JPS63108349A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance dark resistivity and photosensitivity of a photosensitive body in the near infrared region by incorporating Ge and a specified amount of an element of group Va of the periodic table in an amorphous silicon carbide layer. CONSTITUTION:The layer 5a made of amorphous silicon carbide (a-SiC) is formed on a substrate 1, and it is composed of a layer region 6a containing Ge uniformly or not uniformly in the layer thickness direction and the element of group Va, preferably, more than a layer region 7a, and the layer region 7a containing said element in an amount of 0-10,000ppm. C is contained uniformly in both layer regions, or more in either layer regions than the other, thus permitting the obtained photosensitive body to be enhanced in dark resistivity and photosensitivity characteristics, both of a surface layer and a barrier layer to be made substantially unnecessary, and carrier generation efficiency to be also enhanced in the near infrared region.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor comprising a photoconductive amorphous silicon carbide layer, and particularly to an electrophotographic photoreceptor that can be charged to a negative polarity.

[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-3i) layer only has a dark resistivity of about 109 Ωcm unless it is doped with any impurity element, and when used in an electrophotographic photoreceptor. To achieve this, it is necessary to increase the charge retention ability by increasing the dark resistivity to 10I2Ω·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.

In addition, high resistance can be expected by adding boron, etc., but a sufficiently satisfactory dark resistivity cannot be obtained and the IQI
It is only about IΩ・CII+.

On the other hand, along with the development of doping agents as mentioned above, a-5i
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-5t photoconductive layer (3) and a surface protection layer (4) are sequentially laminated thereon.

According to this laminated light body, the carrier injection blocking layer (2) prevents injection of carriers from the substrate (1), and provides surface protection J! 1(4) protects the a-Si photoconductive N(3) and improves moisture resistance, etc., but both layers (
The purpose of both 2) and (4) is to increase the dark resistivity of the photoreceptor to increase the charging ability, and for this purpose, it is not necessary to make these layers photoconductive.

As described above, the conventionally well-known a-Si electrophotographic photoreceptor has a major feature in that the photocarrier generation layer is formed of an a-Si photoconductive layer, and as a result, it has excellent heat resistance, durability, and photosensitivity characteristics. However, since the dark resistivity is insufficient, the dark resistivity is increased by using doping agents or by making the photoreceptor a laminated type. That is, carrier injection prevention 3I (2
) and the surface protective layer (4) complement the defects of the a-5i photoconductive layer itself, and the a-9t photoconductive layer (3)
- can be said to be a group that can be distinguished from the actual purchasers.

In view of the above circumstances, the present inventors have already discovered that amorphous silicon carbide (hereinafter abbreviated as a-3iC) has photoconductivity and has a dark resistivity of 1013 Ω·co+ or more regardless of the presence or absence of a doping agent. Furthermore, they have found that by selecting a doping agent, it is possible to obtain an electrophotographic photoreceptor that can be charged to a negative polarity.

The reason why the above a-SiC75 could be used as an electrophotographic photoreceptor is that its layer has a high carrier mobility, and also 1G-"
This is because the dark conductivity was less than (Ω·cm)−′, and a large charging ability was thereby obtained.

However, a-
Even with a 3iC photoconductor, satisfactory electrophotographic properties have not yet been obtained depending on the wavelength of the light source.For example, if a light source that can emit light at long wavelengths is used, The photosensitivity characteristics are still not fully satisfactory compared to a-5iCli, and there is a problem that carrier generation efficiency is reduced due to insufficient absorption by a-SiC@.

In addition, with the development of laser beam printers capable of high-speed printing, compact and highly reliable semiconductor lasers have come to be used as laser light sources, but on the other hand, the oscillation wavelength of this laser light has shifted to near infrared. Because of this, the above-mentioned problems tend to occur.Furthermore, when this laser light is projected, the light that reaches the substrate is reflected, which tends to cause interference fringes in the image.

[Purpose of the invention]

The present invention was devised in view of the problem of ridges, and its purpose is to substantially eliminate the need for a surface protection layer and a carrier injection blocking layer, to make the entire layer made of photoconductive a-SiC, and to provide a long structure. An object of the present invention is to provide an electrophotographic photoreceptor suitable for a semiconductor laser beam printer by increasing the photosensitivity characteristic on the wavelength side.

A second object of the present invention is to provide an electrophotographic photoreceptor in which interference fringes do not occur in images. Another object of the present invention is to provide an electrophotographic photoreceptor that can be negatively charged.

