cause image deletion. Furthermore, since the charging ability is poor, a ghost phenomenon occurs, but in order to solve this problem, a heater is used to heat the photoreceptor when using the a-3t photoreceptor, thereby preventing the occurrence of this phenomenon. On the other hand, the electrophotographic photoreceptor according to the manufacturing method of the present invention has excellent moisture resistance and charging ability, and therefore has the advantage that it does not require the use of a heater as described above.

Furthermore, compared to the a-St photoreceptor, the manufacturing method of the electrophotographic photoreceptor of the present invention allows a wide range of spectral sensitivity characteristics (peak 600 to 700 nm) to be obtained by simply changing the carbon content, and it is also possible to increase the photosensitivity itself. Furthermore, there is an advantage that sensitization on the long wavelength side is also possible by doping with an impurity element as necessary.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the layer structure of an electrophotographic photoreceptor according to the manufacturing method of the present invention, FIG. 2 is an explanatory diagram showing the layer structure of a conventional electrophotographic photoreceptor, and FIG. 4, 5, 6, and 7
8 and 9 are explanatory diagrams showing the carbon content of the photoreceptor of the first embodiment of the present invention, respectively, and FIG. 10 is an explanatory diagram showing the layer area of the photoreceptor of the second embodiment of the invention. 11, 12, 13, 14, 15, and 16 are explanatory diagrams showing the carbon content of the photoreceptor of the second embodiment of the present invention, respectively. Figure 17 is the third diagram according to the present invention.
An explanatory diagram showing the N area of the photoreceptor in the embodiment, FIG.
9, FIG. 20, and FIG. 21 are explanatory views showing the carbon content of the photoreceptor of the third embodiment of the present invention, respectively, and FIG. 22 is a layer region of the photoreceptor of the fourth embodiment of the present invention. FIG. 23 and FIG. 24 are explanatory diagrams showing the carbon content of the photoreceptor of the fourth embodiment of the present invention, and FIG. 25 is a capacitively coupled glow discharge used in the embodiment of the present invention. An explanatory diagram of the decomposition device, Fig. 26 is a diagram showing the conductivity with respect to the flow rate ratio of C7Ht gas, Fig. 27 is a diagram showing the conductivity with respect to the flow rate ratio of PH, gas, and BzHh gas, and Fig. 2
FIG. 8 is a diagram showing the spectral sensitivity characteristics of the amorphous silicon carbide layer, FIG.
Figure 31 is a diagram showing the dark attenuation and optical attenuation of the amorphous silicon carbide layer in the embodiment, Figure 31 is a diagram showing the film formation rate with respect to the flow rate ratio of C, H, and gases, and Figure 32 is a diagram showing the film formation rate with respect to the flow rate ratio of CzHz gas. FIG. 3 is a diagram showing the bonding ratio of atoms. 1...Substrates 5.5a, 5b, 5c...Photoconductive amorphous silicon carbide layer 6...First layer region 7...Second layer region 8...Third layer region 9...Fourth layer region 10...Amorphous silicon carbide surface protective layer Patent applicant (663) Kyocera Corporation Takao Kawamura

Claims (3)

[Claims] (1) A method for producing an electrophotographic photoreceptor in which a photoconductive amorphous silicon carbide layer that can be positively charged is formed on a substrate by glow discharge decomposition of an amorphous silicon carbide generating gas, wherein the gas contains acetylene and silicon. containing gas, the gas composition ratio is set within the range of 0.01:1 to 3:1, and the acetylene content composition ratio is changed during film formation to form at least a first layer region on the amorphous silicon carbide layer; A second layer region, a third layer region, and a fourth layer region are sequentially provided from the substrate side toward the surface of the photoreceptor, and the third layer region is larger than the second layer region. Each layer region contains more carbon than the third layer region, and when forming the second layer region, the amorphous silicon carbide generating gas contains 10^-^6 to 1 mol% of Group IIIa of the periodic table. It is characterized by containing an element-containing gas and at the time of forming the first layer region, the proportion of the gas containing the Group IIIa element of the periodic table in the amorphous silicon carbide generating gas is larger than that at the time of forming the second layer region. A method for manufacturing an electrophotographic photoreceptor. (2) The method for manufacturing an electrophotographic photoreceptor according to claim (1), wherein the amorphous silicon carbide layer contains 1 to 90 atomic percent carbon. (3) The electrophotographic photoreceptor according to claim (1), wherein the amorphous silicon carbide layer contains 1 to 90 atomic % carbon and 5 to 50 atomic % hydrogen. Manufacturing method.