JPH04329882A - Formation of deposited film by microwave plasma cvd method - Google Patents

Abstract

PURPOSE:To stably form a deposited film having excellent appearance at a high speed by applying a specific external bias voltage to a conductive base body at the time of producing the functional deposited film by a microwave plasma CVD method using the external bias in combination. CONSTITUTION:The inside of a vacuum vessel 101 having a conductive cylindrical base body 105 to be formed with an amorphous Si film, a dielectric window 102 for introducing microwaves, a gaseous raw material introducing pipe 11 for gaseous silane, gaseous hydrogen, etc., and a heater 107 is evacuated from a discharge D 104 to a vacuum. The gaseous raw materials are supplied from the gas introducing pipe 111 into the vacuum vessel 101 and the base body 105 is heated by a heater 107. The microwaves are simultaneously introduced through the dielectric window 102 of quartz glass, etc., into the vessel 101 to form microwave discharge plasma in a discharge space 106. An amorphous Si film is formed on the surface of the base body 105 by the gaseous raw materials. An electrode 108 disposed in the discharge space 106 is regulated to 0V at the point of the time to induce the microwave discharge plasma therein and to a desired voltage as the external bias voltage after the discharge is induced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a deposited film by microwave plasma CVD, and more particularly to an improved method for forming a deposited film by microwave plasma CVD, which is suitable for manufacturing electrophotographic photoreceptors.

0002

[Description of the Prior Art] Conventionally, hydrogen and/or Or amorphous silicon (hereinafter referred to as "a-Si(H,X)" compensated with halogen (e.g. fluorine, chlorine, etc.)
amorphous silicon carbide (hereinafter referred to as "a-SiC(H,X)"), hydrogen and/or halogen (e.g. fluorine, chlorine, etc.) ) compensated amorphous silicon nitride (hereinafter referred to as a-SiN(H,X)
Non-single-crystalline deposited films such as those described in ``Diamond'' have been proposed, and crystalline deposited films such as diamond thin films have been proposed, and some of these have been put into practical use.

Conventionally, an RF plasma CVD method has been put into practical use as a method for depositing such an amorphous semiconductor. However, the RF plasma CVD method has problems such as low raw material gas utilization efficiency, slow film deposition rate, and high product cost.

In order to solve the problems of the RF plasma CVD method, in recent years, a microwave plasma CVD method (hereinafter referred to as "μW-PC") using microwave glow discharge decomposition has been developed.
VD method) has been proposed. The μW-PCVD method has the advantage of higher deposition speed and raw material gas utilization efficiency than other methods, and is attracting industrial attention from the viewpoint of improving the productivity of deposited films and reducing costs. ing. An example of a .mu.W-PCVD apparatus that takes advantage of the above-mentioned advantages is described in Japanese Patent Application Laid-open No. 186849/1984. In the device described in this publication, a base body is arranged so as to substantially surround a means for introducing microwave energy to form an internal chamber (ie, a discharge space) to improve gas utilization efficiency.

Furthermore, Japanese Patent Laid-Open No. 61-283116 discloses an improved microwave technique for manufacturing semiconductor components. In other words, this publication discloses that an electrode is provided in the plasma space to control the plasma potential, and a desired voltage is applied to this electrode to perform film deposition while controlling ion bombardment to the deposited film, thereby improving the properties of the deposited film. Discloses technology that allows

[0006] These conventional methods have made it possible to produce a photoconductive material having a relatively thick film thickness and good electrical properties at a reasonably high deposition rate and raw material gas utilization efficiency.

Conventional μW-PC improved in this way
For example, in the case of manufacturing an electrophotographic photoreceptor, a deposited film forming apparatus using the VD method is typically used in the schematic vertical cross-sectional view of FIG. 1 and the schematic cross-sectional view of FIG. Fig. 1 is a schematic cross-sectional view of the apparatus shown in Fig. 1).

