JPS6382420A - 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 negatively chargeable a-SiC layer 5c on a substrate 1. The gas contains C2H2 and Si in 0.01:1-3:1 ratio and the ratio of C2H2 to Si is changed so that the layer 5c 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, 0-1mol% gas contg. a group Va element is added to the a-SiC forming gas. When the first region 6 is formed, the gas contg. the group Va 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, so a sensitive body having high dielectric strength and a long service life can be obtd.

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 charged to a negative polarity. be.

[Prior art and its problems]

In recent years, progress in electrophotographic photoreceptors has been remarkable, and with the development of copying machines, printers, etc. equipped with photoreceptors, various characteristics are required of the photoreceptors themselves.

In response to this demand, amorphous silicon layers are attracting attention because they have excellent heat resistance, wear resistance, non-pollution properties, and photosensitivity characteristics.

However, the amorphous silicon (hereinafter abbreviated as a-31) layer can only obtain a dark resistance value of about 109 Ωcm unless it is doped with any impurity element, and when used in electrophotographic photoreceptors, To achieve this, it is necessary to increase the charge retention ability by setting a dark resistance value of 10 12 Ω·cam 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. Further, even if boron or the like is added, a high resistance can be expected, but a sufficiently satisfactory dark resistance value cannot be obtained and is only about 101'Ω·cn+.

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 N (4) are sequentially laminated thereon.

According to this laminated photoreceptor, the carrier injection blocking layer (2)
The surface protection layer (4) protects the a-Si photoconductive layer (3) and improves its moisture resistance, etc., but the N(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 surface image 8171(4) complement the defects of the a-St photoconductive layer itself, and the a-St photoconductive layer N(
It can be said that this layer is substantially distinguishable from 3).

[Purpose of the invention]

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

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 producing an electrophotographic photoreceptor that substantially eliminates the need for a surface protective layer and a carrier injection blocking layer and is made of photoconductive a-5iC throughout the entire layer.

Still another object of the present invention is to provide a method for producing an electrophotographic photoreceptor that can be negatively 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 (CJt) and silicon (St), and the gas composition ratio is set within the range of 0.01:1 to 3:1, and 0.01:1 to 3:1.
a containing gas containing 1 to 1 mole χ of Group Va elements of the periodic table
- A method for manufacturing an electrophotographic photoreceptor is provided, which comprises forming an a-SiC layer that can be charged to a negative polarity on a substrate by glow discharge decomposition of a -SiC generating gas.

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 Hz gas and Si-containing gas
When an iC layer is formed, a large dark resistance value can be obtained, and when it contains 0 to 1 mol% of a gas belonging to Group Va of the periodic table, it is negatively charged. Figure 1 shows its basic structure. It is a photoreceptor.

That is, according to FIG. 1, a photoconductive a-SiC plate (5) is formed on a conductive substrate (1) by, for example, a glow discharge decomposition method, and carbon and periodic particles are formed over the thickness direction of this layer. Group Va elements (hereinafter abbreviated as Va group elements) are contained in the same content ratio. It was discovered that this resulted in a dark resistivity of 10" cm Ω or more, which was also 1000 times higher than the bright resistivity. As is clear from the examples described below based on this knowledge, only this single composition layer It was an unexpected result that a fully practical a-3iC photoreceptor could be obtained.

Furthermore, when the present inventors charged this a-SiC photoreceptor to positive polarity or negative polarity and compared the charging performance of both, the Va group element was added to this a-3iC layer (5) from 0 to 10, OOO
It has also been found that doping in the ppm range, preferably in the range from 0 to 11000 ppm, can advantageously increase the chargeability with negative polarity.

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

In addition, the Va group elements include NtPtAs, Sb, B
Among them, P is preferable because it has excellent covalent bonding properties and can sensitively change the semiconductor properties, or even if it is non-doped, there are few constituent elements in the film (so stable properties can be obtained. Moreover, it is desirable in that it has excellent charging ability and sensitivity.

