JPS63108348A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To dispense with the protective layer and the barrier layer of photosensitive body and to prevent ghost phenomenon by decomposing a gas mixture of He and a gas containing an element of group IIIa of the periodic table through glow discharge to form a photoconductive layer. CONSTITUTION:The gas for producing amorphous silicon carbide (a-SiC) is decomposed by glow discharge to form a positively chargeable photoconductive layer 5a made of a-SiC on a substrate 1. As said gas, a mixture of C2H2 and an Si-containing gas in a ratio of 0.01:1-3:1 further containing an element of group IIIa of the periodic table is used. The photoconductive layer 5a made of a-SiC composed of layer regions 6, 7 is formed on the conductive substrate 1. The layer region 7 is prepared by adding He to a gas mixture of C2H2 and the Si-containing gas in a ratio of <=5:1, and it contains the element of group IIIa in an amount of 10<-6>-1mol% and the layer region 6 contains said element more than the layer region 7. The content of C in the layer regions 6, 7 may be changed.

Description

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

[Prior art and its problems]

In recent years, progress in electrophotographic photoreceptors has been remarkable, and with the development of copying machines, 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, an amorphous silicon (hereinafter abbreviated as a-Si) layer can only have a dark resistivity of about 10 drops Ωcm unless it is doped with any impurity element, and is used in electrophotographic photoreceptors. In this case, 101tΩ・0111
It is necessary to increase the charge retention ability by increasing the dark resistivity. 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 resistivity cannot be obtained and is only about 101 Ω·cm.

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)
carrier injection blocking layer (2) on top of the a-3t photoconductive M
(3) and a surface protective layer (4) are sequentially laminated.

According to this laminated light body, the carrier injection blocking layer (2) blocks injection of carriers from the substrate (1), and the surface protection layer (4) blocks the a-3i photoconductive layer (3). It protects and improves moisture resistance etc., but both layers (2)
The purpose of both (4) and (4) is to increase the dark resistivity 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 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 11 (2) formed on the laminated photoreceptor
) and the surface protective layer (4) complement the defects of the a-5t photoconductive layer itself, and the a-3i photoconductive layer (3)
It can be said that it is a layer that can be practically distinguished.

In view of the above circumstances, the present inventors have already discovered that amorphous silicon carbide (hereinafter abbreviated as a-5iC) has photoconductivity and has a dark resistivity that easily exceeds IQIIΩ cm 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-3iC layer could be used as an electrophotographic photoreceptor is as follows.
The layer has a large carrier mobility, and even 10-'
This is because the dark conductivity was less than (Ω·cm)−′, and a large charging ability was obtained.

However, even with the a-3iC electrophotographic photoreceptor, which has such a high carrier mobility, satisfactory electrophotographic properties may still not be obtained depending on the wavelength of the light source.
For example, when a general light source such as a fluorescent lamp (with a spectrum shifted toward relatively short wavelengths) is used as a light source for static elimination, a ghost phenomenon (the previous image is completely distorted) due to the optical memory effect during image exposure. (a phenomenon in which the previous image remains without being removed and the previous image reappears as the next image is formed) tends to occur.

In order to solve this problem, it is effective to increase exposure by using a light source that emits long wavelength light as a light source for static elimination, and a light emitting diode array is a suitable light source for this purpose. However, when using this diode array, if strong exposure is applied to prevent the ghost phenomenon,
This causes problems such as a decrease in charging ability and an increase in dark decay. Furthermore, from the manufacturing cost perspective,
Light emitting diodes are much more expensive than fluorescent lamps, and a low-cost light source is desired.

[Purpose of the invention]

Therefore, the present invention was devised in view of the ridges, and its purpose is to substantially eliminate the need for a surface protective layer and a carrier injection blocking layer, to make the entire layer of photoconductive a-SiC, and An object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor that can prevent the occurrence of a ghost phenomenon.

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

[Means for solving problems]

According to the present invention, the gas is composed of acetylene and silicon-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and the gas composition ratio is set within the range of 0.01:1 to 3:1, and the gas composition ratio is set within the range of 0.01:1 to 3:1.
A-SiC generation gas containing a gas containing 101 to 1 mol χ of Group Ma elements of the periodic table (hereinafter abbreviated as Group IIIa elements) is decomposed by glow discharge onto the substrate. Provided is a method for producing an electrophotographic photoreceptor, which comprises forming an a-5iC layer that can be positively charged.