In FIGS. 1 and 2, 101 is a reaction vessel, which has a vacuum-tight structure. Further, 102 is a dielectric window for introducing microwaves made of a material (for example, quartz glass, alumina ceramics, etc.) that can efficiently transmit microwave power into the reaction vessel and maintain vacuum tightness. Reference numeral 103 denotes a microwave power transmission section, which is made of a waveguide and is connected to a microwave power source (not shown) via a stub tuner (not shown) and an isolator (not shown). The dielectric window 102 is the waveguide 1
It is hermetically sealed in the wall of 03. Reference numeral 104 is an exhaust pipe whose one end opens into the reaction vessel 101 and whose other end communicates with an exhaust system (not shown). Reference numeral 106 indicates a discharge space surrounded by a plurality of conductive cylindrical substrates 105. Reference numeral 108 denotes an electrode for applying an external electric bias (hereinafter referred to as "external bias") for controlling the plasma potential, and a DC or AC voltage is applied by a power source 109. Note that both conductive cylindrical substrates are placed on a cylindrical holder and heated by a heater 107.
Each holder is appropriately rotated by a driving means (rotary motor) 110.

[0009] Formation of a deposited film using such a deposition forming apparatus is carried out as follows.

First, the inside of the reaction vessel 101 is evacuated by a vacuum pump (not shown) through the exhaust pipe 104, and the pressure inside the reaction vessel, that is, the internal pressure is adjusted to about 1×10 −7 Torr or less. Next, the conductive cylindrical substrate 105 is heated and maintained at a temperature suitable for film deposition by the heater 107.

In this state, a raw material gas such as silane gas or hydrogen gas is introduced into the reaction vessel 101 through the gas introduction pipe 111 if an amorphous silicon deposited film is to be formed. Next, a microwave power source (not shown) is used to generate a frequency of 500 MHz or more, preferably 2
．． A microwave of 45 GHz is generated and transmitted to the reaction vessel 1 via the microwave waveguide 103 and the dielectric window 102.
Introduced into 01. In parallel with this, a power source 10 is applied to the electrode 108 provided in the discharge space 106 as an external bias.
From step 9, for example, a DC voltage is applied. In the discharge space 106 formed by being surrounded by the plurality of conductive cylindrical substrates 105, the raw material gas is excited by the microwave energy and dissociated, and all the conductive cylindrical substrates 10 are dissociated.
A deposited film is formed on the surface of 5. At this time, by rotating all the conductive cylindrical substrates 105 about the central axis in the direction of the substrate generatrix, a deposited film is formed on the entire surface of each conductive cylindrical substrate.

0012

[Problem to be solved by the invention] Such conventional μW
- According to the deposited film forming apparatus and method using the PCVD method,
For a certain area, it is relatively easy to obtain a deposited film with practical characteristics and uniformity. However, in these conventional methods for forming a deposited film using the μW-PCVD method, when forming a deposited film with a large area such as a photoreceptor for electrophotography, an external bias voltage is required to obtain a deposited film with particularly good characteristics. When this was applied, cloudy stains (hereinafter referred to as "stains") were sometimes generated on the surface of the resulting deposited film. Such "stains" not only significantly deteriorate the quality of the appearance of the deposited film, resulting in so-called poor appearance, but also
This even affects the properties of the deposited film, and has been a cause of deterioration of the yield in producing the deposited film.

[0013]

[Means for Solving the Problems] An object of the present invention is to overcome the problems in the conventional deposited film forming method as described above, and to improve semiconductor devices, electrophotographic photoreceptor devices, line sensors for image input, Functional deposited films with excellent properties useful for element members used in photovoltaic devices, imaging devices, thin film transistors, various other electronic devices, optical devices, etc. can be produced at a high deposition rate and by the μW-PCVD method. An object of the present invention is to provide an improved method for forming a deposited film that can be formed stably and with a high yield.

Another object of the present invention is to provide a method for forming a high quality functional deposited film with uniform properties over a large area.

Still another object of the present invention is to provide a non-single-crystalline deposited film such as an amorphous silicon deposited film, which is improved by the μW-PCVD method and can form a film with excellent appearance and properties. The object of the present invention is to provide a forming method.