When doping the Va group element as described above, the a-5iC generation gas should contain O to 1 mol χ, preferably 0 to 0.1 mol χ of the Va group element gas. It becomes possible to dope within the above-mentioned required range.In addition, when doping with Va group elements, Nt, NH3, PH3, AsF3.SbH3
etc. are used.

The reason why the a-SiC layer obtained by the manufacturing method of the present invention becomes photoconductive is that it uses amorphous silicon and carbon as essential constituent elements, and furthermore, it uses PEH to terminate the dangling bonds. It is believed that photoconductivity occurs when the halogen element is contained within the required range.The inventors conducted experiments to confirm the presence or absence of photoconductivity by varying the content ratio of carbon. , 1 to 90 carbon atoms χ in the a-3iC layer (5)
, 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 ■ 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.

Furthermore, a part of this H may be replaced with a halogen element (thereby, the localized level density of the a-3iC layer can be lowered and the photoconductivity and heat resistance (temperature characteristics) can be improved. The substitution ratio is 0.01 among all elements for dangling bond termination.
50 atoms χ, preferably 1 to 30 atoms χ, and this halogen element includes F+CI+Br, 1. Although there are At and the like, F is particularly desirable because its large electronegativity increases the bonding between atoms, resulting in excellent thermal stability.

Further, the thickness of the photoconductive a-SiC (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 this layer (5) is appropriately selected within the range of image resolution and image blurring, and according to experiments by the present inventors, the thickness is 5 to 100 V.
pm, preferably within the range of 10 to 50 μn+.

When we determined the spectral sensitivity characteristics, dark decay curve, and light decay curve of this a-5iC layer, we found that the former has a spectral sensitivity peak (peak wavelength of approximately 600 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 had both a high surface potential and excellent photosensitivity characteristics, and also had a smaller residual potential.

Furthermore, in manufacturing the above-mentioned electrophotographic photoreceptor, the present inventors used C, Ht gas and S based on a glow discharge decomposition method.
It has been found that by mixing i-containing gases at a predetermined ratio, an a-SiC layer can be formed at high speed and has photoconductivity.

That is, CtH! When introducing the Si-containing gas into the glow discharge region, the gas composition ratio is set to 0.01:1 to 3;
1, preferably 0.05:1 to 1:1, optimally 0.05:1 to 0.3:1, and from a ratio of 0.01:1 to If it is off, the dark resistivity becomes less than IQIIΩ·am, and the charge retention ability is insufficient, making it impossible to obtain a large charged potential.3:
When the ratio deviates from 1, the number of dangling bonds in the film increases and the dark resistivity becomes less than IQIIΩ·Cl11.

SiH4,5iJ6,5i3H as the Si-containing gas
11, SIF*+5iC1a, 5iHC13, etc. Among them, 5tH4 and 5iJi+ have St bonded to H, so H is easily dissolved into the film, reducing dangling bonds in the film and improving photoconductivity. It is desirable in that it improves

Furthermore, when H is used as the element for terminating dangling bonds, Ht gas may be blended in an amount of 3 times or less, preferably 2 times or less, of the total flow rate of CJt gas and SiH4 gas; This results in excessive hydrogen in the film, deteriorating the electrical characteristics required of the photoreceptor.

According to the manufacturing method of the present invention, when producing a-3iCJi under the manufacturing conditions as described above, it is preferable to set the high-frequency power for glow discharge, the gas pressure inside the reaction chamber, and the substrate temperature as follows. .

That is, the high frequency power is 0.05 to 0.5 W/cm! If it is set within the range of < 0.05 W/cm'', the film formation rate will be low, and if it exceeds 0.5 W/cm'', the film quality will deteriorate due to plasma damage and the carrier mobility will decrease. In addition, the gas pressure is 0.1 to 2.0To
Just set it in the range of rr<, 0. If it is less than I 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-5t:H
The temperature is preferably about 30 to 80 degrees Celsius higher than the temperature for film formation, preferably in the range of 200 to 400 degrees Celsius. If the substrate temperature is less than 200° C., networking of St and C is inhibited, and if it exceeds 400° C., hydrogen desorption becomes significant and the dark resistivity decreases.

