JPH07183228A - Deposited film forming device - Google Patents

Abstract

PURPOSE:To provide a deposited film forming device by a microwave plasma CVD method which forms a deposited film having uniform characteristics and a uniform thickness at a high speed and a high yield over the entire surface of a substrate. CONSTITUTION:A deposited film forming device constituted in such a way that multiple cylindrical base substrates 105 are arranged so as to surround a discharging space 106 in an evacuatable reaction chamber 101 and a gas discharging nozzle 108 for introducing a gaseous starting material into the discharging space and means 103 which are counterposed to each other along a generating line in the discharging space and introduce microwave energy to the discharging space are provided, and then, bias voltage applying means 111 are provided between the nozzle 108 and each cylindrical substrate. In addition, gas tubes 112 and 113 which are connected to the nozzle 108 are symmetrically arranged in the vertical direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deposited film, especially a functional film, on a cylindrical substrate, especially a semiconductor device, a photoconductor device for electrophotography, a line sensor for image input, an image pickup device, a photovoltaic device and the like. The present invention relates to a deposited film forming apparatus for forming an amorphous deposited film to be used by a microwave plasma CVD method.

[0002]

2. Description of the Related Art Conventionally, amorphous silicon, such as hydrogen, has been used as an element member for semiconductor devices, electrophotographic photoconductor devices, image input line sensors, image pickup devices, photovoltaic devices, other various electronic elements, optical elements and the like. Alternatively, and / or an amorphous deposited film such as amorphous silicon compensated with halogen (eg, fluorine, chlorine, etc.) has been proposed, and some of them have been put to practical use.

Conventionally, as a method of forming such a deposited film, a sputtering method, a method of decomposing a raw material gas by heat (thermal CVD method), and a method of decomposing a raw material gas by light (optical CV).
D method), a method of decomposing a raw material gas by plasma (plasma CVD method), and the like are known. Among them, the plasma CVD method, that is, the source gas is DC or high frequency,
The method of forming a thin film deposition film on a substrate such as glass, quartz, heat-resistant synthetic resin film, stainless steel, aluminum, etc. by decomposing by microwave glow discharge is applied to electrophotographic amorphous silicon deposition film, etc. At present, it has been extremely put into practical use, and various devices for it have been proposed. In particular, in recent years, a plasma CVD method using microwave glow discharge decomposition, that is, a microwave plasma CVD method has been industrially attracting attention as a deposited film forming method.

The microwave plasma CVD method has the advantages of a higher deposition rate and a higher utilization efficiency of the source gas than other methods. One example of microwave plasma CVD technology that takes advantage of these advantages is US Pat.
No. 504,518. The technique described in this patent is to obtain a good quality deposited film at a high deposition rate by a microwave plasma CVD method at a low pressure of 0.1 Torr or less.

Further, a technique for improving the utilization efficiency of the raw material gas by the microwave plasma CVD method is disclosed in Japanese Patent Laid-Open No. Sho 60-60.
No. 186849. The technique disclosed in this publication is, in general, arranged so as to surround a means for introducing microwave energy so as to form an internal chamber (that is, a discharge space) so that the utilization efficiency of the raw material gas is greatly enhanced. It was done.

Further, Japanese Patent Laid-Open No. 61-283116 discloses an improved microwave technique for manufacturing a semiconductor member. That is, according to this publication, an electrode (bias electrode) is provided as a plasma potential control in the discharge space, and a desired voltage (bias voltage) is applied to this bias electrode to control the ion bombardment of the deposited film while performing film deposition. A technique for improving the characteristics of the deposited film as disclosed is disclosed.

In such a microwave plasma CVD apparatus, an improvement of the raw material gas introduction part is disclosed in JP-A-63-230.
880. These are methods of introducing the raw material gas into the discharge space from between the cylindrical substrates. By making the shape of the raw material gas introduction part comb-shaped or triangular, the raw material gas is efficiently introduced into the plasma generation region. ,
It is possible to improve the deposition rate of the deposited film.

Japanese Patent Application Laid-Open No. 3-219081 describes an improvement of the raw material gas introduction part. That is, in this publication, the source gas introducing section also serves as the bias electrode, whereby bias energy is effectively applied to the decomposition species to improve the characteristics of the deposited film.

Further, in Japanese Patent Laid-Open No. 4-26764, as a further improvement of the raw material gas introducing portion, the raw material gas introducing portion is provided inside the discharge space and has a multi-tube structure, so that the axial direction of the substrate is improved. A deposition film forming apparatus that improves unevenness in film thickness is disclosed.

These conventional techniques have made it possible to produce a relatively thick photoconductive material with a somewhat high deposition rate and the efficiency of using the source gas. The conventional deposited film forming apparatus thus improved is implemented as follows as a deposited film forming apparatus for producing the electrophotographic photosensitive drum shown in the sectional view of FIG.