[0016] The present inventors have conducted intensive research to overcome the above-mentioned problems in the conventional deposited film forming method and achieve the above-mentioned object of the present invention, and have obtained the following findings. .

The present invention has been completed based on this knowledge, and its gist is that a conductive substrate is placed in a reaction vessel that can be substantially sealed so as to surround a discharge space, A microwave introducing means is provided to form a discharge plasma containing a reactant that contributes to film formation derived from the raw material gas, and a voltage is applied to an electrode provided in the discharge space to form a deposited film on the surface of the substrate. In the method, at the time of generating the microwave plasma, the voltage applied to the electrode is set to 0 V with respect to the conductive substrate, and after the discharge occurs, the microwave power is applied to the desired level necessary for forming the deposited film. This method of forming a deposited film is characterized by comprising a step of applying a desired voltage to the electrode after adjusting the voltage to a desired value.

[0018] The findings experimentally obtained by the present inventors and the content of the present invention will be explained below. In the conventional microwave plasma CVD method, the frequency of the microwave is, for example, 2
．． Since the frequency is as large as 45 GHz, the ion sheath formed by electrons, ions, etc. generated by decomposition of the source gas becomes extremely narrow. Therefore, in the conventional microwave plasma CVD method, the surface mobility of the active species for forming the deposited film in the deposited film on the support and in the growth region of the deposited film on the surface of the deposited film varies depending on the plasma temperature and the support temperature. Since it is uniquely determined, it has not been possible to increase the size to a sufficient extent to improve the structure and electrical characteristics of the deposited film.

That is, when a deposited film is formed by plasma CVD, hydrogen atoms are removed from the surface of the deposited film and constituent atoms are rearranged to form more stable bonds on the surface of the substrate. These reactions are essential for obtaining a deposited film with good properties, and are generally promoted by thermal energy. However, when a deposited film is formed on a substrate at high speed by microwave plasma CVD, the heat of the substrate alone is insufficient in energy to cause a sufficient surface reaction.

[0020] As a method for solving the problems of the μW-PCVD method and obtaining a deposited film having good structure and electrical characteristics, an external bias method is proposed as shown in Japanese Patent Application Laid-Open No. 61-283116. A method has been proposed in which this method is used in conjunction with microwave plasma discharge. That is, an electrode is provided in the discharge space, an external bias voltage is applied to this electrode, an electric field is applied between the plasma and the conductive substrate, and ion bombardment is applied to the conductive substrate or the deposited film, thereby generating localized energy. Annealing can be performed to promote surface reactions. In this sense, the external bias is μW-PCV
This is a very effective technique for forming deposited films at high speed using the D method.

However, when a deposited film is formed using an external bias, cloudy cloudy "stains" often appear on a portion of the surface of the deposited film. This "stain"
Also, when observing the surface of a deposited film using an electron microscope,
Although it can only be distinguished from a normal part as a slight difference in the grain size of the film structure that occurs during the deposition process, when observing the surface with the naked eye, the normal part is clearly cloudy and lacks luster. This significantly worsened the appearance of the deposited film. Furthermore, the properties of the deposited film are affected, and in the case of electrophotographic photoreceptors, for example, the properties of the deposited film are poor, such as uneven density on the image.

The present inventors analyzed in detail the causes of such "stains" and conducted repeated experiments on means to solve this problem. As a result, the inventors found that the external It became clear that the bias voltage was related to the generation of "spots", and furthermore, when generating the discharge, the external bias voltage was set to 0 V with respect to the conductive substrate, and the microwave power was adjusted to the desired power necessary for forming the deposited film. By applying a desired external bias voltage after the deposition, not only does it prevent the occurrence of "stains" and contribute to improving the yield, but it also improves the uneven properties of the deposited film and improves its quality. We have come to this conclusion.

[0023] The findings obtained by the present inventors will be explained in more detail below.

Although the detailed mechanism for the generation of "stains" remains unclear, it is thought that the mechanism is roughly as follows.