Thus, an electrophotographic photoreceptor is provided which can be put into practical use with just a photoconductive a-SiC 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 Va 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 a first aspect of the invention, an electrophotographic photoreceptor is provided, in which a photoconductive a-SiC layer that can be negatively charged is formed on a substrate by glow discharge decomposition of an a-5iC generation gas. In the manufacturing method, the gas is composed of a CtHz and Si-containing gas, the gas composition ratio is set within the range of 0.01:1 to 3:1, and a Va group element-containing gas is contained while the gas is Provided is a method for producing an electrophotographic photoreceptor characterized in that this content ratio is reduced.

That is, according to this first aspect, by incorporating a Va group element into the photoconductive a-SiC layer having a single composition shown in FIG. 1 and changing the content ratio accordingly, at least The tenth layer region and the 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 layer region (7) are successively formed, both layer regions consisting of an integrated photoconductive a-3iC layer (5a); It is important that the second layer region (7) contains more Va group elements than the second layer region (7).

The second NF4 region (7) has a Va group element content of O to 1.
Within the range of 0,000 ppm, preferably 0 to 1,00
It is suitably controlled within the range of 0 pp+m, 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, Va
When the first Nril region (6) containing a large amount of group elements is formed, the conductivity increases in the substrate side region of the photoconductive a-3iC layer (5a), thereby preventing carrier injection from the substrate side. It has been found that the photocarriers that are blocked and generated in the entire region of the a-3iC layer flow smoothly to the substrate, and as a result, the surface potential increases and the photosensitivity characteristics improve.

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 properties across the gold film 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 set to 3.
), whereas according to the manufacturing method of the present invention, the layer thickness of the first layer region (6) is set to be 1 times or less than that of the second layer region (7). Even if the residual potential is present, the residual potential can be sufficiently reduced to improve the photosensitivity characteristics, and the preferred layer thickness ratio is preferably set to 172 or less, and optimally 174 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 layer region, whereas in FIGS. indicates that the first layer region contains more carbon than the second layer region, which further increases the surface potential and improves the photosensitivity characteristics. Further, 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 layer region (6) may contain at least one of oxygen and nitrogen, so that the a-SiC
The adhesion of the layer (5a) to the substrate (1) is improved.

According to a second aspect of No. 2011, there is provided a method for manufacturing an electrophotographic photoreceptor in which a photoconductive a-SiC layer that can be charged to a negative polarity is formed on a substrate by glow discharge decomposition of an a-SiC generation gas. The gas is composed of CtHt and Si-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and the CJz-containing composition ratio is changed during film formation to form the a-SiC layer. At least a first region, a second layer region, and a third region are provided, the first layer region being closer to the substrate than the second layer region, and the second layer region being closer to the substrate than the third layer region. are placed respectively in
The third layer region contains more carbon than the second layer region, and when forming the second layer region, 0 to 1 mole χ of Va group element-containing gas is added to the a-3iC generation gas. A method for manufacturing an electrophotographic photoreceptor, characterized in that the proportion of Va group element-containing gas in the a-5iC generation gas during formation of the first layer region is larger than that during formation of the second layer region. provided.

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. 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. −
3iC layer (5b).

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 of the layer (4), and can be completely distinguished from the conventionally known surface protective layer (4) described in FIG. In addition, according to a functionally separated photoconductor that is divided into a photocarrier generation layer and a carrier transport layer, the carrier transport layer has a high resistance of 101ffΩ・Cl11 or more, but this layer is required to have exceptionally high photoconductivity. Usually, the ratio of photoconductivity to dark conductivity is 100.
The photoconductivity is only set to be less than 0 times. On the other hand, the third layer region (8) has a photoconductivity that is 1000 times higher in this ratio or more, and can be sufficiently distinguished from the carrier transport layer.