[Means for solving problems]

According to the present invention, germanium and 0 to 10
．． An electrophotographic photoreceptor capable of being charged to a negative polarity is provided, which is characterized by forming a photoconductive a-5iCFi containing a group Va element of the periodic table of 0OOppn+.

The present invention will be explained in detail below.

The electrophotographic photoreceptor of the present invention is characterized in that the photoconductive a-5iC layer contains germium, and the photoconductive a-5iC layer contains a Va group element to provide negative polarity. As already proposed by the present inventors, it can be a photoreceptor charged to .

That is, according to FIG. 1, a photoconductive a-3tC layer (5) is formed on a conductive substrate (1) by, for example, a glow discharge decomposition method, and carbon and Va are formed over the thickness direction of this layer.
Each group element is contained in the same content ratio. It was discovered that this resulted in a dark resistivity of 10'3 Ω・cm or more, which was also 1000 times higher than the bright resistivity. The a-5i is practical enough with just the layers.
The fact that it became a C photoreceptor was an unexpected result.

Furthermore, when the present inventors charged this a-SiC photoreceptor to positive or negative polarity and compared the charging performance of the two, the Va group element was added to this a-5iCN (5) at a concentration of 0 to 10.000.
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.

The reason why doping with Va group elements makes it easier to be negatively charged has not yet been elucidated and is still in the realm of speculation, but it is clear that the a-SiC layer is not sufficiently charged to retain negative charges. This is thought to be due to the fact that it has high resistivity, is excellent 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 N, P, ^s, sb,
Among them, P is preferable because it has excellent covalent bonding properties and can sensitively change semiconductor characteristics.

The reason why the a-3iCjig of the present invention has photoconductivity is that amorphous silicon and carbon are essential constituent elements, and hydrogen element (H) and halogen element are further added to terminate the dangling bonds. It is thought that photoconductivity is produced by containing carbon within the required range.The present inventors conducted experiments to confirm the presence or absence of photoconductivity by varying the content ratio of carbon, and found that a. -SiCM (5) preferably contains carbon in the range of 1 to 90 atoms χ, preferably 5 to 50 atoms χ,
Alternatively, the carbon content may be varied within this range over the layer thickness direction.

Further, the content of hydrogen element (H) and halogen element is 5 to 50 atoms χ, preferably 5 to 40 atoms χ, optimally 10
It is preferable to have χ to 30 atoms, and H element is usually used.

According to the present invention, the feature is that the photoconductive a-3iC layer as described above contains Ge element, which increases the photosensitivity on the long wavelength side, and as a result, it is suitable for semiconductor laser beam printers. A long wavelength light source can be used. Furthermore, even if a semiconductor laser is used as a light source, the amount of light reaching the substrate is significantly reduced or completely eliminated, thereby eliminating light reflected from the substrate and preventing the occurrence of interference fringes in the image.

For such an a-SiC layer, Ge may be contained throughout the layer thickness direction, or Ge may be locally unevenly distributed, but based on repeated experiments conducted by the present inventors, For example, in the region containing Ge, the content ratio of Ge to St may be set within a predetermined range.

That is, in this a-SiC layer, the atomic composition ratio of Si and Ge is l.
=1 to 19:1, preferably within the range of 2:1 to 10:1, and thereby the photosensitivity characteristics for semiconductor laser light having an oscillation wavelength of about 780 nm are significantly improved.

Furthermore, according to the present invention, fluorine (F) may be used as the element for terminating dangling bonds, and this F is
-' to 25 atoms χ, preferably 5X10-' to 10 atoms 2, stabilizes the atomic structure and improves durability and heat resistance.

When F is included in the element for terminating dangling bonds, the dangling bond is normally terminated with H since SiH, C, H, or other H-containing gas is used as the a-3iC generation gas. Compared to other monovalent elements, this H is easily incorporated into the terminals of dangling bonds, so it reduces the localized level density in the band gap, thereby increasing the doping efficiency of impurity elements and controlling valence electrons. This is desirable because it makes it easier.

When F is contained in this way, H tends to be contained incidentally, but when F and H coexist, St and HSGe
The bonding state between and H or C and H becomes more stable, thereby further improving the doping efficiency of the impurity element and the control of valence electrons.

When H and F are contained together, their total content is 5 to 50 atoms χ, preferably 5 to 40 atoms χ, optimally 10 to 30 atoms 2, and 5 at%%.
If it is less than that, dangling bonds cannot be sufficiently terminated, and the charging ability and photosensitivity characteristics decrease.
If it exceeds 50 atoms χ, the chain structure of Si, C or Ge increases, the film structure becomes less dense, defects occur and the photosensitivity decreases.