When a raw material gas is introduced into the discharge space and microwave power is applied to generate a discharge in order to form a deposited film, the active species generated at the moment of generation of the discharge have a very high excess. These active species are bombarded by ions accelerated by an external bias voltage, causing some slight damage to the substrate surface or the initial deposited film, which progresses the film deposition. As the stain increases, it increases and is observed as a "stain", and it is thought that it also affects the characteristics of the deposited film.

[0026] The inventors of the present invention have conducted repeated experiments in order to eliminate the damage immediately after such discharge occurs and to obtain a means to prevent the occurrence of "stains". By setting the bias voltage to 0V and generating a discharge, the microwave power is adjusted to the desired power required for film deposition, and then the desired external bias voltage is applied to the electrodes to prevent the occurrence of "stains". It has become clear that this method is effective in homogenizing properties, and the present invention has been completed.

Hereinafter, a procedure for implementing the present invention will be explained using a deposited film forming apparatus suitable for implementing the present invention as shown in FIGS. 1 and 2.

First, the inside of the reaction vessel 101 is evacuated by a vacuum pump (not shown) through the exhaust pipe 104, and the pressure inside the reaction vessel, that is, the internal pressure is adjusted to about 1×10 −7 Torr or less. Next, the conductive cylindrical substrate 105 is heated and maintained at a temperature suitable for film deposition by the heater 107.

Therefore, in the case of forming, for example, an amorphous silicon deposited film, a raw material gas such as silane gas or hydrogen gas is introduced into the reaction vessel 101 through the gas introduction pipe 111, and the internal pressure is adjusted to 1×, for example. Try to maintain a vacuum level of 10-2 or less. Next, the microwave power source (
The 2.45 GHz microwave generated by
The power of the microwave introduced into the chamber is gradually increased to generate a discharge, and then adjusted to the desired microwave power necessary for forming a deposited film. After that, inside the discharge space 106
A power supply 1 is applied as an external bias to the electrode 108 provided in the
A predetermined voltage is applied from 09 onwards. A discharge space 1 is thus formed surrounded by a plurality of conductive cylindrical substrates 105.
In step 06, the raw material gas is excited by microwave energy and dissociated to form neutral radical particles, ionic particles,
Electrons and the like are generated and react with each other to form a deposited film on the surface of the conductive cylindrical substrate 105 on the discharge space 106 side. Then, by rotating all the conductive cylindrical substrates 105 around the central axis in the direction of the substrate generatrix, a deposited film is formed on the entire surface of each conductive cylindrical substrate.

[0030] Here, the microwave power required to form the deposited film is at least the minimum power capable of stably maintaining the discharge, and even when discharging for a long time as in the production of an electrophotographic photoreceptor. The input microwave power is within the maximum power range that does not cause damage to the microwave transmission window or peeling of the film. Specifically, it is determined appropriately depending on the type of deposited film to be created and the internal pressure of the discharge space, but it is 300 to 2000 W.
A range of is preferred.

In the present invention, the thickness of the deposited film from the time when the discharge occurs until the time when the microwave power is adjusted to the desired power and the external bias voltage is applied to the electrode installed in the discharge space is determined depending on the thickness of the deposited film. Although the effect of preventing "stains" is recognized even with a film thickness of 100 ml, it depends on the film deposition conditions due to the need for time to adjust the microwave power necessary for film deposition due to the generation of electric discharge. A thickness of 0.01 μm or more is desirable. Further, in order not to affect the characteristics of the deposited film, the film thickness is preferably 3 μm or less, and more preferably 1 μm or less.

Further, through the above-mentioned experiments, the following findings were obtained.

In the present invention, the reaction vessel may be made of any material as long as it maintains vacuum tightness and reflects microwaves, but aluminum, stainless steel, etc. are most suitable from the viewpoint of workability and durability.