The layer thickness of the third layer region (8) is equal to the second I! layer area 7), preferably 172 times or less, optimally 1
A value of 74 times or less is good, and as a result, the surface potential is significantly improved, the photosensitivity is excellent, and the residual potential is small.
It can be said that it is desirable.

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) is the first IJ
Layer regions represent a second layer 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 photoconductive a-SiCl, which can be charged to a negative polarity, is formed on a substrate by glow discharge decomposition of a-3iC generation gas. The gas is composed of CtHz and Si-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and the C2H2 content ratio is changed during film formation to form the a-3tCN. includes 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 layer region is provided with a second layer region. Compared to the area, the fourth
Each of the layer regions contains more carbon than the third layer region, and when forming the second layer region, the a-3iC generation gas contains O to 1 mole χ of Va group element-containing gas, and Provided is a method for manufacturing an electrophotographic photoreceptor, characterized in that when forming the first layer region, the proportion of Va group element-containing gas in the a-SiC generating gas is larger than when forming the second layer region. .

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 the embodiment, and accordingly, a fourth layer region (9) is formed.
) contains more carbon than the third layer 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) is the third NTi1W region (8)
By containing a large amount of carbon to increase the resistance, it is possible to increase the charging ability and improve the surface potential, and as a result, it is possible to obtain a photoconductor with a high withstand voltage and a long life.

According to the manufacturing method of the present invention, photoconductive a-SiCJi (5c
) is as shown in FIGS. 18 to 21, where 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. In addition, on this horizontal axis, the respective ranges shown in (6), (7), (8), and (9) represent the first layer region, the second JW layer region, the third layer region, and the fourth region. There is.

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 fourth aspect of the plan, a photoconductive a-3tC layer that can be charged to a negative polarity and an a-SiC surface protection layer are sequentially formed by glow discharge decomposition of an a-SiC generation gas. In the method for manufacturing a photographic photoreceptor, the photoconductive a-SiC generating gas is composed of CtIh and Si-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1. C in the film
The a-SiC layer has at least a first layer region, a second layer region, and a third layer region by changing the zHz content composition ratio, and the first layer region is closer to the substrate than the second layer region. , second
The layer regions are arranged closer to the substrate than the third layer region, and the third layer region contains more carbon than the second layer region, and when forming the second layer region, the a-3iC The generation gas contains O to 1 mol χ of the Va group element-containing gas, and the proportion of the Va group element-containing gas in the a-3iC generation gas during the formation of the first layer region is the same as that of the second layer region. Provided is a method for manufacturing an electrophotographic photoreceptor characterized by a larger size than usual.

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 retention! This a-5iC surface protective layer (10) is a photoconductive a-5iC surface protective layer (10).
It is formed to overcoat and protect the surface of the SiC layer (5b).

The a-3iC surface protective layer (10) is the same as the photoconductive a-3iC layer (5b) in that it is made of a-3iC, but it has a higher carbon content to give it higher hardness, thereby protecting the surface. bring about action.

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 Figure 13 and Figure 2.
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 are the first layer region, the second layer region,
The third N fil region and a-3iC surface protection layer are shown.