In FIG. 5, reference numeral 501 denotes a reaction vessel having a vacuum airtight structure. Reference numeral 502 is a microwave introduction dielectric window formed of a material (for example, quartz glass, alumina ceramics, etc.) capable of efficiently transmitting microwave power into the reaction vessel and maintaining vacuum tightness. Reference numeral 503 denotes a waveguide for transmitting microwave power, which is composed of a rectangular portion from the microwave power source to the vicinity of the reaction container and a cylindrical portion inserted in the reaction container. The waveguide 503 is connected to a microwave power source (not shown) together with a stub tuner (not shown) and an isolator (not shown). The dielectric window 502 is hermetically sealed to the cylindrical portion and inner wall of the waveguide 503 to maintain the atmosphere in the reaction vessel. Reference numeral 504 is an exhaust pipe having one end opening into the reaction vessel 501 and the other end communicating with an exhaust device (not shown). 506 is the base 5
The discharge space surrounded by 05 is shown.

Formation of a deposited film on an electrophotographic photosensitive member by such a conventional deposited film forming apparatus is performed as follows.
First, the reaction vessel 501 is evacuated through the exhaust pipe 504 by a vacuum pump (not shown), and the pressure in the reaction vessel 501 is adjusted to 1 × 10 ⁻⁶ Torr or less. Then, the heater 507 heats and holds the temperature of the substrate 505 at a temperature suitable for film deposition. Therefore, in the case of forming an amorphous silicon deposited film, for example, a raw material gas such as silane gas is introduced into the reaction vessel 501 through the branch pipe 512 and the gas emission nozzle 508 from the gas emission nozzle 508. A bias voltage is applied to the gas discharge nozzle 508 from a bias power supply 511. At the same time, a microwave power source (not shown) is used to generate a microwave having a frequency of 500 MHz or higher, preferably 2.45 GHz, and the waveguide 50
3, microwave energy is introduced into the reaction vessel 501 through the dielectric window 502. Thus the substrate 50
In the discharge space 506 surrounded by 5, the source gas is excited by the energy of the microwaves and dissociated, and the electric field between the gas discharge nozzle 508 and the base 505 constantly causes ion bombardment on the base 505. While the substrate 50
5 A deposited film is formed on the surface. At this time, the rotating shaft 509 on which the substrate 505 is installed is rotated by the motor 510, and the substrate 505 is rotated around the central axis in the substrate generatrix direction, whereby a deposited film is formed uniformly over the entire circumference of the substrate 505. It

With such a conventional deposited film forming method, it is possible to obtain a deposited film having practical characteristics and uniformity at a certain deposition rate. However, in these conventional deposited film forming methods, the respective characteristics of the electrophotographic photosensitive member could be satisfied by optimally setting the film forming parameters, but a large number of photosensitive members can be formed by one film forming process. In the case of batch production in which film formation is performed simultaneously, it is difficult to set film formation parameters that satisfy all electrophotographic photoreceptors. Especially in the area where the deposition rate is high, and when manufacturing a product such as an electrophotographic photoconductor that requires a large area and a relatively thick deposited film, variations in characteristics are observed between photoconductors within one batch. There were many times when I was told. Therefore, in the conventional production apparatus, it was a reality that the manufacturing conditions were finely adjusted so that the characteristics of the electrophotographic photosensitive member in one batch were within the specifications, and the compromise was made to some extent. Therefore, it is possible to consistently obtain a deposited film with a uniform film quality that satisfies the requirements of various optical and electrical characteristics and has few image defects at the time of image formation by an electrophotographic process with high yield (high yield). There was a problem to be solved that was difficult.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to overcome various problems in the conventional deposited film forming apparatus by the microwave plasma CVD method as described above, and to provide a semiconductor device, a photoconductor device for electrophotography, By using microwave plasma CVD method, a deposited film with good characteristics can be formed inexpensively, stably, and with good yield as a line sensor for image input, image pickup device, photovoltaic device, other various electronic elements, and element members used for optical elements. An object is to provide a deposited film forming apparatus which can be obtained.

An object of the present invention is to provide a deposition film forming apparatus capable of forming a high quality deposition film at a high speed by a microwave plasma CVD method, especially when forming a relatively thick amorphous silicon deposition film of 10 microns or more. is there.

[0016]

According to the present invention, a plurality of cylindrical substrates are arranged in the reaction container so as to surround the discharge space in a reaction container capable of being decompressed, and a gaseous state is formed in the discharge space in the reaction container. A gas discharge nozzle for introducing the raw material is provided, and means for introducing microwave energy is provided so as to oppose the discharge space formed by the cylindrical substrate at two positions in the generatrix direction. In the deposited film forming apparatus, which is provided with a means for applying a bias voltage to the cylindrical substrate, a gas pipe for guiding a gaseous raw material to the gas emission nozzle is connected to the gas emission nozzle. A deposition film forming apparatus characterized in that a gas pipe has a vertically symmetrical shape in a discharge space.

In the deposited film forming apparatus of the present invention, the gas discharge nozzle and the gas pipe may be made of an electrically conductive material, and the gas discharge nozzle is surrounded by the substrate in the center of the discharge space. You can place it in

[0018]

The inventors of the present invention have made extensive studies to overcome the above problems in the conventional deposited film forming apparatus and achieve the object of the present invention, and have obtained the following findings.