The thickness of the photoconductive a-5iCN (5) as described above should be at least 5 μm or more, so that the surface potential is 1200 V or more, and the upper limit is set as appropriate within the range of image resolution and image blurring. According to experiments conducted by the present inventors, the thickness is 5 to 100 μm, preferably 1 μm.
It is preferable to set it within the range of 0 to 50μ.

Furthermore, when the dark decay curve and light decay curve of this a-5iC layer were determined, it was confirmed that it had a high surface potential, excellent photosensitivity characteristics, and a small residual potential.

Thus, Nw has a single composition of photoconductivity a-S in one direction.
The iC layer alone is sufficient for practical use as a photoreceptor for semiconductor laser beam printers, and when F is further added, the electrophotographic photoreceptor becomes highly durable and highly heat resistant.

Therefore, based on the above results, the present inventors made further efforts in research, and found that various compounds were found inside this single composition layer.
1! It has been found that the electrophotographic properties can be further improved by creating a fin region.

That is, according to the present invention, the content ratio of the constituent elements is changed over the layer thickness direction, thereby continuously changing the content ratio, or creating a plurality of N regions, and correspondingly, the following Electrophotographic photoreceptors of the first aspect and the second aspect are obtained.

Hereinafter, various aspects of the electrophotographic photoreceptor according to the present invention will be explained in detail.

According to a first aspect of the present invention, there is provided an electrophotographic photoreceptor in which a photoconductive a-3iC layer is formed on a substrate, wherein the a-3iCN has at least a first layer region and a second layer region. The first (1) I region is disposed on the substrate side of the second WA layer region and contains Ge, and the second layer region has a
Provided is an electrophotographic photoreceptor that can be charged to a negative polarity and is characterized in that it contains 0 pp- of a Va group element.

According to this first aspect, at least the first JBI region and the second This is to generate N areas, and this aspect will be explained with reference to FIG. 3 and FIGS. 5 to 12.

In FIG. 3, a first layer region (6) is formed on a conductive substrate (1).
a) and a second layer region (7a) are formed in sequence, and both layer regions consist of an integrated photoconductive a-5iC layer (5a), and these layer regions are composed of Si and C-. Composition ratio, S
Although it is determined by changing the composition ratio of i and Ge, the content of Va group elements, etc., according to this embodiment, the first
! It is important that the region (6a) contains Ge, and the second Ng region (7a) contains O to 110,000 pp of Va group elements.

The second layer region (7a) has a Va group element content of 0 to 1.
Within the range of 10,000 pp, preferably 0 to 11,000
It is suitably controlled within the range of pp, and as a result, it is charged to a negative polarity and required electrophotographic properties such as surface potential and photosensitivity properties are obtained. When the first layer region (6a) containing more Va group elements than this N'pM region is formed, the conductivity increases in the substrate side region of the photoconductive a-SiC layer (5a), This prevents carrier injection from the substrate side and allows photocarriers generated in the entire area of the a-5iC layer to smoothly flow toward the substrate side, resulting in an increase in surface potential and improved photosensitivity characteristics. It is desirable in that sense.

When the first layer region (6a) contains Ge, light in the long wavelength region that is not absorbed in the second layer region (7a) is absorbed, thereby further increasing the photosensitivity.

Regarding this Ge content, the atomic composition ratio of Si and Ge is 1:1 to 19:1. It is preferable to set the ratio within the range of 2:1 to 10:1, thereby significantly improving the photosensitivity to semiconductor laser light having an oscillation wavelength of about 780 nm.

Further, the generation of the first layer region significantly reduces the amount of light reaching the substrate relative to the laser light source, thereby eliminating reflected light from the substrate and eliminating interference fringes in the image.

Further, this first N fil region (6a) has photoconductivity over its entire region, thereby preventing carrier injection of the conventional A-5T electrophotographic photoreceptor shown in FIG. It can be distinguished from (2).

Furthermore, according to the conventional a-Si electrophotographic photoreceptor, the layer thickness of the carrier injection blocking layer 11 (2) is set to be 115 times or less that of the a-Si photoconductive layer M (3). According to the electrophotographic photoreceptor of the present invention, the first layer region (6
Even if the layer thickness of a) is less than 1 times that of the second N region (7a), the residual potential can be sufficiently reduced and the photosensitivity characteristics can be improved, and the preferred layer thickness ratio is 1. It is best to set it to /2 or less, and optimally to 1/4 or less.

