JPS59104468A - Formation of deposited film by plasma cvd - Google Patents

Abstract

PURPOSE:To form a uniform deposited film on a substrate with a high yield ratio at a low cost, by forming plasma while discharging raw material gas through the holes of a plurality of secondary electrodes vertically provided around the first cylindrical electrode in a diposition tank. CONSTITUTION:A cylindrical substrate 3 as an inner electrode is provided inside a vacuum chamber 1 as a deposition tank, and outer electrodes 2 comprising a plurality of pipes are provided in parallel with the axis of said inner electrode 3 on the circumference about said axis as a center. The interior of said chamber 1 is evacuated by an exhaust system 8, the substrate 3 is heated at a predetermined temp. by a built-in heater 10 and rotated by the driving of a motor 7, and plasma is formed by glow discharge between both of the electrodes 2 and 3 with a high-frequency generator 5 while discharging raw material gas containing silane, etc. introduced through a supply pipe 4 for raw material gas through many holes 11 provided at said outer electrodes 2. Hence, silicon-contg. solid matter is deposited on the substrate 3 by the decomposition of said raw material gas to form the film.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a functional film by so-called plasma CVD, and more specifically, the present invention relates to a method for producing a functional film by so-called plasma CVD. The present invention relates to improvements in methods for making H.

Amorphous silicon (hereinafter abbreviated as A-5I) whose dangling bonds are modified with a monovalent element is suitable for use as an electrophotographic photoreceptor due to its excellent photoconductivity, abrasion resistance, and heat resistance. It is expected. In addition, a-Si has almost no problems regarding the hygiene of the raw material during its production, and in addition, the fact that it is easy to increase the area of the photoreceptor is cited as an advantage for its use.

However, the dark resistance of a-5i is too low to be used alone as an electrophotographic photoreceptor, and a blocking layer is provided to prevent loads from entering the base tram 87. , this problem is solved by doping with additives. In addition, since an oxide film (Sing) tends to naturally form on the a-5i surface blood under the environment where electrophotographic equipment is normally placed, its surface has a high affinity for water, and this condition causes corona discharge. When using an electrophotographic process that makes extensive use of
This results in what is commonly called a blurred image. To prevent this, SiNx, 5iCx, etc. are often provided as a surface protective layer, and furthermore, an antireflection layer, a light absorbing layer, a sparrow adhesion layer, etc. are often provided depending on the necessary yellowing.

In order to put the a-5i into practical use as an electrophotographic photoreceptor, it is necessary to use a variety of gases to form a photoconductive member with a multilayer structure suitable for the purpose into a size that can be used as an electrophotographic photoreceptor. Must. In this case, the uniformity of the photoconductive member is extremely costly, and if defects such as pinholes are present, it is not only impossible to provide a beautiful image, but also impractical.

゛When using a-Si as a photographic photoreceptor, environmental fluctuations and 1'[i: Considering the stability of the secondary photographic device, etc., a film thickness of 110 μs or more is required in order to obtain sufficient alignment and consistently obtain good images. For this reason, the amount of gas required to manufacture the photoconductor tram is not at all small, and in addition, 1! father 1
In order to achieve this, it is said that it is preferable to increase the flow rate of waste while decreasing the active ratio of photoconductivity +ld. Historically, the electricity and labor costs required for plasma discharge are not small, and the cost per drum is considerably higher than that of other photosensitive and photosensitive materials. Therefore, the low manufacturing yield is one of the major obstacles to practical application.

Conventionally, methods proposed for manufacturing electrophotographic photosensitive drums using plasma CVD are broadly classified into inductively coupled types and capacitively coupled types.

In the former method, a coil is arranged to surround the drum base, high-frequency power is fed to the coil, gas is turned into plasma by electromagnetic energy, and a film is formed on the base. However, the coil diameter, spacing, etc. Discharge unevenness due to misalignment and standing waves in the coil is likely to occur, and the formed film will have non-uniform thickness and electrical properties.

On the other hand, the latter type uses double coaxial cylindrical electrodes using the drum base itself as the internal electrode inside a cylindrical deposition tank that also serves as the external electrode. A DC or AC electric field between the electric power U
However, gas plasma is formed by the glow discharge at this time, and the deposited film is formed on the body.This method is good for film formation except for the cylindrical end as long as the discharge is stable. It can be done.In order to perform the market stably, it is better to feed high frequency power than to apply direct current.To prevent uneven discharge at the end of the cylinder, install a comb at both ends of the base drum. However, there are problems such as disturbances in glow discharge due to the presence of a raw material gas supply pipe installed between the two electrodes or gas being supplied from this raw material gas supply pipe during discharge. there were.

a-Si is I+! ,! It is known that the morphology of is greatly influenced by the substrate shape. In other words, in the case of large-area electrophotographic photoreceptors that require almost the same electrical characteristics in most places, the surface condition of the substrate is extremely important, and the presence of irregularities on the substrate surface can cause the film to deteriorate. The uniformity deteriorates and columnar structures and spherical protrusions are formed, which causes electrical non-uniformity.