Conventional microwave plasma CV shown in FIG.
In the case of a deposition apparatus in which a gas emission nozzle is arranged in the discharge space, such as a deposition film forming apparatus by the D method, a gas pipe 5 that is connected to the gas emission nozzle 508 and guides a gaseous source material
12 (hereinafter, this gas pipe is referred to as "branch pipe") is an essential constituent requirement. In this conventional deposition film forming apparatus, the cylindrical substrates 505 are arranged concentrically, and microwave power is introduced from above and below the space surrounded by these cylindrical substrates via the waveguide 503. At this time, in order to form a uniform deposited film in the generatrix direction of the cylindrical substrate, the gas discharge nozzle 508 is for depositing the film parallel to the generatrix direction of the cylindrical substrate and uniformly on all of the plurality of cylindrical substrates. It was necessary to install in the center of the discharge space. For this reason, the branch pipe 512 to supply the gas to the gas discharge nozzle arranged in the center of the discharge space has to be asymmetric in the discharge space.

On the other hand, when a deposited film is formed on a large-area cylindrical substrate such as an electrophotographic photosensitive member, it is important to suppress variations in characteristics of each part in order to suppress unevenness in image density. In particular, in the deposited film forming apparatus having a structure in which microwave power is input from above and below the cylindrical substrate shown in FIG. 5, characteristic unevenness in the bus line direction becomes a problem. One way to prevent such characteristic unevenness in the busbar direction is to make the structure in the reactor vertically symmetrical so that the flow of raw material gas and the distribution of microwave power are not vertically asymmetrical. is important.

However, the conventional branch pipe has an asymmetric shape in the vertical direction as described above. For this reason, among the photoconductors that are manufactured in a single film formation process, the optimum film formation conditions may deviate between the photoconductors that are not adjacent to the branch pipe and the photoconductors that are adjacent to each other. There was something. As a result, when the film formation parameters are set for the photoconductors that are not adjacent to the branch pipes under conditions that the characteristics in the busbar direction are good, the photoconductors adjacent to the branch pipes show a change in the characteristics in the busbar direction. ,
Depending on the film-forming conditions, the photoconductor often cannot be put to practical use. On the contrary, if the optimum film forming parameters are set for the photoconductor adjacent to the branch pipe,
On the contrary, in some cases, a defect may occur with respect to the photoconductors that are not adjacent to each other. Therefore, from these trade-offs, it is necessary to compromise the film forming conditions where the two properties are compatible with each other to some extent. Therefore, avoid an unstable situation where a slight deviation or fluctuation of the conditions greatly affects the non-defective product rate. I couldn't.

The influence of this branch tube brings about unevenness in surface potential such as charging ability and residual potential in the electrophotographic photosensitive member. Especially, unevenness in density due to variation in halftone potential makes it possible to achieve high image quality in recent years. Has become a very problematic machine.

The following points can be considered as the cause of the nonuniformity in the bus line direction. In the cylindrical substrate adjacent to the branch pipe, the flow of the raw material gas is different from that of the cylindrical substrate in other positions. Generally, in the region adjacent to the branch pipe, the gas flow becomes poor, so that the deposition rate decreases and the film thickness decreases. Therefore, in a device such as an electrophotographic photosensitive member that requires a thick film, the electrical characteristics of the region adjacent to the branch pipe deteriorates. When the gas discharge nozzle is installed in the center of the discharge space, a part of the branch pipe always crosses just before the microwave introduction window. Since at least a part of the branch pipe is made of a conductor for applying a bias voltage, it forms a microwave reflecting surface. Therefore, a difference in impedance is generated between the side where the branch pipe crosses and the side where the branch pipe does not exist, which causes unevenness in the bus-line direction.

For the above two reasons, the photoconductor adjacent to the branch pipe is more likely to deteriorate in characteristics in the generatrix direction than the photoconductor not adjacent to the branch pipe. The irregularity in the bus-line direction may be deteriorated to the extent that it cannot be provided.

From the above research results, in order to make the characteristics of the photoconductor adjacent to the branch pipe uniform in the generatrix direction, it is the most technically and costly to make the branch pipe vertically symmetrical. We have come to the conclusion that it is an effective solution.
That is, since the flow of the source gas through the branch pipe is symmetrical in the vertical direction, the deposition rate becomes uniform in the generatrix direction, and the film thickness unevenness is eliminated. Further, since the types and amounts of active species are also uniform, there is no unevenness in terms of film quality. By using a vertically symmetrical branch pipe, the arrangement of the structures inside the furnace as seen from the upper and lower microwave introduction windows will be the same, and the upper and lower impedances will match. For this reason, the microwave introduction efficiency is matched vertically, the energy given to the raw material gas is made uniform, and the distribution of the type and amount of active species is also made uniform so that the film quality is uniform and electrical unevenness in the busbar direction is reduced. To do. That's what it means. In this case, since it is the plasma state that must be vertically symmetrical, the effect of the present invention can be obtained if the branch tube is symmetrical only in the discharge space.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a gas supply means comprising a gas discharge nozzle and a connecting branch pipe thereof suitable for use in the deposited film forming apparatus of the present invention will be explained.