[0034] In the present invention, a method for introducing the microwave to the reaction vessel includes a method using a waveguide, and a method for introducing the microwave into the reaction vessel includes a method for introducing it through one or more dielectric windows. . At this time, the material of the microwave introduction window into the reaction vessel is alumina (Al2O3).
, aluminum nitride (AlN), boron nitride (BN),
Silicon nitride (SiN), silicon carbide (SiC), silicon oxide (
Materials with low microwave loss are typically used, such as SiO2), beryllium oxide (BeO), Teflon, and polystyrene.

In the present invention, the pressure in the discharge space during the formation of the deposited film does not affect the effect;
Particularly good results were obtained with good reproducibility at a temperature of 30 mTorr or less, preferably 50 mTorr or less, and optimally 30 mTorr or less.

The heating means for the substrate in the present invention may be any vacuum type heating element, and more specifically, it may be a sheathed heater, a plate heater, an electric resistance heating element such as a ceramic heater, a halogen lamp, Examples include a heat radiation lamp heating element such as an infrared lamp, a heating element using a heat exchange means using liquid, gas, etc. as a heating medium, and the like. As the surface material of the heating means, metals such as stainless steel, nickel, aluminum, and copper, ceramics, heat-resistant polymer resins, and the like can be used.

In addition to the above, it is also possible to use a method in which a heating-only container is provided in addition to the reaction container, and after heating, the substrate is transported into the reaction container in a vacuum.

In the present invention, the raw material gas for the deposited film is as follows:
For example, amorphous silicon forming raw material gas such as silane (SiH4) and disilane (Si2H6), germane (Ge
Other functional deposited film forming raw material gases such as H4), methane (CH4), or mixed gases thereof may be used.

Examples of the diluent gas include hydrogen (H2), argon (Ar), and helium (He).

[0040] Gases for improving properties such as changing the band gap width of the deposited film include elements containing nitrogen atoms such as nitrogen (N2) and ammonia (NH3), oxygen (O2),
Elements containing oxygen atoms such as nitrogen oxide (NO) and dinitrogen oxide (N2O), hydrocarbons such as methane (CH4), ethane (C2H6), ethylene (C2H4), acetylene (C2H2), and propane (C3H8), and tetrafluorocarbons. Silicon oxide (SiF4
), fluorine compounds such as disilicon hexafluoride (Si2F6), germanium tetrafluoride (GeF4), or a mixed gas thereof.

[0041] Diborane (
B2H6), boron fluoride (BF3), phosphine (P
The present invention is equally effective even if a dopant gas such as H3) is simultaneously introduced into the discharge space.

In the present invention, the electric field generated between the electrode and the substrate is preferably a DC electric field, and it is more preferable that the electric field is directed from the electrode toward the conductive substrate. The average value of the DC voltage applied to the electrodes to generate an electric field is preferably 15 V or more and 300 V or less, preferably 30 V or more and 200 V or less. There are no particular restrictions on the DC voltage waveform, which is effective in the present invention. In other words, the direction of the voltage does not need to change with time. For example, the present invention can apply not only a constant voltage that does not change with time, but also a pulsed voltage and a pulsating voltage that is rectified by a rectifier and whose value changes with time. is valid.

It is also effective in the present invention to apply an alternating current voltage. There is no problem with the frequency of alternating current, and for practical purposes, 50Hz or 60Hz is the lowest frequency.
, 13.56 MHz is suitable for high frequency. The alternating current waveform may be a sine wave, a rectangular wave, or any other waveform, but a sine wave is suitable for practical use. However, in both cases, the voltage refers to the effective value.

In the present invention, the external bias voltage applied to the electrode provided in the discharge space when forming the photoreceptive layer may be kept constant until the formation of the deposited film is completed;
The value of the external bias voltage may vary from layer to layer. Furthermore, it is also effective in the present invention to gradually increase the value of the external bias voltage as the deposited film is formed after a predetermined external bias voltage is applied after discharge occurs.

[0045] The size and shape of the electrode may be such as long as it does not disturb the discharge, but in practice it is recommended to use a diameter of 1 mm or more
A cylindrical shape of cm or less is preferable. The length of the electrode can also be set arbitrarily as long as the electric field is uniformly applied to the base.