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.
Although the a-5iC layer provides sufficient practical electrophotographic properties, a conventionally known surface protective layer may be formed on the surface of these a-5iC 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-SiC, 5
top, SiO+ Al 20s+ stc, si
sca, a-St + a-St: H+a-St:
Inorganic materials such as F+a-3iC:Iff and Ha-5iC:F 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, No. 2. Third. 4th. Fifth. 6th tank (11
) (12) (13) (14) (15) (16
), SiH*+CzHz+PHz (Ib
(contains 0.2χ when diluted with gas), PH* (contains 3 when diluted with Ib gas)
3ppm), H,, No gas is sealed,■
2 is also used as a carrier gas. These gases correspond to the first. Second. Third. 4th. Fifth. Sixth regulating valve (17) (18) (19) (20) (21) (
22), and its flow rate is controlled by the mass flow controllers (23), (24), (25), and (26).
(27) Controlled by (28), the first. 2nd, 3rd. 4th. 5th tank (11) (12) (13)
(14) The gas from (15) goes to the first main pipe (29),
No gas from the 6th tank (16) goes to the 2nd main pipe (30)
sent to. Note that (31) and (32) are stop valves.

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 suitably 50W to 3K11, and the frequency is suitably IMHZ to 10MH2. Inside the reaction tube (33) is a cylindrical film-forming substrate (35) made of aluminum or nickel. is the sample holding cylinder (36
), this holding stand (36) is driven to rotate by a motor (37), and the substrate (35) is heated to about 200 degrees by a suitable heating means.
It is heated uniformly to a temperature of from 400°C to 400°C, preferably from about 200°C to 350°C. Furthermore, the inside of the reaction tube (33) is a-
A high degree of vacuum condition (discharge voltage 0.1 to 2
．． By requiring a rotary pump (0 Torr)
38) and a diffusion pump (39).

In the glow discharge decomposition device configured as above,
For example, an a-3iC film (containing P) is used as a substrate (35).
1. Second. Third. Fifth regulating valve (
17) (1B) (19) Open (21) and release 5IHn+CJz, PH+, and Hz gases from each. The amount of release is determined by the mass flow controller (23) (24)
(25) Controlled by (27), 5l) It+C
The mixed gas of Jz+PHi+H1 is flowed into the reaction tube (33) via the first main pipe (29). Then, the inside of 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, and the high frequency power of the capacitive discharge electrode (34) is 50% to 3%1. , or in conjunction with the frequency being set to 1 to 10 MH2, glow discharge occurs, the gas decomposes, and an a-SiC film containing P 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-3iC layer is produced on an aluminum deposition substrate, and its C,)! The conductivity was measured with respect to the gas mixture ratio.

That is, using the capacitively coupled glow discharge decomposition device shown in FIG.
At a flow rate of secn+, H2 gas is released from the fifth tank (15) at a flow rate of 300sec, and then the second tank (12)
CzHz gas is released at a flow rate of 10 to 100 scca+, and a-
When a SiC film was manufactured and its dark conductivity and photoconductivity were measured, the results shown in FIG. 26 were obtained. still,
The manufacturing conditions are a substrate temperature of 300°C and a gas pressure of 0.45.
Torr and high frequency power were set to 150W.

According to FIG. 26, the horizontal axis represents the CtHz gas flow rate (scca
+), the vertical axis represents the conductivity [(Ω・cm)-'),
- The mark is a plot of dark conductivity, the mark O is a plot of photoconductivity, and a and b are respective characteristic curves.

As is clear from Fig. 26, the dark conductivity is 10-” (Ω・
cm)-' or more, with a maximum of 10-'' (Ω・c
m)-' or higher was obtained. Furthermore, the photoconductivity was 1000 times or more as compared to the dark conductivity, which indicates that this a-SiC layer has photoconductivity that is sufficiently satisfactory for use in electrophotographic photoreceptors.

(Example 2) In this example, based on (Example 1), PH3 gas (or B
When dark conductivity and photoconductivity were measured by introducing AH, gas), the results shown in FIG. 27 were obtained.

In the figure, the horizontal axis is P for the total flow rate of 5iHa and CzHt.
) Iff pure quantity (this is the absolute flow rate of PH calculated from the dilution ratio of H2 gas). In addition, a case where the pure amount of Pl (3) is replaced with the pure amount of B, H, is also described as a reference example.