The present invention will be explained in detail below.

According to the production method of the present invention: H is added to the a-SiC generation gas.
Furthermore, when a photoconductive a-5iC layer is formed on a substrate from CzH gas and Si-containing gas by glow discharge decomposition method, a large dark resistivity can be obtained. Furthermore, as the present inventors have already proposed, if the a-5iC generation gas contains 10@4 to 1 mole .chi. of the a-group element gas, a photoreceptor that is favorably charged to positive polarity can be obtained.

That is, according to FIG. 1, a photoconductive a-5iC layer (5) is formed on a conductive substrate (1) by, for example, a glow discharge decomposition method, and carbon and ma
Each group element is contained in the same content ratio. It was discovered that this resulted in a dark resistivity of 1QI3Ω·cm or more, which was also 1000 times higher than the bright resistivity, and as is clear from the examples described below based on this knowledge,
A-5iC is sufficiently practical with just this single composition layer.
The fact that it became a 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, they found that the a-3iC layer (5) contained 0.1 to 10. 0
00pf111 range, preferably 0.1 to 1000p
It has also been found that doping within the range of p+a can advantageously increase the charging ability with positive polarity.

The reason why doping with l1la group elements makes it easier to be positively charged has not yet been elucidated and cannot be left out of the realm of speculation, but it appears that the a-5iC layer is sufficiently charged to retain positive charges. This is believed to be because it has high resistivity, is excellent in preventing injection of negative charges from the substrate, and has excellent charge mobility with respect to positive charges.

In addition, this I [[A group elements include B, A1. Ga, I
Among these, B is preferable because it has excellent covalent bonding properties and can sensitively change semiconductor properties.

When doping with the Ma group element as described above, it is preferable that the a-3iC generation gas contains 10-4 to 1 mol2, preferably 10-& to 0.1 mol χ of the l1Ia group element gas. , thereby making it possible to dope within the above-mentioned required range.

In addition, IhH is used when doping with a Ma group element.

, BPs, AI(CII+)s, Ga(CHs)z, I
n(CHs)s etc. are used.

The reason why the a-5iC layer of the present invention has photoconductivity is that amorphous silicon and carbon are essential constituent elements, and hydrogen element (H) and halogen are added to terminate the dangling bonds. It is believed that photoconductivity occurs when the elements are contained within the required range.The present inventors conducted experiments to confirm the presence or absence of photoconductivity by changing the content ratio of carbon in a number of ways. a
-5iC layer (5) preferably contains carbon in the range of 1 to 90 atoms χ, preferably 5 to 50 atoms χ, or the carbon content may be varied within this range in the layer thickness direction. Good too.

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 usually the element ▪ is used. Since this H element is easily incorporated into the terminal portion of the dangling bond, the localized level density in the band gap is reduced, thereby providing excellent semiconductor characteristics.

Further, a part of this H element may be replaced with a halogen element, thereby lowering the localized level density of the a-SiC layer and improving photoconductivity and heat resistance (temperature characteristics).

Its substitution ratio is 0.0 among all elements for dangling bond termination.
01 to 50 atoms χ, preferably 1 to 30 atoms χ. In addition, halogen elements include 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.

According to the production method of the present invention, C, H is added to the a-3iC generation gas.
, and contains less than 5 times, preferably 0.5 to 3 times as much He gas as the total flow rate of the Si-containing gas, which increases the ionization voltage during glow discharge decomposition and increases the excitation. The energy increases and thus the plasma temperature increases, so that this atmosphere favors the formation of a-5iCJiiJ, improving the film quality and eliminating the ghost phenomenon. Such a modification phenomenon of the a-3iC layer not only eliminates the ghost phenomenon, but also has an advantageous effect on overall electrophotographic characteristics such as photosensitivity and surface potential.

The thickness of the photoconductive a-SiC layer (5) as described above should be at least 5 μm or more, so that the surface potential becomes 1200 V or more, and the upper limit thereof is within the range where image resolution and image blurring do not occur. is appropriately selected, and according to the experiments of the present inventors, the ugliness is 5 to 100μ, preferably 1
It is preferable to set it within a range of 0 to 50771 m.

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

In addition, the present inventors have found that when manufacturing the above-mentioned electrophotographic photoreceptor, it is preferable to mix 02Hz gas and Si-containing gas at a predetermined ratio based on the glow discharge decomposition method. It is formed into a film and has photoconductivity.