FIG. 2 shows one specific example of the gas supply means of the present invention. In this example, the branch pipe 201 is the gas discharge nozzle 2
00, and is connected to a gas introduction port 204 provided in the upper part of the reaction vessel. A symmetrical branch according to the present invention is shown at 202, and the discharge space 2
In 07, it is symmetrical with the branch pipe 201. Branch pipe 202
The source gas 206 is supplied to the gas discharge nozzle 200 from outside the reaction vessel, and a bias voltage is supplied from the bias power source 205.

In the symmetrical branch pipe according to the present invention, since the portion A arranged in parallel with the gas discharge nozzle extends over the entire length of the gas discharge nozzle, the upper half of the photosensitive drum adjacent to the branch pipe is The flow rate of the raw material gas and decomposed species in the lower half can be made uniform, and the deposition rate can be made uniform.
It has the effect of making the film quality uniform.

FIG. 3 shows another specific example of another gas supply means of the present invention. In this example, the branch pipe 301 is connected to the upper end of the gas discharge nozzle 300. A symmetrical branch according to the present invention is shown at 302, and the discharge space 307
Inside, it is symmetrical with the branch pipe 301. In this case,
Unlike the specific example of No. 1, there is no portion A parallel to the gas discharge nozzle 300. However, there is a portion B that crosses the waveguide 303 and forms a reflecting surface. In this case, the role of the symmetrical branch tube 302 is to form an equivalent reflecting surface exclusively for the upper and lower waveguides 303 and to perform upper and lower impedance matching.

FIG. 4 shows still another specific example of the gas supply means of the present invention. In this specific example, the branch pipe 401 is connected to the center of the gas discharge nozzle 400, and is connected to the gas introduction port 404 provided in the upper portion of the reaction container. The branch pipe of this specific example has at the same time an A portion that runs parallel to the gas discharge nozzle and a B portion that crosses the waveguide 403.

With the symmetrical branch tube according to the invention,
Since the portion A installed in parallel with the gas discharge nozzle extends over the entire length of the gas discharge nozzle, the flow of the raw material gas and the decomposed species in the upper half and the lower half of the photosensitive drum adjacent to the branch pipe are aligned, Since the deposition rates are made uniform, there is an effect of making the film thickness and film quality uniform. In addition, the portion B that crosses the waveguide 403 and serves as a reflection surface is similarly set in the upper and lower waveguides,
As a result of equalizing the impedance matching of the upper and lower microwaves, there is an effect that the microwave power in the vertical direction is made uniform.

In any case, it is easier to obtain the effect of the present invention by arranging the material and the thickness of the symmetrical branch pipe in the vertical direction, but at least the effect of the present invention can be obtained as long as the material conducts electricity. . Further, in order to prevent the formation of a gas reservoir, it is preferable that the symmetrical branch pipe is not hollow in terms of electrical characteristics.

Another effect of the deposited film forming apparatus using the gas supply means of the present invention is that the charging ability is improved. At this time, there is no change in the residual potential, so that the contrast of the bright and dark portions is substantially improved, and it is considered that the degree of perfection as the electrophotographic photosensitive drum is further enhanced.

At present, it is difficult to clearly explain the reason for this, but by making the branch pipe of the gas discharge nozzle located at the center of the discharge space vertically symmetrical, the plasma in the vertical direction becomes uniform, and the plasma from the gas discharge nozzle becomes uniform. It is thought that this is because the unevenness of the discharged raw material gas was reduced and the latitude of the film forming parameters relating to the electrical characteristics was widened.

The above-described gas supply means constitutes an embodiment of the deposited film forming apparatus of the present invention. As a typical example thereof, an embodiment using the gas supply means shown in FIG. 2 is shown in FIG.
It is shown in (a) and FIG. 1 (b).

In FIGS. 1A and 1B, 101 is
A reaction vessel having a vacuum-tight structure. Reference numeral 102 is a dielectric window for introducing microwaves, 103 is a waveguide for transmitting microwave power, and the dielectric window 102 is a cylindrical shape of the waveguide 103 for maintaining the atmosphere in the reaction vessel. The inner wall of the part is hermetically sealed. An exhaust pipe 104 has one end opening into the reaction vessel 101 and the other end communicating with an exhaust device. Reference numeral 105 denotes a cylindrical substrate on which a deposited film is formed. As shown in FIG. 1B, six concentric circular substrates are arranged, and each substrate is connected to a motor 110 via a rotary shaft 109.
To rotate by. Further, the waveguides 103 are provided above and below the discharge space 106 surrounded by the cylindrical substrate 105 so as to face each other, and microwave power is introduced. Reference numeral 108 denotes a gas discharge nozzle, which is arranged in the center of the discharge space 106 surrounded by the cylindrical substrate 105.
Further, a branch pipe 112 and a symmetrical branch pipe 113 are arranged symmetrically in the center of the gas discharge nozzle 108. Branch pipe 112
The source gas is supplied from outside the reaction vessel 101 to the gas discharge nozzle 108, and further, a bias voltage is supplied from the bias power supply 111.

An example of actually forming a deposited film by the deposited film forming apparatus of the present invention will be described below.