According to this first aspect, Ge is present in the first N region (6a).
When it is contained, it may be contained at a uniform content ratio over the layer thickness direction, or it may be contained at a non-uniform content ratio as shown in FIGS. 5 and 6.

In these figures, the horizontal axis represents the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis represents the Ge content. In addition, on this horizontal axis, the respective ranges shown in (6a) and (7a) represent the first layer region and the second layer region.

According to FIGS. 5 and 6, no step in the content ratio is created at the interface between the first layer region (6a) and the second layer region (7a), so that carriers are no longer trapped at the interface and remain. The potential becomes smaller.

Further, the carbon content may be set as shown in FIGS. 7 to 12. In these figures, the horizontal axis represents the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis represents the carbon content. Note that the ranges shown in (6a) and (7a) on this horizontal axis represent the first NTd region and the second layer region.

In Fig. 7, the carbon content ratio is constant throughout the entire layer, or in Fig. 8, the carbon content is reduced in the first layer region, whereas in Figs. This 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. 10 to 12, the surface potential and photosensitivity are further increased and the residual potential is reduced.

Thus, according to the photoreceptor of the first aspect, the carrier generation efficiency is higher over a wide wavelength range than that of the single composition a-SiC layer (5) shown in FIG. He's even better in the outside world.

According to a second aspect of the invention, there is provided an electrophotographic photoreceptor in which a photoconductive a-SiC layer is formed on a substrate, wherein the a-SiC layer covers at least a first layer region and a second layer region. the first N region is disposed closer to the substrate than the second N region, and the first N region is arranged closer to the substrate than the second N region;
Provided is an electrophotographic photoreceptor capable of being charged to a negative polarity, which contains a Va group element of 10,000 ppn+ and also contains Ge in the second layer region.

According to this second aspect, by changing the atomic composition ratio in the layer thickness direction with respect to the photoconductive a-5iC layer having a single composition shown in FIG.
This method will be explained with reference to FIG. 4 and FIGS. 13 to 20.

In FIG. 4, a first layer region (
6b) and a second layer region (7b) are sequentially formed, and the N regions of both layers are integrated into a photowind-resistant a-SiC layer (5b), and these layer regions have a composition ratio of St and C. , Si
According to this embodiment, the first layer region (6b) contains 0 to 110,000 pp of Va group elements, and the second layer region (6b) is determined by changing the composition ratio of Ge and the Va group element content. It is important that the Nw4 region (7b) contains Ge.

That is, the first layer region (6b) has a Va group element content of 0.
Within the range of 110,000 pp, preferably 0 to 10
00 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.

When Ge is contained in the second layer region (7b), the spectral sensitivity characteristics shift to the longer wavelength side, and the photosensitivity in that wavelength region becomes higher. Therefore, the Ge content should be set so that the atomic composition ratio of Si and Ge is within the range of 1:1 to 19:1, preferably 2:1 to 10:1. The photosensitivity to laser light is significantly improved.

When Ge is contained in this second NTi1 region (7b), it may be contained at a uniform content ratio over the layer thickness direction, or it may be contained at a non-uniform content ratio as shown in Figs. 13 and 14. In these figures, the horizontal axis indicates the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis indicates the Ge content. In addition, each range shown in (6b) and (7b) on the horizontal axis is the first W! It represents the J area and the second layer area.

According to FIGS. 13 and 14, the first ON region (6b)
No difference in content ratio is created at the interface between the first and second layer regions (7b), and as a result, carriers are no longer trapped and the residual potential is reduced.

According to this second aspect, the carbon content may be set as shown in FIGS. 15 to 20. In these figures, the horizontal axis represents the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis represents the carbon content. Furthermore, on this horizontal axis, (
The respective ranges shown in 6b) and (7b) represent the first layer region and the second layer region.

According to FIG. 15, the carbon content ratio is constant throughout the entire layer, or in FIG. 16, the carbon content is reduced in the second layer region, whereas in FIGS. 2
Figure 0 shows that the second layer region contains more carbon than the first layer region, which further increases the surface potential and improves the photosensitivity. Further, if the carbon content is gradually changed in the layer thickness direction as shown in FIGS. 18 to 26, the surface potential and photosensitivity are further increased and the residual potential is reduced.

Further, according to the second aspect, the second layer region (6b) is
It itself has a high resistivity, which makes the substrate (
There is an advantage that a large surface potential can be obtained without intervening another layer for blocking carrier injection from the substrate (1) between the substrate (1) and the first layer region (6b).

According to the photoreceptor of the second aspect obtained in this way,
The surface potential can be advantageously improved compared to the single composition a-3iC layer (5) shown in FIG.