That is, when introducing CzHz and Si-containing gas into the glow discharge region, the gas composition ratio is adjusted to 0.01:1 to 3:
l, preferably within the range of 0.05:l to l:1, optimally within the range of 0.05:1 to 0.3:1, and from a ratio of 0.01:1 to If it deviates from the ratio of 3:1, the dark resistivity will be less than 10+1 Ω・cm, and the charge retention capacity will be insufficient, making it impossible to obtain a large charged potential.If the ratio deviates from 3:1, dangling bonds in the film will occur. increases, and the dark resistivity becomes 10+1Ω−'c+s or less.

5IH41S1zH4,5iJ as the Si-containing gas
There are s+5iFa+SiC1m, 5iHC13, etc.
Particularly, 5il14+5iJi is desirable since St itself is bonded to H, so H is easily incorporated into the film, reducing dangling bonds in the film and improving photoconductivity.

In addition, when H is used as the element for terminating dangling bonds, H2 gas may be blended in an amount not more than three times, preferably not more than twice, the total flow rate of Ctlh gas and SiH# gas. If it comes off, hydrogen in the film becomes excessive and the electrical characteristics required of the photoreceptor deteriorate.

According to the manufacturing method of the present invention, when producing a-5iCN 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. .

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

Thus, the photoconductive a-5i of a single composition throughout the layer thickness direction
An electrophotographic photoreceptor that can be put into practical use with just the C layer is provided.

Therefore, based on the above results, the present inventors conducted further research and found that various N
It has been found that electrophotographic properties can be further improved by generating a fiJI region.

That is, in the manufacturing method of the present invention, the content ratio of carbon or the Ma group element as a constituent element is changed over the layer thickness direction,
As a result, a plurality of layer regions are generated, and the following methods of manufacturing an electrophotographic photoreceptor are obtained according to the number of N regions.

According to the present invention, in such an embodiment, from the substrate side to the photoreceptor surface side, the first layer region, the second layer region, and if necessary, the third layer region, and the fourth layer. a-S during formation of at least the second layer region and the third layer region.
It is characterized by containing lie in the iC generation gas, thereby eliminating the ghost phenomenon.

Hereinafter, the manufacturing method of the present invention will be described in detail regarding the first aspect and the second aspect, and the third aspect and the fourth aspect shall correspond thereto.

According to the first aspect, a method for manufacturing an electrophotographic photoreceptor in which a photoconductive a-SiC layer that can be positively charged is formed on a substrate by glow discharge decomposition of an a-5iC generation gas. The gas is composed of CzHz and Si-containing gas, the gas composition ratio is set within the range of 0.01:1 to 3:1, and while containing the Ma group element-containing gas, A method for manufacturing an electrophotographic photoreceptor is provided, which is characterized by reducing this content ratio.

That is, according to this first aspect, by incorporating a Ma group element into the photoconductive a-3iC layer having a single composition shown in FIG. This 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-SiC layer (5a); contains more Ma group elements than the second layer region (7), and also contains Il during a-SiC generation during the formation of the second N region ()).
It is important to contain a fixed amount of eHe gas.

The second layer region (7) has an rIia group element content of 0.1
It is appropriately controlled within the range of 10.000 ppm to 10.000 ppm, preferably within the range of 0.1 to 1.000 ppm, thereby positively charging and improving the required electrophotographic properties such as surface potential and photosensitivity characteristics. characteristics are obtained. And this N8m
The first layer region (6) containing more Ma group elements than the
When formed, the conductivity increases in the substrate side region of the photoconductive a-3iC layer (5a), which prevents injection of carriers from the substrate side and eliminates photocarriers generated in the entire region of the a-StC layer. flows smoothly to the substrate, and as a result,
As the surface potential increases, the photosensitivity characteristics improve.

Furthermore, in forming this second layer region (7), a-3
It is preferable to include He gas in the iC generation gas in an amount of 5 times or less, preferably 0.5 to 3 times the total flow rate of CJ* and Si-containing gas, thereby causing a ghost phenomenon. It disappears.

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

That is, the first layer region (6) improves the photosensitivity characteristics over the whole area due to the photoconductivity of the entire region. Especially the first
Excellent photosensitivity characteristics can be obtained for relatively long-wavelength light that easily reaches the layer region (6), and this makes it suitable for electrophotographic photoreceptors using semiconductor lasers as recording light sources.