First, the reaction container 101 is evacuated through the exhaust pipe 104 by a vacuum pump (not shown), and the reaction container 1
The pressure in 01 is adjusted to 1 × 10 ⁻⁶ Torr or less. Then, the heater 107 heats and holds the temperature of the substrate 105 to an optimum temperature for drum formation. Therefore, a raw material gas such as a silane gas as a raw material gas for amorphous silicon and a raw material gas such as hydrogen gas as a diluent gas are introduced into the reaction vessel 101 through the gas discharge nozzle 108. At the same time, a microwave power source (not shown) is used to generate microwaves having a frequency of 2.45 GHz, and the waveguide 103
Is introduced into the reaction vessel 101 through the dielectric window 102. Further, a bias power source 111 electrically connected to the branch pipe 112 is used to connect the gas discharge nozzle 108 to the substrate 105.
DC voltage is applied to. Thus, in the discharge space 106 surrounded by the substrate 105, the source gas is excited by the energy of microwaves and dissociated, and the electric field between the gas discharge nozzle 108 and the substrate 105 causes the ion bombardment to the substrate 105 constantly. While receiving the deposit, a deposited film is formed on the surface of the base 105. At this time, the rotating shaft 109 on which the substrate 105 is installed is rotated by the motor 110, and the substrate 105 is rotated about the central axis in the substrate generatrix direction, whereby a deposited film is formed uniformly over the entire circumference of the substrate 105. It

The shape of the gas discharging nozzle is not particularly limited, but if there is a sharp edge portion, the deposited film adhered to the outside will peel off, so in the present invention, a cylindrical shape or a similar shape is optimal. When the diameter of the cross section is large, the surface area of the portion where the deposited film is formed on the outside of the gas pipe is large and the utilization efficiency of the raw material gas is reduced. Therefore, the diameter of the discharge space is 1% or more and 30% or less. It is preferable that
In particular, it is more preferable to set it to 3% or more and 20% or less. At this time, the diameter of the discharge space means the average of the distances from the center of the discharge space to the surfaces of all the substrates exposed to the discharge.

The length of the gas discharge nozzle is not particularly limited, but is equal to that of the cylindrical substrate or 9 of the cylindrical substrate.
The length is preferably 0% or more and 110% or less.

The materials for the gas discharge nozzle and the branch pipe are as follows:
Any material may be used as long as it has a conductive surface and can withstand high temperatures, for example, stainless steel, Ni, Al, Cr, Mo, A.
In the present invention, metals such as u, In, Nb, Te, V, Ti, Pt, Pd, and Fe, alloys thereof, glass whose surface is electrically conductive, and ceramics are usually used.

The gas discharge hole of the gas discharge nozzle preferably has a plurality of directions of discharge, and preferably faces the direction of the cylindrical substrate or the gap between the cylindrical substrates. Good. Further, it is suitable that it is oriented in a direction that spreads over the entire discharge space.

Although the shape of the gas discharge hole of the gas discharge nozzle may be any shape, a circular shape is preferable for practical use because of ease of manufacture. If the size of the gas release hole is small, it will be blocked during the formation of the deposited film, and if it is large, the pressure difference between the inside and outside of the gas release nozzle cannot be secured, and the uniformity of the thickness of the deposited film in the vertical direction of the substrate will be reduced. It is preferably 0.4 mm ² or more and 2.5 mm ² or less. Further optimally, 0.6 mm ² or more and 1.5 mm ² or less are preferable. The density of gas release holes is 0.2 / cm ²
It is preferably 2 pieces / cm ² or less.

The position on the plane of the gas discharge nozzle is such that the distance from the center of the discharge space to the center of the gas discharge nozzle is
20% of the shortest distance from the center of the discharge space to the cylindrical substrate
It may be set at any position within the range, but it is desirable to set it at the center position of the discharge space.

The number of gas discharge nozzles is not particularly limited to one as long as it does not disturb the discharge.
It is also possible to install a plurality according to the purpose. In this case, it is practically preferable that the number is 10 or less.

The heating method for the cylindrical substrate in the present invention is as follows:
Any heating element that has a vacuum specification may be used, and more specifically, electric resistance heating elements such as wound heaters of sheath heaters, plate heaters, ceramics heaters, heat radiation lamp heating elements such as halogen lamps, infrared lamps, and liquids. An example is a heating element using a heat exchange means with a gas or the like as a heating medium.
As the surface material of the heating means, metals such as stainless steel, nickel, aluminum and copper, ceramics, heat resistant polymer resin and the like can be used. In addition to this, it is also possible to use a method in which a container dedicated to heating is provided in addition to the reaction container, and after heating, the substrate is conveyed into the reaction container in a vacuum. Furthermore, in combination with these means or alone,
It is also possible to control the substrate temperature by the microwave itself used for the discharge (for example, by changing the intensity as needed).

In the present invention, the source gas for the deposited film is
For example, amorphous silicon forming raw material gas such as silane (SiH ₄ ), disilane (Si ₂ H ₆ ), germane (Ge)
Other functional deposition film forming raw material gases such as H ₄ ), methane (CH ₄ ) and the like, or a mixed gas thereof can be used.