Thus, according to the first aspect and the second aspect, the spectral sensitivity peak is shifted to the longer wavelength side, and the photosensitivity, surface potential, etc. are improved compared to the single composition a-5iC photoreceptor shown in FIG. An improved electrophotographic photoreceptor is provided.

Further, according to the present invention, 0.01 to 60 atoms χ, preferably 0.
．． The content is preferably in the range of 1 to 30 atoms χ, which improves the adhesion of a-SiCFi to the substrate.

Furthermore, according to the present invention, the single composition a-SiCFi and the a-3iCN of the first and second embodiments are both composed of photoconductive a-3iClii, thereby providing sufficient practical electrophotographic properties. are obtained, but these a-Si
A conventionally known surface protective layer may be formed on the surface of the C layer.

Various materials can be used for this surface protective layer as long as they themselves have high insulation properties, high corrosion resistance, and high hardness characteristics, such as organic materials such as polyimide resin, a-3
iC+ 5iOz, SiO+ Al zest stc
, Si3N+, a-3i, a-St:H, a-5
Inorganic materials such as i:F, a-SiC:H, and a-5iC:F can be used.

Furthermore, F may be contained in the first aspect and the second aspect as required.

That is, in the first layer region (6a) described in the first embodiment, 5
It is sufficient to contain F of X10-' to 25 atoms χ, preferably 5 Xl0-' to 10 atoms χ, thereby providing high durability and high heat resistance.

Further, in the second layer region (7b) described in the second embodiment, 5
×10-% to 25 atoms 2, preferably 5 × 10-% to 10 atoms χ of F may be included, which increases the photocarrier generation efficiency and improves the photosensitivity, and further improves the film itself. The durability and heat resistance of the material are improved, particularly against corona discharge, and the moisture resistance is improved.

Next, a method for manufacturing the electrophotographic photoreceptor of the present invention will be described.

In forming the a-3iC layer according to the present invention, thin film production techniques such as glow discharge decomposition method, ion blating method, reactive sputtering method, vacuum evaporation method, and CVD method can be used, and The raw material may be solid, liquid, or gas.

Hereinafter, an example in which the electrophotographic photoreceptor of the present invention is manufactured by a glow discharge decomposition method will be explained.

The a-SiC generating gas contains a Si-containing gas and a C-containing gas, and if necessary, (2) contains an inert gas (He, Ar, etc.) as a carrier gas. This Si-containing gas includes 5tH4, 5iJth+SsJ++, etc., and the C-containing gas includes CHt, CJh, CJ4. CJ□C
3H5, etc., or St (
CH3) a gas' etc. may be used.

When the a-5iC generation gas contains Ge, a Ge-containing gas may be introduced into the gas (Ge-containing gases include GeHa, Ge2H6, GeJs, etc.).

Furthermore, the ratio of Ge-containing gas in the a-3iC generation gas is related to the type of gas, but the ratio of Si-containing gas to Ge-containing gas is 1:1 to 30:1, preferably 2:1 to 15:1. It is best to set it within the range.

In addition, 0 to 10.000 of Va group elements are added to the a-SiC layer.
In order to make the content within the range of pp-, the a-5iC generation gas may contain 0 to 1 mol χ, preferably O to 0.1 mol χ, of the Va group element-containing gas; For gas! b, NHs, PHs, ^'iPs+5b
There is 83 mag.

When F is further contained in such a-3iC generation gas, it may be bonded to the Si-containing gas or C-containing gas as a monovalent element, for example, SiFa, SiHF.
31SiHzFz, 5iHJ, Cl3F, C)1
2Fz, CHF3. There is CF4. Also, this a-5i
F may be mixed into the C generation gas or the glow discharge region as an impurity or unavoidably, thereby causing F to be included in the film forming process. For example, IP is used as a cleaning agent for reaction vessels for glow discharge decomposition, but it remains and a-SiC
Ii! May be mixed during production.

In manufacturing the electrophotographic photoreceptor of the present invention, Si-containing gas and acetylene (C
It is desirable to form a-SiC using a mixed gas of Jt) gas, since it is possible to achieve a significantly high rate of film formation.

According to experiments repeatedly conducted by the present inventors, various St-based gases mentioned above can be used as the Si-containing gas. Got the speed. Incidentally, when an a-SiC film is produced using SiH* gas and CH4 gas, the film formation rate is about 0.3 to 1 μm/hour.