Further, according to the conventional a-3i electrophotographic photoreceptor, m* of the carrier injection blocking N(2) is set to m* of the a-Si photoconductive layer (3).
), whereas according to the manufacturing method of the present invention, the layer thickness of the first layer region (6) has a photosensitivity characteristic lower than that of the second layer region (7). The layer thickness ratio is preferably set to 1/2 or less, most preferably 18 or less.

Furthermore, according to the first aspect, the amount of the carbon stand is adjusted from FIGS. 4 to 9.
In these figures, which may be configured as shown in the figures,
The horizontal axis shows the layer thickness from the substrate to the photoreceptor surface, and the vertical axis shows the carbon content. Furthermore, on this horizontal axis (6)
, 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 small in the first N region, whereas in FIGS. The figure shows that the first layer region contains more carbon than the second layer region, which further increases the surface potential and improves the photosensitivity characteristics. If the carbon content is gradually changed in the layer thickness direction as shown in FIGS. 9 to 9, the surface potential and photosensitivity will be further increased and the residual potential will be reduced.

According to a second aspect, a method for manufacturing an electrophotographic photoreceptor in which a photoconductive a-SiC layer that can be positively charged is formed on a substrate by glow discharge decomposition of an a-3iC generation gas. The gas is composed of CgH* and Si-containing gas, and the gas composition ratio is set within the range of 0.01=1 to 3:1, and the cznz content composition ratio is changed during film formation to achieve the a- The 3iC layer has a first region, a second LiI region, and a third region, and the first 1! region is closer to the substrate than the second layer region,
The second layer regions are each disposed closer to the substrate than the third layer regions, and the third layer regions contain more carbon than the second layer regions, and when the second layer regions are formed, the a-Si
The C-generating gas contains a gas containing 10-b to 1 mol χ of a group element, and when forming the first N fin region, a-
Provided is a method for manufacturing an electrophotographic photoreceptor, characterized in that the proportion of the Ma group element-containing gas in the 5iC generation gas is larger than that during the formation of the second layer region.

That is, according to this second aspect, as shown in FIG.
A third Ji 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 adjusted to the second layer region (7). (7) more than, 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-5iC layer (
5b).

When this third layer region (8) is formed, the a-3iC layer (
5b), the dark resistivity on the surface side becomes thicker, and the surface potential of the photoreceptor increases markedly.

That is, the third layer region (8) is a photoconductive a-3iC layer (5
It is formed to increase the resistance of the surface side of b),
This layer can be completely distinguished from the conventionally known surface protective layer (4) described in FIG. Furthermore, according to a functionally separated photoreceptor that is divided into a photocarrier generation layer and a carrier transport layer,
Although the carrier transport layer is made to have a high resistance of tQImΩ・cm or more, this layer is not required to have particularly high photoconductivity, and usually has a photoconductivity with a ratio of photoconductivity to dark conductivity of less than 1000 times. On the other hand, the third layer region (8) has a photoconductivity that is more than 1000 times this ratio, and is sufficiently distinguished from the carrier transport layer. obtain.

The layer thickness of the third layer region (8) is not more than 1 times, preferably not more than 1 times, optimally not more than 1 times, compared to the 201i region (7).
/4 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 electrophotographic photoreceptor of the second aspect of the present invention, in forming both or either of the second layer region (7) and the third layer region (8), a- 3i
It is characterized by containing He gas in the C generation gas, and this content is 5 times or less, preferably 0.5 to 3 times the total flow rate of CJ and St-containing gas. H-
It suffices to set the value within the range of , which prevents the ghost phenomenon from occurring.

Further according to a second aspect, a photoconductive a-5iC layer (5b
) are as shown in FIGS. 11 to 16, where the horizontal axis shows the layer thickness from the substrate to the surface of the photoreceptor, and the vertical axis shows the carbon content. Furthermore, on this horizontal axis,
The respective ranges shown in (6), (7), and (8) represent the first J1 region, the second layer region, and the third layer region.

According to FIGS. 12, 14, 15, and 16,
The carbon content is gradually changed over the layer thickness direction, which improves the surface potential, provides excellent photosensitivity, and reduces residual potential.