Examples of the diluent gas include hydrogen (H ₂ ), argon (Ar), helium (He) and the like.

Further, the band gap width of the deposited film is changed.
Ammonia (NH₃ ),
Elementary (N₂ ) And other elements containing a nitrogen atom, oxygen (O₂ ),acid
Nitric oxide (NO), dinitrogen oxide (N₂ O) and other oxygen atoms
Element containing, methane (CH_Four ), Ethane (C₂ H₆ ), D
Chiren (C₂ H_Four ), Acetylene (C₂ H₂ ), Prop
(C₃ H₈ ) And other hydrocarbons, silicon tetrafluoride (SiF
_Four ), Silicon hexafluoride (Si ₂ F₆ ), Germanium tetrafluoride
Mu (GeF_Four ) And other fluorine compounds or mixed gases of these
Can be mentioned.

For the purpose of doping, diborane (B ₂ H
_6), fluoride boron (BF _3), phosphine (PH ₃₎
The present invention is similarly effective even if a dopant gas such as is introduced into the discharge space at the same time.

In the present invention, the material of the dielectric window for introducing microwaves is alumina (Al ₂ O ₃ ), aluminum nitride (AlN), boron nitride (BN), silicon nitride (SiN), silicon carbide. (SiC), silicon oxide (SiO
₂ ), beryllium oxide (BeO), Teflon, polystyrene, and other materials with low microwave loss are usually used.

In the present invention, the effect was exhibited in any region of the pressure of the discharge space, but in particular, 100 mTorr or less,
Particularly preferable results were reproducibly obtained at 50 mTorr or less.

Examples of the cylindrical substrate material include stainless steel, Al, Cr, Mo, Au, In, Nb, Te,
Metals such as V, Ti, Pt, Pd, and Fe, alloys of these, synthetic resins such as polycarbonate whose surface is subjected to conductive treatment, glass, ceramics, paper, and the like are usually used in the present invention.

The size of the cylindrical substrate is not particularly limited, but practically it is 20 mm or more and 500 mm or less in diameter and 1 in length.
It is preferably from 00 mm to 1000 mm.

The interval between the cylindrical substrates is 1 mm or more and 50 mm
The following are preferred. The number of bases may be any as long as a discharge space can be formed, but 3 or more, and more preferably 4 or more are suitable.

Furthermore, the present invention relates to a blocking type amorphous silicon photoconductor, a high resistance type amorphous silicon photoconductor, etc.
It can also be applied to the production of photoconductors for copying machines or printers.

A cylindrical substrate is provided so as to surround the discharge space,
This has a great effect on an apparatus having a structure in which a microwave is introduced from at least one end side of the cylindrical substrate by a waveguide.

The results of experiments using the deposited film forming apparatus of the embodiment will be described below, but the present invention is not limited to these.

[Experimental Example 1] FIG. 1A and FIG.
The gas supply means according to the present invention shown in FIG. 2 is installed in the deposited film forming apparatus shown in (b), and the charge injection blocking layer, the photosensitive layer, and the surface layer are arranged from the bottom under the conditions shown in Table 1 in the film forming method. A layered amorphous silicon electrophotographic photoreceptor was prepared. The number of electrophotographic photosensitive members produced by one-time film formation is 6, and the charging ability, the residual potential, the unevenness of the halftone potential in the bus line direction, and the contrast potential (= charging ability-
The residual potential) was measured by mounting it on our product NP6650 modified for experiments. The methods for evaluating the chargeability, residual potential and halftone potential are as follows.

[0060]

[Table 1] Charging ability: A photoconductor on which a deposited film is formed is mounted on a copying machine, and the surface potential of the dark portion of the photoconductor under a constant charging current is measured at the developing device position while rotating the photoconductor.

Residual potential: The photoreceptor is charged so as to have a constant dark part surface potential, and image exposure is immediately performed. A xenon lamp is used as a light source, and a filter is used for 550
A certain amount of light excluding light in the wavelength range of nm or less was irradiated. The surface potential at this time is measured.

Halftone potential: The amount of light at which the surface potential of the photoconductor becomes 50 V is found by the same procedure as the residual potential.
The surface potential at the time of irradiating 1/2 of this light amount is measured.

The unevenness is defined by the difference between the maximum value and the minimum value of the surface potential of the image portion in the bus line direction, and is classified into the following ranks.

∘: very good ∘: good Δ: no problem in practical use ×: trouble in practical use Further, the film thickness in the generatrix direction of each photosensitive member was measured. The average value of the values measured at three points in the circumferential direction was taken as the film thickness, and the film thickness was measured in steps of 1 cm. The evaluation of unevenness was defined by the difference between the maximum value and the minimum value of the film thickness, and classified into the following ranks.

∘: 2 μm or less ∘: 2-3 μm Δ: 3-4 μm x: 4 μm or more Evaluation results are shown in Table 2. Here, the "position in the reaction vessel" in the table indicates the position in Fig. 1 (b). When the gas discharge nozzle having the symmetrical branch pipe of the present invention is used, the unevenness of the bus bar is not deteriorated even in the photoconductor adjacent to the branch pipe.