The material of the electrode may be any material whose surface is electrically conductive, such as stainless steel, Al, Cr,
Mo, Au, In, Nb, Te, V, Ti, Pt, Pd
, Fe and other metals, alloys thereof, glass, ceramics, plastics, etc. whose surfaces have been subjected to conductive treatment are generally used in the present invention.

[0047] Examples of the conductive base material include stainless steel, Al, Cr, Mo, Au, In, Nb, Te, and V.
, metals such as Ti, Pt, Pd, and Fe, alloys thereof, or synthetic resins such as polycarbonate whose surfaces are conductively treated,
Glass, ceramics, paper, etc. are commonly used in the present invention.

[0048] There is no particular restriction on the substrate temperature during the formation of the deposited film in the present invention, and when depositing amorphous silicon, the temperature is 20°C or higher and 500°C or lower, preferably 50°C or higher and 450°C or higher.
It is preferable that the temperature is below .degree. C. because it shows good effects.

Furthermore, the present invention provides a blocking type amorphous silicon photoreceptor, a high resistance type amorphous silicon photoreceptor, etc.
In addition to photoreceptors for copiers or printers, it can also be applied to the fabrication of any other device that requires a functional deposited film with good electrical properties.

The present invention is applicable to all devices using microwaves, but in particular, a conductive base is provided to surround a discharge space, and microwaves are transmitted from at least one end of the conductive base by a waveguide. This method has a great effect on devices configured to apply a voltage to electrodes provided in a discharge space.

[0051] Hereinafter, according to an experimental example, μW-PC of the present invention
The effects of the VD method for forming a deposited film will be explained. Experimental Example 1 Using the μW-PCVD deposited film forming apparatus shown in FIGS. 1 and 2, an aluminum cylinder with a length of 358 mm and an outer diameter of 108 mm was used as the conductive substrate, and according to the procedure detailed above. , as shown in FIG. 3, a conductive cylindrical substrate 201, a photoconductive layer 202, a surface layer 203
were sequentially formed under the manufacturing conditions shown in Table 1 to produce an electrophotographic photoreceptor. After the discharge occurs, the microwave power is adjusted to a predetermined power and the thickness of the deposited film is 0 μm until the external bias voltage is applied (external bias voltage is applied to the electrode before the discharge occurs). ) to 5 μm, and 10 lots of electrophotographic photoreceptors were produced under the same conditions.

The thus produced electrophotographic photoreceptor was visually inspected for the occurrence of "stains" on its appearance, and the number of lots in which "stains" occurred among the electrophotographic photoreceptors produced under the same conditions was determined. Those with 3 or more lots were evaluated as "△", those with 1 or 2 lots were evaluated as "○", and those with no "stains" at all were evaluated as "◎".

Furthermore, these electrophotographic photoreceptors were set in a modified Canon NP-7550 copying machine for experimental purposes, and the potential characteristics of charging ability, sensitivity, and residual potential, as well as halftone images were measured. The density unevenness was evaluated. These results are shown in Table 2.

In Table 2, the evaluations of charging ability, sensitivity, residual potential, and density unevenness of halftone images are as follows: ◎: Good ○: No problem in practical use △: Problem in practical use.

Table 2 shows that by applying an external bias voltage after generating a discharge, the occurrence of "stains" can be prevented, and density unevenness in halftone images is also improved. Also, the thickness of the deposited film from the time the discharge occurs until the external bias voltage is applied is 3 μm.
It was also found that sensitivity and residual potential begin to be affected when m is exceeded.

[0056]

[Examples] Specific examples will be described below to demonstrate the effects of the present invention, but the present invention is not limited by these in any way.