According to a third aspect of the present invention, there is provided a method for manufacturing an electrophotographic photoreceptor in which photoconductive a-3iC, which can be positively charged, is formed on a substrate by glow discharge decomposition of a-SiC generation gas. The gas is composed of C1□ and St-containing gas, and the composition ratio is set to 0.
．． C! during film formation.
H! The a-3iC layer has at least a first N jJ area, a second layer area, and a third N fin by changing the content composition ratio.
7181 area and a fourth N fil area are provided sequentially from the substrate side toward the photoreceptor surface, and the third 7181 area is provided in the second layer area, and the fourth M area is provided in the third layer area. When forming the second layer region, the a
-5iC generation gas contains 10- to 1 monolithic MA group element-containing gas, and when forming the first M region, a-
Provided is a method for manufacturing an electrophotographic photoreceptor, characterized in that the proportion of the Ma group element-containing gas in the 5iC generation gas is larger than that during the formation of the second layer region.

That is, according to the third person B, as shown in FIG.
A fourth layer region (9) is further formed on the third layer region (8) shown in the embodiment, and the fourth layer region (9) has a larger area than the third layer region (8). The first M 9M region (6) to the fourth layer region (9) were substantially integrated into a photoconductive a-SiCM (5c).

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

Further according to a third aspect, a photoconductive a-3iC layer (5C
) is as shown in FIGS. 18 to 21, where 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,
(6) (7) (8) The respective ranges shown in (9) are the first layer area, the second layer area, the third layer area and the fourth layer area.
It represents the 0 layer area.

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

According to the fourth aspect of Satorito Sarako, an electrophotographic image is produced in which photoconductive a-3icl and a-5iC surface protective layers which can be charged to positive polarity are sequentially formed by glow discharge decomposition of a-5iC generation gas. In the photoreceptor manufacturing method, the photoconductive a-5iC generating gas is composed of CJx and Si-containing gas, and the gas composition ratio is set to 0.
．． 01:1 to 3:1, and CL during film formation.
By changing the III-containing composition ratio, the a-5iC layer has a first layer region, a second layer region, and a third layer region, and the first layer region has a lower content than the second layer region. side, second
are arranged closer to the substrate than the third N region, and the third layer region contains more carbon than the second region, and when the first layer region is formed, the a -3iC
The generation gas contains 10 to 1 mol 2 of the NLA group element-containing gas, and when the first layer region is formed, the ratio of the 11[A group element-containing gas in the a-5iC generation gas to that of the second layer Provided is a method for manufacturing an electrophotographic photoreceptor characterized in that the area is larger than when it is formed.

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

The a-3iC surface protective layer (lO) 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.

Furthermore, according to the fourth aspect, the carbon content distribution is as shown in FIGS. 23 and 24, where the horizontal axis represents the layer thickness from the substrate to the photoreceptor surface, and the vertical axis represents the carbon content. There is. Furthermore, on this horizontal axis (6) (7) (8) (10)
The respective ranges shown in are the first MW region, the second layer region,
It represents the third layer region and the a-3iC surface protection layer.

Thus, according to the first to fourth aspects, an electrophotographic photoreceptor with significantly higher performance than the single-composition a-5iC photoreceptor shown in FIG. 1 is provided.

Further, according to the present invention, the a-3iC layer of a single composition and the a-5iCii of the first to third embodiments are both composed of a photoconductive a-SiC layer, which makes it possible to use electrophotography for practical use. However, a conventionally known surface protective layer may be formed on the surface of these a-3iC layers.

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. For example, organic materials such as polyimide resin + a-3i
C+SiOx+SiO+A1gO*+SiC, 5tJa
+a-5i*a-5i:H, a-3i:P, a-SiC
:H+a-SiC:F and other inorganic materials can be used.

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

In the figure, 1st. Second. Third. 4th. Fifth. 6th tank (1
1) (12) (13) (14) (15) (1
6), 5iHa and CgHz, respectively.