Furthermore, according to the manufacturing method of the present invention, when introducing the CJz and Si-containing gas into the glow discharge region, the gas composition ratio is within the range of 0.01:1 to 3:1, preferably 0.0.
5:1 to 1:11 optimally 0.05:1 to 0.3:
If the ratio is outside the 0.01:1 ratio, the dark resistivity will be less than 101Ω・cow, and the charge retention will not be sufficient, making it difficult to obtain a large charged potential. If the ratio is deviated from 3:1, the number of dangling bonds in the film increases and the dark resistivity decreases to 10”Ω.
・C11 or less.

According to the manufacturing method of the present invention, when producing the a-3iC layer under the manufacturing conditions 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.

That is, the high frequency power should be set in the range of 0.05 to 0.5 W/cm''; if it is less than 0.05 W/cm, the film formation rate will be low; When the temperature exceeds IIz, the film quality deteriorates due to plasma damage and the carrier mobility decreases. In addition, the gas pressure is 0.1 to 2.0 Torr.
Just set it within the range of r<, 0. If it is less than ITorr, the film formation rate will be low; 2. If QTorr is exceeded, the discharge becomes unstable. Furthermore, the substrate temperature is a-St:
The temperature is preferably about 30 to 80° C. higher than that of the H film, preferably in the range of 200 to 400° C. If the substrate temperature is less than 200° C., network formation of Si and C is inhibited, and if it exceeds 400° C., hydrogen desorption becomes significant and the dark resistivity decreases.

Next, the manufacturing methods for the above-described first and second aspects of the electrophotographic photoreceptor of the present invention are listed below. In both manufacturing methods, C2H2 is used as the C-containing gas to increase the film formation rate.

According to the manufacturing method of the first aspect, a photoconductive a-Si that can be charged to a negative polarity is produced by glow discharge decomposition of an a-SiC generation gas.
A method for manufacturing an electrophotographic photoreceptor in which CN is formed on a substrate, wherein the gas is composed of C2H and Si-containing gas, and the gas composition ratio is changed during film formation to form a small amount (both first and second) in the a-SiC layer. layer region and a second N Sr1 region, the first
The N region is disposed closer to the substrate than the second layer region, and contains Ge in the a-SiC generation gas when forming the first N region, and contains Ge in the a-SiC generation gas when forming the second layer region. Provided is a method for producing an electrophotographic photoreceptor, characterized in that the electrophotographic photoreceptor contains 0 to 1 mole χ of a Va group element-containing gas.

According to the manufacturing method of the second aspect, the a-5iC generating gas is decomposed by glow discharge to produce a photoconductive a-5i that can be charged to a negative polarity.
A method for manufacturing an electrophotographic photoreceptor in which CN is formed on a substrate, wherein the gas is composed of CJlt and Si-containing gas, and the gas composition ratio is changed during film formation to inject at least a first N 914 into the a-3iC layer. a first layer region and a second layer region;
The layer region is disposed closer to the substrate than the second N region, and when forming the first layer region, the a-3iC generation gas is exposed to a concentration of 0 to 1.
mol χ of Va group element-containing gas and a second N
A method for manufacturing an electrophotographic photoreceptor is provided, which is characterized in that Ge is included in the a-3iC generation gas when forming the fiJl region.

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. 5th tank (8) (
9) (10) (11) (12) are each 5
iHa+CtHz+GeHa, PIIs (contains 33 ppm when diluted with H2 gas), and Hl are sealed, and h is also used as a carrier gas. These gases correspond to the first. Second. Third. 4th. 5th and 11th valve adjustment (13)
(14) (15) (16) It is released by opening (17), and its flow rate is controlled by the mass flow controller (1B) (19) (20) (21) (22). Second. Third. 4th ° 5th tank (8
) (9) (10) (11) The gas from (12) is sent to the main pipe (23). Note that (24) is a stop valve. The gas flowing through the main pipe (23) flows through the reaction pipe (25)
A capacitively coupled discharge electrode (26) is installed inside this reaction tube (25), and the high frequency power applied to it is 50 to 3 cm, and the frequency is I 0 reaction tube (25 MHz to 50 Hz is suitable)
) has a cylindrical film-forming substrate made of aluminum (
27) is placed on a sample holder (28), and this holder (28) is rotated by a motor (29), and the substrate (27) is heated appropriately. by means of about 200 to 400°C, preferably about 2
It is uniformly heated to a temperature of 00 to 350°C. Furthermore, the interior of the reaction tube (25) requires a high vacuum state (discharge voltage 0.1 to 2.0 Torr) during a-3iCli shadow formation, so a rotary pump (30) and a diffusion pump (31) are required.
is connected to.