According to FIG. 27, the mark is a plot of dark conductivity,
The circle 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 SiC layer has satisfactory photoconductivity for use in electrophotographic photoreceptors.

(Example 3) In this example, (Example 1) medium CzHz gas flow rate is 101
The spectral sensitivity characteristics of the a-SiC layer obtained with the setting of 05e were measured, and the results were the spectral sensitivity characteristics 'RIAe' 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 1010
A-SiC layer obtained by setting 5e (thickness 30.cz
The characteristics of surface potential, dark decay, and light decay were measured for m). This measurement was performed by negatively charging the surface with a -5,6 KV corona charger, and measuring the change in surface potential over time in the dark and the
This figure follows the change in surface potential over time immediately after irradiation with 50 nm monochromatic light.

The results are shown in FIG. 29, where flg 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 -530V, and the dark decay is about 30% 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-SiC layer obtained in (Example 4) was heated to +5.6KV.
When positively charged with a corona charger, the surface potential was several tens of volts.

And a-3iC manufactured based on this (Example 4)
The layered photoreceptor was negatively charged with a -5.6KV corona charger, and then imagewise exposed to perform a magnetic brush phenomenon. As a result, a high-quality image with high image density and contrast was obtained, and it was repeated 200,000 times. Even after repeated tests, 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. ) from the third tank (
PH3 gas from 13) and H2 from the fifth tank (15)
Gas and NO gas were released from the sixth tank (16), respectively, and the first layer 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.
, charged to negative polarity with a corona charger connected to a high voltage source of 6KV, and then subjected to monochromatic light (650nm)
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...-720V Photosensitivity...0.53cIl! erg-1 residual potential...
-30V (Example 6) In this example, the photoreceptor of the first embodiment was manufactured in the same manner as in (Example 4).

The manufacturing conditions were as shown in Table 2, and the electrophotographic properties were as follows.

Surface potential...-680V Photosensitivity...0.63cIII2erg-1 residual amount
...3ov (Example 7) In this example, a photoreceptor of the second embodiment was manufactured under the conditions shown in Table 3, and the following electrophotographic characteristics were obtained.

Surface potential...-720V Photosensitivity...0.65CIl! erg-' residual potential...
-25V (Example 8) In this example, a photoreceptor of the third embodiment was manufactured under the conditions shown in Table 4, and the following electrophotographic characteristics were obtained.

Surface potential: -790 ■ Photosensitivity: 0.65 cfflzerg-I residual potential:
...30V In addition, when the surface potential, dark decay, and light decay characteristics of this photoreceptor were measured in the same manner as in (Example 4), the 30th
The results shown in the figure were obtained. In the figure, h and i are a dark decay curve and a light decay curve, respectively.

As is clear from FIG. 30, the surface potential is significantly large at approximately -790V, and the dark decay is approximately 24χ after 5 seconds, indicating excellent charge retention ability.

(Example 9) In this example, a photoreceptor of the fourth embodiment was manufactured under the conditions shown in Table 5, and the following electrophotographic characteristics were obtained.

Surface potential...-830v Photosensitivity...0.63cm"erg-heavy residual potential...
40V (Example 10) 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.

Nezukajoka RF power...150W Gas pressure...0.45Torr Substrate temperature...300℃ 5in4 gas flow rate...100sccIllH2 gas flow rate...300sccrn The ○ marks 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 CJz gas increases, the film formation rate increases, and the rate is approximately 5%.
The film formation rate was ~13 μl.

(Example 11) In this example, the hydrogen content in the film was tracked while changing the content ratio of czoz gas under the same manufacturing conditions as in (Example 10), and the results shown in Figure 32 were obtained. .

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

As is clear from Fig. 32, as the content ratio of C and Ht gases becomes thicker, the number of C-H bonds increases and the S-
It can be seen that H-bonds are reduced.