BJi (contains 0.2χ with Ile gas dilution) + BJ*(l
(contains 38 ppm when diluted with IE gas), He, and NO gas are sealed, and He is also used as a carrier gas4. These gases correspond to the first. Second. Third. 4th.
Fifth. Sixth regulating valve (17) (1B) (19) (2
0) (21) (22), and its flow rate is controlled by the mass flow controllers (23) (24).
)(25)(26)(27)(28), and the first, second . Third. 4th. 5th tank (11) (
12) (13) (14) The gas from (15) is sent to the first main pipe (29), and the He gas from the 6th tank (16) is sent to the second main pipe (30). Furthermore, (31) (32
) is a stop valve. The first main pipe (29) and the second main pipe (3
The gas flowing through 0) is sent to the reaction tube (33), and a capacitively coupled discharge electrode (34) is installed inside this reaction tube (33), and the high frequency power applied to it is 5 〇- to 3Kw, and the frequency is I MH
A cylindrical film-forming substrate (35) made of aluminum is placed inside the eight reaction tubes (33), which are suitable for a frequency of 10 MHz to 10 MHz.
is placed on a sample holder (36), which is rotated by a motor (37), and the substrate (35) is heated with appropriate heat. by means of about 200 to 400°C, preferably about 200°C.
It is uniformly heated to a temperature of 350°C to 350°C. Furthermore, the interior of the reaction tube (33) is connected to a rotary pump (38) and a diffusion pump (39) because a high degree of vacuum (discharge voltage 0.1 to 2.0 Torr) is required during a-5iC film formation. has been done.

In the glow discharge decomposition device configured as above,
For example, an a-5iC film (containing He and B) is deposited on a substrate (
35), the first. Second. Third. The fifth regulating valves (17), (1B), (19), and (21) are opened to release SiH*+CJx4Jm+He gas from each one. The release amount is determined by the mass flow controller (23) (
24) (25) Controlled by (27), 5iH1
+CJ*+B, HaJe mixed gas is in the first main pipe (29)
and into the reaction tube (33).

Then, the inside of the reaction tube (33) is 0.1 to 2.0 To
Vacuum state of about rr, substrate temperature 200 Th to 400
℃, the high frequency power of the capacitive discharge electrode (34) is set to 50 W to 3 Kw, or the frequency is set to 1 to 50 MHz, and a glow discharge occurs, and the gas decomposes and contains He and B. A-3iC film is formed on the substrate at high speed.

〔Example〕

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

(Example 1) In this example, a photoconductive a-5iC layer was formed on an aluminum film-forming substrate, and its conductivity with respect to the clog gas blending ratio was measured.

That is, using the capacitively coupled glow discharge decomposition device shown in FIG.
He gas is released from the fifth tank (15) at a flow rate of 100 seconds, and C2h gas is released from the second tank (12) at a flow rate of 10 to 100 seconds.
A-5iC with a thickness of about 5μ based on glow discharge decomposition method
When we fabricated the film and measured its dark conductivity and photoconductivity, we found that
The results shown in FIG. 26 were obtained.

According to Fig. 26, the horizontal axis is CJg gas flow rate (sccm)
, the vertical axis represents the conductivity [(Ω・cm)-'), the ・ mark is a plot of dark conductivity, and the o mark is a plot of the tle-Me laser (
This is a plot of photoconductivity when irradiated with light (wavelength: 632.8 nm, 100 pm W/cm"), and a and b are respective characteristic curves.

As is clear from Fig. 26, the dark conductivity is 10-'' (
Ω・cag)-' or less, with a minimum of 10-''C
Ω·cm)-' was obtained. Further, the photoconductivity was 1000 times or more as compared to the dark conductivity, indicating that this a-5iC layer had photoconductivity sufficiently satisfactory for use in electrophotographic photoreceptors.

(Example 2) In this example, when 82H&gas (or PR gas) was introduced and the dark conductivity and photoconductivity were measured based on (Example 1), the results shown in Figure 27 were obtained. It was done.

In the figure, the horizontal axis is B relative to the total flow rate of 5iHe and CxH*.
zHi pure amount (this represents the absolute flow rate of BmH & calculated from the dilution ratio of He gas);
B! A case where the pure amount of H is replaced with the pure amount of pus is also described as a reference example.

According to FIG. 27, the mark is a plot of dark conductivity,
Mark Q is a plot of photoconductivity (this photoconductivity is determined in the same manner as in (Example 1)), and C.

d is each characteristic curve.

As is clear from FIG. 27, the photoconductivity is more than 1000 times higher than the dark conductivity, indicating that the a-SiC layer doped with P and B along with He has photoconductivity that is satisfactory for use in electrophotographic photoreceptors. .

(Example 3) In this example, the spectral sensitivity characteristics are measured for the a-3iC layer obtained by setting the medium CI II 2 gas flow rate to lO105c in (Example 1), and the results are shown in Figure 28. The spectral sensitivity curve e is 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 czuz gas flow rate is 103
The a-3iC layer (thickness 30
The characteristics of surface potential, dark decay, and light decay were measured with respect to um). This measurement was performed by positively charging with a +5.6KV corona charger, and measuring the change in surface potential over time in the dark.
This figure follows the change in surface potential over time immediately after irradiation with 650n+s monochromatic light.