[0066]

[Table 2] [Comparative Example 1] Under the conditions shown in Table 1 in the above-described film forming method, the charge injection blocking layer, the photosensitive layer, and the surface layer were formed from the bottom of the three layers in the deposition film forming apparatus equipped with the conventional gas supply means shown in FIG. An amorphous silicon electrophotographic photoreceptor was prepared as follows. The number of electrophotographic photosensitive members produced by one-time film formation was 6, and the charging ability, the residual potential, the unevenness of the halftone potential in the generatrix direction, and the contrast potential were measured for each.
Further, the film thickness unevenness in the bus bar direction was also measured. The evaluation method was the same as in Experimental Example 1. The results are shown in Table 3. Here, the position in the reaction vessel is shown as in Experimental Example 1. The irregularity of the bus bar of the photoconductor adjacent to the branch pipe is aggravated.

Regarding the contrast potential, Experimental Example 1 is improved as compared with Comparative Example 1.

[0068]

[Table 3] [Experimental Example 2] The gas supply means according to the present invention shown in FIG. 3 was installed in the deposited film forming apparatus shown in FIGS. 1A and 1B, and the film forming method was performed under the conditions shown in Table 1. From the bottom, an amorphous silicon electrophotographic photoreceptor comprising three layers of a charge injection blocking layer, a photosensitive layer and a surface layer was prepared. There are 6 electrophotographic photoconductors that can be produced by one film formation, and the chargeability, residual potential, unevenness of the halftone potential in the busbar direction, and the contrast potential are modified from our product NP6650 for experiments. It was attached to and measured. Further, the film thickness unevenness in the bus bar direction was also measured. The measurement method was the same as in Experimental Example 1.

The evaluation results are shown in Table 4. When the gas discharge nozzle having the symmetrical branch pipe of the present invention is used, the unevenness of the bus bar is not deteriorated even in the photoconductor adjacent to the branch pipe.

[0070]

[Table 4] [Comparative Example 2] The conventional deposition film forming apparatus shown in FIG. 5 was provided with the conventional gas supply means shown in FIG.
Under the conditions shown in (1), an amorphous silicon electrophotographic photoreceptor including a charge injection blocking layer, a photosensitive layer and a surface layer was prepared from the bottom. The number of electrophotographic photosensitive members produced by one-time film formation was 6, and the charging ability, the residual potential, the unevenness of the halftone potential in the generatrix direction, and the contrast potential were measured for each. Further, the film thickness unevenness in the bus bar direction was also measured. The evaluation method was the same as in Experimental Example 1. The results are shown in Table 5.
In the table, the position in the reaction vessel is shown as in Experimental Example 1. The irregularity of the bus bar of the photoconductor adjacent to the branch pipe is aggravated.

Regarding the contrast potential, the improvement in Experimental Example 2 is recognized in comparison with Comparative Example 2.

[0072]

[Table 5] [Experimental Example 3] The gas supply means according to the present invention shown in FIG. 4 was installed in the deposited film forming apparatus shown in FIGS. 1A and 1B, and the film forming method was performed under the conditions shown in Table 1. From the bottom, an amorphous silicon electrophotographic photoreceptor comprising three layers of a charge injection blocking layer, a photosensitive layer and a surface layer was prepared. There are 6 electrophotographic photoconductors that can be produced by one film formation, and the chargeability, residual potential, unevenness of the halftone potential in the busbar direction, and the contrast potential are modified from our product NP6650 for experiments. It was attached to and measured. Further, the film thickness unevenness in the bus bar direction was also measured. The measurement method was the same as in Experimental Example 1.

Table 6 shows the evaluation results. When the gas discharge nozzle having the symmetrical branch pipe of the present invention is used, the unevenness of the bus bar is not deteriorated even in the photoconductor adjacent to the branch pipe.

[0074]

[Table 6] [Comparative Example 3] The conventional gas supply means shown in FIG. 7 was installed in the conventional deposited film forming apparatus shown in FIG.
Under the conditions shown in (1), an amorphous silicon electrophotographic photoreceptor including a charge injection blocking layer, a photosensitive layer and a surface layer was prepared from the bottom. The number of electrophotographic photosensitive members produced by one-time film formation was 6, and the charging ability, the residual potential, the unevenness of the halftone potential in the generatrix direction, and the contrast potential were measured for each. Further, the film thickness unevenness in the bus bar direction was also measured. The evaluation method was the same as in Experimental Example 1. The results are shown in Table 7.
In the table, the position in the reaction vessel is shown as in Experimental Example 1. The irregularity of the bus bar of the photoconductor adjacent to the branch pipe is aggravated.

Regarding the contrast potential, Experimental Example 3 shows an improvement over Comparative Example 3.