(Example 1) μW- shown in FIGS. 1 and 2
Using a deposited film forming apparatus using the PCVD method and using an aluminum cylinder with a length of 358 mm and an outer diameter of 108 mm as a conductive substrate, a conductive cylindrical shape was formed as shown in FIG. 4 according to the procedure detailed above. On the base 301,
A first photoconductive layer 302, a second photoconductive layer 303, and a surface layer 304 were sequentially formed according to the conditions shown in Table 3 to produce 10 lots of electrophotographic photoreceptors. In addition, in the first photoconductive layer, the film thickness was 0.05 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 3 and the external bias voltage was applied to the electrode. .

(Comparative Example) Ten lots of electrophotographic photoreceptors were prepared under the same conditions as in Example 1, except that an external bias voltage was applied to the electrodes before discharge occurred.

The electrophotographic photoreceptors prepared in Example 1 and Comparative Example were visually inspected for the occurrence of "stains" on the appearance. If the number of lots in which "" has occurred is 3 or more, "△"
1 to 2 lots were evaluated as "○", and those in which no "stain" occurred were evaluated as "◎".

Furthermore, these electrophotographic photoreceptors were set in a modified Canon NP-7550 copying machine for experimental purposes, and the potential characteristics of charging ability, sensitivity, and residual potential, as well as density unevenness in halftone images, were investigated. evaluated. These results are shown in Table 4.

In Table 4, the evaluations of chargeability, sensitivity, residual potential, and density unevenness of halftone images are as follows: ◎: Good ○: No practical problems △: Practical problems.

From Table 4, it was found that according to the present invention, a good electrophotographic photoreceptor having no "stains", excellent potential characteristics, and excellent uniformity of image characteristics could be obtained.

(Example 2) Using the same procedure as in Example 1, FIG.
As shown in FIG.
were sequentially formed under the conditions shown in Table 5 to produce 10 lots of electrophotographic photoreceptors. In addition, in the first photoconductive layer, the film thickness was 0.03 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 5 and the external bias voltage was applied to the electrode. . When the electrophotographic photoreceptor thus obtained was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 3) Using the same procedure as in Example 1, FIG.
As shown in Table 6, a charge injection blocking layer 402, a photoconductive layer 403, and a surface layer 404 were sequentially formed on a conductive cylindrical substrate 401 under the conditions shown in Table 6 to prepare an electrophotographic photoreceptor.
A lot was created. Further, in the charge injection blocking layer, the film thickness from the time when a discharge was caused to the time when the microwave power was adjusted to the power shown in Table 6 and the external bias voltage was applied to the electrode was 0.1 μm.

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 4) Using the same procedure as in Example 1, FIG.
As shown in FIG.
were sequentially formed under the conditions shown in Table 7 to produce 10 lots of electrophotographic photoreceptors. Further, in the first photoconductive layer, the film thickness was 1 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 7 and the external bias voltage was applied to the electrode.

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 5) Using the same procedure as in Example 1, FIG.
As shown in Table 8, a photoconductive layer 202 and a surface layer 203 were sequentially formed on a conductive cylindrical substrate 201 under the conditions shown in Table 8 to produce 10 lots of electrophotographic photoreceptors. Also,
In the photoconductive layer, the film thickness was 1 μm after the discharge was generated, the microwave power was adjusted to the power shown in Table 8, and the external bias voltage was applied to the electrodes.

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 6) Using the same procedure as in Example 1, FIG.
As shown in FIG.
were sequentially formed under the conditions shown in Table 9 to produce 10 lots of electrophotographic photoreceptors. In addition, in the first photoconductive layer, the film thickness was 0.03 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 9 and the external bias voltage was applied to the electrode. .

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 7) Using the same procedure as in Example 1, FIG.
As shown in Table 10, a first photoconductive layer 302, a second photoconductive layer 303, and a surface layer 304 are sequentially formed on a conductive cylindrical substrate 301 under the conditions shown in Table 10 to obtain an electrophotographic photosensitive material. I made 10 lots of bodies. In addition, in the first photoconductive layer, the film thickness was 0.1 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 10 and the external bias voltage was applied to the electrode. .