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

As is clear from FIG. 29, the surface potential is as large as about +620V, and the dark decay is about 27χ 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-3iCPJ obtained in (Example 4) was heated to -5,6K
When negatively charged in a V corona charge, the surface potential was several tens of V.

When the He content of the a-SiC photoconductor manufactured based on this (Example 4) was measured, it was approximately 0.1 atom χ, and this photoconductor was connected to the positive electrode using a +5.6KV corona charger. As a result of electrostatic charging, imagewise exposure, and magnetic brush development, a high-quality image with high image density, high contrast, and no ghost phenomenon was obtained. However, instead of introducing He gas as described above, H2 gas was introduced at 1
A ghost phenomenon appeared in the electrophotographic photoreceptor manufactured under the same conditions except that a flow rate of 00 scc was introduced.

(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. 12) from C1H! BzHi gas from the third and fourth tanks (13) (14), He gas from the fifth tank (15), and He gas from the sixth tank (15).
6), He gas was released, and the first layer region and the second layer region were formed under the manufacturing conditions shown in Table 1.

The thus obtained photoreceptor was positively charged in a corona charge connected to a +5.6 KV high voltage source in the dark.
Next, the surface of the photoreceptor was irradiated with spectrally monochromatic light (650 nm), thereby obtaining the following electrophotographic characteristics. Note that the residual potential is the value 5 seconds after the start of n-light.

Surface potential...+730v Photosensitivity...0.42c+s"erg-'Residual potential...
・29V Next, as in (Example 4), it was charged to positive polarity, then imagewise exposed and developed with a magnetic brush. As a result, the image density was high,
A high-quality image with high contrast and no ghost phenomenon was obtained.

However, the carrier gas (He gas 10 fin used in forming the first NeM region and the second 11 fin region
1005c flow rate) and the diluent He gas of BJi (containing 0,2χ) used to form the first layer region was replaced with OX gas, and all other A ghost phenomenon was observed.

(Left below) (Example 6) In this example, a photoreceptor of the second embodiment was manufactured in the same manner as in (Example 4).

The manufacturing conditions were as shown in Table 2, and the electrophotographic characteristics were as shown below, with no ghost phenomenon occurring at all.

Surface potential...+770V Photosensitivity...0.39c ■Rerg -1 residual type...
・25V However, the carrier gas (He gas 101005c flow rate) used in forming the first layer region and B11
16 (contained in 0 and 2), BJ used for forming the second layer region, and 11e gas (containing 38 ppm) for dilution were replaced with H gas, and the other conditions were exactly the same. A ghost phenomenon was observed in the produced electrophotographic photoreceptor.

(Left below) (Example 7) - In this example, a photoreceptor of the third embodiment was manufactured under the conditions shown in Table 3, and the following electrophotographic properties were obtained. Further, no ghost phenomenon occurred at all.

Surface potential...+800v, photosensitivity...0.40cm"erg-'residual potential...
...35V Furthermore, 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
In the figure, h and i are the dark decay curve and the light decay curve, respectively.

As is clear from FIG. 30, the surface potential is significantly large at about -750V, and the dark decay is about 20χ after 5 seconds, indicating excellent charge retention ability.

(Left below) (Example 8) In this example, a photoreceptor of the fourth embodiment was manufactured under the conditions shown in Table 4, and the following electrophotographic properties were obtained. Further, no ghost phenomenon occurred at all.

Surface potential...+900V Photosensitivity...J, 40cm"erg-' Residual potential...45V (hereinafter blank) [Effects of the Invention] As described above, according to the method for manufacturing an electrophotographic photoreceptor of the present invention,
Since a-3iC, which has photoconductivity throughout the entire layer, has a high resistivity and excellent photosensitivity characteristics, a surface protection layer and a carrier injection blocking layer are virtually unnecessary. As a result, an electrophotographic photoreceptor consisting only of photoconductive a-3iCli could be provided. Furthermore, according to the manufacturing method of the present invention, by incorporating a predetermined amount of He gas into the a-5iC generation gas, the ghost phenomenon does not occur, and as a result, an electrophotographic photoreceptor with even higher performance can be provided. Furthermore, improvements in overall electrophotographic properties can be expected as the film quality improves.