In the glow discharge decomposition device configured as above,
For example, an a-3iC film (containing Ge) is deposited on a substrate (27
), when forming on the 1st. Second. Third. Open the 5th degree regulating valves (13), (14), (15), and (17) to release 5tf14+CJz+GeHn and Hz gases from each. Release amount is determined by mass flow controller (1B)
(19) (20) Controlled by (22) 5iH
t, CJz + GeH4, Hz mixed gas is in the main pipe (23)
and into the reaction tube (27). Then, the inside of the reaction tube (27) 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 (26) is 50 to 3H1 or the frequency is 1. Coupled with the fact that the frequency is set between 50 MHz and 50 MHz, glow discharge occurs, gas is decomposed, and an a-3iC film containing Ge is formed on the substrate at high speed.

〔Example〕

Next, the present invention will be explained in detail.

(Example 1) In this example, a photoconductive a-3iC layer is produced on an aluminum film-forming substrate, and the spectral sensitivity characteristics, surface potential,
Photosensitivity and residual potential were measured.

That is, using the capacitively coupled glow discharge decomposition device shown in FIG.
CtHz gas from the second tank (9) at a flow rate of ecm, GeH from the third tank (10) at a flow rate of 10105e.
a gas at a flow rate of 30 sccm, and PH2 gas from the fourth tank (11) at a flow rate of 40 sec+a from the fifth tank (11).
12) From ■2 gas is released at a flow rate of 200scc111, and a thickness of about 30 μm is formed based on the glow discharge decomposition method.
-3iC layer was fabricated and its electrophotographic properties were measured.
The spectral sensitivity was as shown in FIG. 22, and the other characteristics were as shown below. Regarding the spectral sensitivity, a-3i
A C film was manufactured with a thickness of 5 μm and used as a measurement sample.

According to FIG. 22, the spectral sensitivity characteristic shows the photoconductivity when irradiated with equal energy light at each wavelength, X is the spectral sensitivity characteristic curve of this example, and y is the comparative example.

As is clear from the spectral sensitivity characteristic curve shown in FIG. 22, the photosensitivity is significantly improved in the wavelength region of about 700 to 800 nn+. However, in this example, the third! P1 section valve (
3) was closed, other manufacturing conditions were set to the same, and the spectral sensitivity characteristics (curve y) were measured in the same manner. As a result, the photosensitivity characteristics were inferior in the near-infrared region.

Further, the surface potential was negatively charged with a corona charger of -5.6 KV, and the surface of the photoreceptor was then irradiated with spectroscopic monochromatic light (770 nm), whereby the following electrophotographic characteristics were obtained. Note that the residual potential is the value 5 seconds after the start of exposure.

Surface potential: -520V Photosensitivity: 0.20cIII2er 1 residual type: 30V Furthermore, the photoreceptor produced in this example was printed on a semiconductor laser beam printer (wavelength: 70nm). When printed at a printing speed of 20 sheets, 7 minutes), a high-quality image with high contrast and high resolution was obtained without any striped patterns.

(Example 2) In this example, a photoreceptor of the first embodiment was manufactured under the conditions shown in Table 1, and the following electrophotographic characteristics were obtained. Note that the characteristic evaluation test is the same as in (Example 1)1, and is common to all of the present examples.

Surface potential...-580v Photosensitivity...0.23cn+"erg-'Residual potential...
・35 V Also, the photoreceptor of this example can be used in a semiconductor laser beam printer (
When printed at a wavelength of 770 nm and a printing speed of 20 sheets/min, a high-quality image with high contrast and high resolution was obtained with no striped pattern at all.

Furthermore, in this example, when 5iFn gas was discharged into the reaction tube at a flow rate of 50 seconds when forming the first layer region (6a), the surface potential became even higher.

(Left below) (Example 3) In this example, a photoreceptor of the second embodiment was manufactured under the conditions shown in Table 2, and the following electrophotographic properties were obtained.

Surface potential...-650■ Photosensitivity...0.21cm"erg-'Residual potential...
35V/'C Also, when the photoreceptor of this example was installed in a printer in the same manner as in (Example 2) and printed, a high-quality image with high contrast and high resolution was obtained without any striped patterns. Ta.

Furthermore, in this example, when forming the second 0M region (7b), SiF4 gas was discharged into the reaction tube at a flow rate of 50 seconds, and the moisture resistance and durability were further improved.