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 8) Using the same procedure as in Example 1, FIG.
As shown in Table 11, a charge injection blocking layer 502, a first photoconductive layer 503, a second photoconductive layer 504, and a surface layer 505 are sequentially formed on a conductive cylindrical substrate 501 under the conditions shown in Table 11. Then, 10 lots of electrophotographic photoreceptors were prepared. Also,
In the charge injection blocking layer, the film thickness was 0.1 μm after the discharge was caused and the microwave power was adjusted to the power shown in Table 11 and the external bias voltage was applied to the electrode.

When the thus obtained electrophotographic photoreceptor was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

(Example 9) Using the same procedure as in Example 1,
As shown in FIG.
were sequentially formed under the conditions shown in Table 12 to produce 10 lots of electrophotographic photoreceptors. In addition, in the first photoconductive layer, the film thickness was 0.5 μm after the discharge was generated until the microwave power was adjusted to the power shown in Table 12 and an external bias voltage was applied to the electrode. . When the electrophotographic photoreceptor thus obtained was evaluated for electrophotographic properties in the same manner as in Example 1, good results were obtained as in Example 1.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

[0080]

[Table 4]

[0081]

[Table 5]

[0082]

[Table 6]

[0083]

[Table 7]

[0084]

[Table 8]

[0085]

[Table 9]

[0086]

[Table 10]

[0087]

[Table 11]

[0088]

[Table 12]

[0089]

[Effects of the Invention] As explained above, according to the present invention,
In a method for manufacturing a functional deposited film by a microwave plasma CVD method using an external bias, the external bias voltage is set to 0 V with respect to the conductive substrate at the start of discharge, and a predetermined external bias voltage is applied after the discharge is generated. By doing so, it becomes possible to rapidly and stably obtain a deposited film with no "stains" and excellent appearance. Particularly in the formation of deposited films over large areas such as electrophotographic photoreceptors, it is possible to supply a homogeneous film with even characteristics, thereby improving the quality of the product and its yield.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing a deposited film forming apparatus using a microwave plasma CVD method that can be used in carrying out the present invention.

FIG. 2 is a schematic cross-sectional view of the device in FIG. 1.

FIG. 3 is a schematic cross-sectional view showing the layer structure of an electrophotographic photoreceptor prepared in an experimental example of the present invention.

FIG. 4 is a schematic cross-sectional view showing the layer structure of the electrophotographic photoreceptor produced in Example 1 of the present invention.

FIG. 5 is a schematic cross-sectional view showing the layer structure of an electrophotographic photoreceptor produced in Example 3 of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining the layer structure of an electrophotographic photoreceptor produced in Example 8 of the present invention.

[Explanation of symbols]

101 Reaction container 102 Microwave introduction window 103 Waveguide 104 Exhaust pipe 105 Conductive cylindrical substrate 106 Discharge area 107 Heater 108 Electrode 109 Power supply 110 Motor 111 Raw material gas introduction pipe 201 Conductive cylindrical substrate 202 Photoconductive layer 203 Surface layer 301 Conductive cylindrical substrate 302 First photoconductive layer 303 Second photoconductive layer 304 Surface layer 401 Conductive cylindrical substrate 402 Charge injection blocking layer 403 Photoconductive layer 404 Surface layer 501 Conductive cylindrical substrate 502 Charge injection blocking layer 503 First photoconductive layer 504 Second photoconductive layer 505 Surface layer

Claims (2)

[Claims] 1. A conductive substrate is disposed so as to surround a discharge space formed in a reaction vessel that can be substantially sealed,
By the action of microwaves, a microwave discharge plasma containing a reactant derived from the source gas and contributing to film formation is formed, and an external electric bias voltage is applied between an electrode provided in the discharge space and the conductive substrate. In the deposited film forming method of forming a deposited film on the surface of the substrate, an external bias voltage to the conductive substrate is set to 0 V when forming a microwave discharge plasma, and a predetermined external electric bias voltage is applied after discharge occurs. A method for forming a deposited film, comprising the step of applying an electric voltage. 2. The method for forming a deposited film according to claim 1, wherein the deposited film constitutes a light-receiving layer of an electrophotographic photoreceptor.