〔Effect of the invention〕

As described above, according to the method for manufacturing an electrophotographic photoreceptor of the present invention,
Since a-SiC, 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 protection layer and a carrier injection blocking layer. As a result, an electrophotographic photoreceptor consisting only of a photoconductive a-5iC layer could be provided.

Further, according to the manufacturing method of the present invention, when glow discharge decomposition is performed using a combination of cznz gas and St-containing gas, a significantly high film formation rate can be obtained, thereby improving manufacturing efficiency and manufacturing cost.

Furthermore, according to the manufacturing method of the present invention, by changing the content of carbon and Va 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. .

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, there is provided an electrophotographic photoreceptor for negative polarity that can be charged advantageously to negative polarity.

Furthermore, when the conventional a-3i photoreceptor is used for a long period of time, local discharge damage on the photoreceptor surface is likely to occur due to corona discharge, and this causes spots to appear on the image. However, according to the manufacturing method of the present invention, a
-St has a dielectric constant of ε=12, while a-SiC
is about half that of ε・7, so it has excellent charging ability, and as a result, the above-mentioned discharge breakdown does not occur even if the surface potential is high (and as a result, high quality and high reliability are achieved. An electrophotographic 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 photoreceptor is deteriorated due to filming, etc., even if the deteriorated surface is repeatedly polished and regenerated with an abrasive, etc., the initial characteristics of the photoreceptor are maintained without being limited in the amount of polishing. 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 the conventional A-5T photoreceptor, the problem with the A-5I photoreceptor is that it is inferior in moisture resistance and tends to cause image blurring. 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-Si 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.

In addition, compared to the a-3i 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, if necessary, doping with an impurity element has the advantage that deterioration on the long wavelength side is also possible.

[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. FIGS. 4, 5, 6, 7, 8, and 9 are explanatory diagrams showing 71 areas of the photoreceptor according to the first embodiment of the present invention, respectively. An explanatory diagram showing the carbon content, FIG. 10 is an explanatory diagram showing the layer region of the photoreceptor of the second embodiment according to the present invention,
FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15, and FIG. 16 are explanatory diagrams showing the carbon content of the photoreceptor of the second embodiment according to the present invention, respectively, and FIG. Explanatory diagrams showing the layer regions of the photoreceptor of the third aspect of the invention, FIGS. 18, 19, 20, and 21 respectively show the carbon content of the photoreceptor of the third aspect of the invention. Explanatory diagram showing, 22nd
23 and 24 are explanatory diagrams showing the layer regions of the photoreceptor according to the fourth embodiment of the present invention, and FIGS. Fig. 25 is an explanatory diagram of a capacitively coupled glow discharge decomposition device used in the embodiment of the present invention, Fig. 26 is a diagram showing conductivity versus flow rate ratio of C2H and gas, and Fig. 27 is a diagram showing PH, gas, and BzHb gas. 28 is a diagram showing the spectral sensitivity characteristics of the amorphous silicon carbide layer. FIG. 29 is a diagram showing the dark attenuation and light attenuation of the amorphous silicon carbide layer. Fig. 30 is a diagram showing the dark decay and optical decay of the amorphous silicon carbide layer of the third embodiment, Fig. 31 is a diagram showing the film formation rate with respect to the flow rate ratio of C2H and gas, and Fig. 32 is a diagram showing CzHz.
FIG. 3 is a diagram showing the bonding ratio of hydrogen atoms to the gas flow rate ratio. 1...Substrate 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 manufacturing an electrophotographic photoreceptor in which a photoconductive amorphous silicon carbide layer that can be charged to a negative polarity is formed on a substrate by glow discharge decomposition of an amorphous silicon carbide generating gas, the gas being 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, 0 to 1 mol% of a gas containing Group Va elements of the periodic table is added to the amorphous silicon carbide generating gas. and an electrophotographic photosensitive method characterized in that when forming the first layer region, the proportion of the gas containing Group Va elements of the periodic table in the amorphous silicon carbide generating gas is larger than when forming the second layer region. How the body is made. (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.