(The following is a blank space) [Effects of the Invention] As described above, according to the electrophotographic photoreceptor of the present invention, a-5iC having a photoconductive device throughout the entire layer has a high dark resistivity, and also has excellent photosensitivity characteristics. Due to this superiority, it is possible to substantially eliminate the need for a surface layer and a carrier injection blocking layer, and as a result, an electrophotographic photoreceptor consisting only of a photoconductive a-3iC layer can be provided.

Further, according to the present invention, by including Ge, the photosensitivity characteristic on the long wavelength side can be increased, which makes it suitable for use in semiconductor laser beam printers, and furthermore, interference fringes do not occur in the image, and as a result, A high-performance and highly reliable electrophotographic photoreceptor can be provided as a photoreceptor for semiconductor laser beam printers.

Further, according to the electrophotographic photoreceptor of the present invention, by incorporating a predetermined amount of F into the film, it is possible to improve heat resistance and durability and maintain excellent initial photosensitivity. It can provide reliable electrophotographic characteristics. By changing the F content in the layer thickness direction, it is possible to increase the doping efficiency of the Va group element and improve carrier injection blocking ability, or to improve moisture resistance or environmental resistance.

Further, according to the electrophotographic photoreceptor of the present invention, by changing the contents of carbon and Va elements in the layer thickness direction, the surface potential can be improved, the photosensitivity characteristics can be increased, and the residual potential can be significantly reduced. Can be done. In particular, when the carbon content is varied in the layer thickness direction, the resistivity can be controlled and a desired metal region can be obtained, and as a result, an electrophotographic photoreceptor with significantly higher performance can be provided.

Further, according to the present invention, there is provided an electrophotographic photoreceptor for negative polarity that can be advantageously charged to negative polarity.

According to the electrophotographic photoreceptor of the present invention, since the electrophotographic photoreceptor itself has excellent charging ability and environmental resistance, there is no need to particularly provide a protective layer. When the surface has 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 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 (this causes spots on the image). However, according to the present invention, a-3i
The dielectric constant of a-5iC is ε=12, while the dielectric constant of a-5iC is ε=12.
7, it has excellent charging ability, and as a result, the above-mentioned discharge breakdown does not occur even if the surface potential is increased, and as a result, a high quality and highly reliable electrophotographic photoreceptor can be produced. is provided.

Furthermore, when the electrophotographic photoreceptor of the present invention is compared with the conventional A-3T photoreceptor, problems with this a-Si photoreceptor include poor moisture resistance, which often causes image deletion, and poor charging performance. Due to the poor performance, a ghost phenomenon occurs, but in order to solve this problem, a heater is used to heat the photoreceptor when using the a-5i5 photoreceptor, thereby preventing the occurrence of this phenomenon. On the other hand, the electrophotographic photoreceptor of the present invention has an advantage in that it is not necessary to use a heater as described above because it has excellent moisture resistance and charging ability.

Further, compared to the a-Si photoreceptor, the electrophotographic photoreceptor of the present invention can obtain a wide range of spectral sensitivity characteristics (peak 600 to 700 nm) and increase the photosensitivity itself by simply changing the carbon content. 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 the electrophotographic photoreceptor of the present invention, FIG. 2 is an explanatory diagram showing the layer structure of a conventional electrophotographic photoreceptor, and FIG. FIG. 4 is an explanatory diagram showing the layer regions of the photoconductor of the second embodiment of the present invention, and FIGS. 5 and 6 are germanium diagrams of the photoconductor of the first embodiment. Explanatory diagram showing the content, Fig. 7,
8, 9, 1O, 11 and 12 are explanatory diagrams showing the carbon content of the photoreceptor of the first embodiment, and FIGS. 13 and 14 are explanatory diagrams showing the carbon content of the photoreceptor of the second embodiment. Explanatory diagrams showing germanium content in the body, Figures 15, 16, 17, 1
8, 19, and 20 are explanatory diagrams showing the carbon content of the photoreceptor of the second embodiment, and FIG. 21 is an explanatory diagram of the capacitively coupled glow discharge decomposition device used in the embodiment of the present invention. Second
FIG. 2 is an explanatory diagram showing the spectral sensitivity characteristics of the photoreceptor of the present invention. 1...Substrates 5, 5a, 5b...Photoconductive amorphous silicon carbide layers 6a, 6b...First layer regions 7a, 7b...Second layer regions Patent Applicant (663) Kyocera Takao Kawamura, Dodo Co., Ltd.

Claims (1)

[Claims] An electrophotographic photoreceptor capable of being charged to a negative polarity, characterized in that a photoconductive amorphous silicon carbide layer containing germanium and 0 to 10,000 ppm of Group Va elements of the periodic table is formed on a substrate.