[0076]

[Table 7] [Experimental Example 4] The gas supply means according to the present invention shown in FIG. 4 was installed in the deposition film forming apparatus shown in FIGS. 1A and 1B, and the film forming method was performed under the conditions shown in Table 8. From the bottom, a function-separated amorphous silicon electrophotographic photosensitive member comprising a charge transport layer, a charge generation layer, and a surface layer was prepared.
The number of electrophotographic photoreceptors produced by one film formation is 6,
The chargeability, the residual potential, the halftone potential, the unevenness of the film thickness in the bus line direction, and the contrast potential for each of them are shown in Experimental Example 1.
When evaluated in the same manner as in Example 1, all of the six photosensitive members obtained were very good in terms of unevenness of the bus bar, as in Experimental Example 1. Further, a photoconductor having a good contrast potential was obtained.

[0077]

[Table 8] [Experimental Example 5] The gas supply means according to the present invention shown in FIG. 4 was installed in the deposition film forming apparatus shown in FIGS. 1A and 1B, and the film forming method was performed under the conditions shown in Table 9. From the bottom, an all-layer change type amorphous silicon electrophotographic photoreceptor comprising a photosensitive layer and a surface layer was prepared. Six electrophotographic photoconductors were formed by one-time film formation, and the chargeability, residual potential, halftone potential, unevenness of the film thickness in the generatrix direction, and contrast potential were evaluated in the same manner as in Experimental Example 1. As a result, as in the case of Experimental Example 1, all of the six photosensitive members had very good unevenness of the bus bar. Further, a photoconductor having a good contrast potential was obtained.

[0078]

[Table 9]

[0079]

EFFECTS OF THE INVENTION In a deposited film forming apparatus in which cylindrical bases are arranged concentrically and microwave power is input from above and below a discharge space surrounded by the cylindrical bases, the present invention is such that the branch pipes of gas discharge nozzles are vertically symmetrical. By this, it becomes possible to obtain a uniform film thickness and film quality at every position of the cylindrical substrate. Particularly in a device using a comparatively large cylindrical substrate such as an electrophotographic photosensitive member, the electrical characteristics in the busbar direction can be made uniform.

In particular, in the case of a photoconductor which is close to a conventional branch pipe, a slight deviation of the film forming parameter may cause unevenness in the generatrix direction to the extent that it cannot be practically used, and the non-defective rate may be deteriorated. By using the deposition apparatus of the present invention, it is possible to improve unevenness in the generatrix direction of the photoconductor adjacent to the branch pipe, widen the latitude of film forming parameters, and improve the yield rate.

As a further effect, according to the deposited film forming apparatus of the present invention, the charging ability can be improved without increasing the residual potential, the perfection of the electrophotographic photosensitive member can be further enhanced, and the electrophotographic photosensitive member can be manufactured. The latitude spreads and the rate of non-defective products can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view (a) and an AA sectional view (b) of a deposited film forming apparatus that is an embodiment of the present invention.

FIG. 2 is a detailed view of a gas supply unit in the deposited film forming apparatus of the present invention.

FIG. 3 is a detailed view of gas supply means in the deposited film forming apparatus of the present invention.

FIG. 4 is a detailed view of gas supply means in the deposited film forming apparatus of the present invention.

FIG. 5 is a sectional view of a conventional deposited film forming apparatus.

FIG. 6 is a detailed view of a gas supply unit in a conventional deposited film forming apparatus.

FIG. 7 is a detailed view of a gas supply unit in a conventional deposited film forming apparatus.

[Explanation of symbols]

101,501 Reaction container 102,502 Dielectric window 103,503 Waveguide 104,504 Exhaust pipe 105,505 Base substrate 106,506 Discharge space 107,507 Heater 108,508 Gas discharge nozzle 109,509 Rotation shaft 110,510 Motor 111,511 Bias power supply 112,512 Branch pipe 200,300,400,600,700 Gas discharge nozzle 201,301,401,601,701 Branch pipe 202,302,402 Symmetrical branch pipe 203,303,403,603, 703 Waveguide 204, 304, 404 Gas inlet 205, 305, 405 Bias power supply 206, 306, 406 Raw material gas 207, 307, 407 Discharge space 208, 308, 408 Substrate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 5/08 360 H01L 21/31

Claims (5)

[Claims] 1. A plurality of cylindrical substrates are arranged in a reaction vessel capable of reducing the pressure so as to surround the discharge space, and a gas discharge nozzle for introducing a gaseous raw material into the discharge space is installed. A means for introducing microwave energy was provided from two ends of the discharge space formed by the cylindrical substrate so as to face each other, and a means for applying a bias voltage was provided between the gas discharge nozzle and the cylindrical substrate. A deposited film forming apparatus, wherein a gas pipe for guiding a gaseous raw material to the gas discharge nozzle is connected to the gas discharge nozzle, and the gas pipe has a substantially vertically symmetrical shape in a discharge space. A deposited film forming apparatus characterized by: 2. The deposited film forming apparatus according to claim 1, wherein the cylindrical substrate has a rotating means. 3. The deposited film forming apparatus according to claim 1, wherein the gas discharge nozzle is arranged at the center of a discharge space surrounded by the cylindrical substrate. 4. The deposited film forming apparatus according to claim 1, wherein the gas discharge nozzle and the gas pipe are made of a conductive material. 5. The deposited film forming apparatus according to claim 1, which is used for manufacturing an amorphous silicon electrophotographic photosensitive member.