Furthermore, according to the method for producing an electrophotographic photoreceptor of the present invention, by changing the content of carbon and MA group elements in the layer thickness direction, the surface potential is improved, the photosensitivity characteristics are enhanced, and the residual potential is significantly reduced. Can be made smaller. In particular, when the carbon content is varied in the layer thickness direction, the resistivity can be controlled and a desired layer area can be obtained, and as a result, an electrophotographic photoreceptor with significantly higher performance can be provided.

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

According to the manufacturing method of the electrophotographic photoreceptor of the present invention, since the electrophotographic photoreceptor itself has excellent charging ability and environmental resistance, there is no need to provide a special protective layer, and, for example, it is not necessary to provide a protective layer. 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 can be 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 conventional A-3T exposure is used for a long period of time, local discharge waves are likely to occur on the surface of the photoreceptor due to corona discharge, which causes spots on the image. However, according to the manufacturing method of the present invention, a
-3t has a dielectric constant of ε-12, while a-3iC
is about half that of ε・7, so it has excellent charging ability.As a result, the above-mentioned discharge breakdown does not occur even if the surface potential is increased, and as a result, high-quality and highly reliable electronic We can provide photographic photoreceptors.

Furthermore, when the electrophotographic photoreceptor obtained by the manufacturing method of the present invention is compared with the conventional a-5i photoreceptor, problems with this a-Si photoreceptor include poor moisture resistance, which tends to cause image deletion, and , a ghost phenomenon occurs due to poor charging ability, but in order to solve this problem, when using an a-Si photoreceptor, a heater is used to heat the photoreceptor to prevent 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, the electrophotographic photoreceptor obtained by the manufacturing method of the present invention has a
-Compared to a Si photoreceptor, a wide range of spectral sensitivity characteristics (peak 600 to 700 na+) can be obtained by simply changing the carbon content, and the photosensitivity itself can be increased, and if necessary, it can be doped with impurity elements. This has the advantage that sensitization 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. 4, 5, 6, and 7
8 and 9 respectively show the first B according to the present invention.
FIG. 1θ is an explanatory diagram showing the layer region of a second photoconductor according to the present invention, FIG. 11, FIG. 12, FIG. 13, FIG. 14, 15, and 16 are explanatory diagrams showing the carbon content of the photoreceptor of the second embodiment of the present invention, respectively, and FIG. 17 is an explanatory diagram showing the carbon content of the photoreceptor of the third embodiment of the present invention
FIG. 18, FIG. 19, FIG. 20, and FIG. 21 are explanatory diagrams showing the carbon content of the photoconductor according to the third embodiment of the present invention, respectively. , FIG. 22 is an explanatory diagram showing the layer region of the photoconductor of the fourth embodiment of the present invention, and FIGS. 23 and 24 are explanatory diagrams showing the carbon content of the photoconductor of the fourth embodiment of the present invention. Figure 25 is an explanatory diagram of a capacitively coupled glow discharge decomposition device used in an embodiment of the present invention, Figure 26 is a diagram showing the conductivity versus the flow rate ratio of C2 and gas, and Figure 27 is a diagram showing the conductivity of Mh gas. Figure 28 is a diagram showing the spectral sensitivity characteristics of the amorphous silicon carbide layer, and Figure 29 is a diagram showing the dark attenuation and optical attenuation of the amorphous silicon carbide layer. 30 are diagrams showing the dark decay and light decay of the amorphous silicon carbide layer of the third embodiment. l...Substrate 5.5a, 5b, 5c...Photoconductive amorphous silicon carbide layer 6...First i region 7...Second layer region 8...Third layer region 9...Fourth 7! Region 10...Amorphous silicon carbide surface protective layer 2nd addition 85N26 (几C sacrificial)''C nide IV/(SiI 1 body-1-Cλ city)b...1)
+ u2L12 5il14 + (,211
Z second out! -17LTrL time (sec)

Claims (1)

[Claims] It consists of acetylene and silicon-containing gas, and the gas composition ratio is set within the range of 0.01:1 to 3:1,
Grow an amorphous silicon carbide producing gas containing 10^-^6 to 1 mol% of a gas containing Group IIIa elements of the periodic table, in which helium gas is blended at 5 times or less with respect to the total flow rate of these gases. A method for manufacturing an electrophotographic photoreceptor, characterized by forming an amorphous silicon carbide layer on a substrate, which can be positively charged, by decomposition by discharge.