However, when the above-mentioned discharge disturbance occurs, the concentration of gas plasma, radicals, or ions in the vicinity of the drum base, which is the internal electrode, changes greatly from the steady state.
For example, crystal nuclei or island-like structures are formed on the drum substrate, and even if the overall discharge stability is excellent, the resulting photoconductive film is non-uniform. Put it away. In addition, gas molecules, ions, or radicals that have obtained significantly large amounts of energy due to abnormal discharge may attack the surface of the substrate, creating irregularities on the substrate, making it difficult to obtain a uniform film.

Furthermore, if photoconductor drums are manufactured using the conventional double coaxial cylindrical electrode method, the photoconductor drum itself is quite large, so the external electrodes or deposition tank used for it are quite large, and high performance is required. In order to form a deposited film, it is necessary to keep these internal surfaces clean at all times, and cleaning is essential for this purpose. Therefore, it is also required that the apparatus used in such a method of forming a deposited film be easy to clean.

The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a novel method for forming a deposited H component that solves the second problem.

Another object of the present invention is to produce a photoconductive film for electrophotographic photoreceptors, which has excellent electrical properties and environmental stability and can provide good images over the entire area of the photoreceptor, at low cost and with high sand retention. The goal is to provide a way to do so.

Yet another object of the present invention is to provide a deposited film in a well-formed manner without requiring easy cleaning of the interior of the deposition tank.

The object of the present invention is to stabilize the discharge during film formation by using a plurality of cylindrical pipes as external electrodes and releasing the raw material gas into the deposition tank from the raw material gas discharge holes provided in the cylindrical pipes. It was found that this can be achieved by increasing gender.

That is, the present invention generates a discharge between a first electrode and a second electrode installed in a deposition tank, and converts a solid containing silicon into a substrate from a gas introduced into the deposition tank by this discharge. In the method of forming a film by depositing on the first electrode, the first electrode has a cylindrical shape, and the second electrode has a cylindrical shape.
A plurality of pipes are arranged on a circumference centered on the axis of the electrode and are substantially parallel to the axis, and the gas is introduced into the deposition tank through one or more holes provided in the - part or all of the pipes. This is a method of forming a deposited film characterized by the release of the film.

Hereinafter, the method of the present invention will be explained in detail with reference to the drawings.

Reference numeral 1 designates a vacuum chamber, and a cylindrical base 3 on which a deposited layer is formed is installed at the center of this chamber, and this serves as a second electrode (hereinafter referred to as an internal electrode) as an electrode. The first electrode (hereinafter referred to as the external electrode) as a cathode electrode of the pipe 2 which also serves as the waste introduction pipe is connected to the central axis of the internal electrode on a circumference centered on the central axis of the internal electrode. Multiple pieces are installed approximately parallel to each other at approximately equal intervals.

In this example, the internal electrodes match the photoreceptor drum substrate, but this does not necessarily have to be the case.

When using this device to form a deposited layer on a cylindrical substrate 3, first place a circular 1.5-shaped hole in the vacuum chamber 1 (the body 3 is centered, and the υ1 gas system 8 is activated). The inside of the chamber is evacuated.Generally, a rotary pump, mechanical booster pump, diffusion pump, or a combination thereof is used for the exhaust system, depending on the desired degree of vacuum and productivity.At the same time, the substrate 3
is heated using heaters 9-10, and the base body 3 is rotated by the motor 7 at a rate of once every several to several tens of seconds, thereby making the temperature distribution of the body ξ uniform. Circle f4 shaped glue,
(To control the temperature of the body 3, a control system is usually used that uses a heater placed inside the internal electrode and a temperature sensor, such as a thermocouple, installed at or near the internal electrode 3. The temperature is maintained at 100 to 350° C. The gas supply pipe 4 and the vacuum chamber 1 are insulated from the external electrodes by an insulating insulator 6.

], (When the body temperature becomes constant, the gas supply pipe 4
Supplies raw material scraps from For raw material waste, a-3i
Silane (SiH, Si, H6) as a film forming material
, Si, H8, 5i4H, o, etc.), H2 as a base gas, rare gas, SiF4, P or n for introducing fluorine.
B2H6, PH3, As, H3 for conduction control, N2, NHL for nitrogen doping, N20 for oxygen doping,
NO1 Carbon Dorf.

Hydrocarbons such as CH4, 02H4, etc. are mixed in a predetermined ratio using a mass flow controller or the like with plasma CVD or various gases known as those capable of doping. Supplied accordingly. The release amount of the raw material gas fed with 0 can also be changed by adjusting the diameter and number of gas release holes drilled in the gas release pipe 2, which also serves as an external electrode. The thickness of the deposited film! 1j, adjustments can be made. The gas discharge tube 2 is usually in the shape of a cylindrical pipe, and the direction in which the gas discharge hole is installed is determined, for example, by the direction of the vacuum chamber/X-wall I.
By drilling holes in the direction of I\i, it is possible to avoid disturbances in glow discharge caused by blowing source gas directly toward the substrate and foreign matter from adhering to the surface of the substrate. The number of waste discharge pipes provided in the vacuum chamber is approximately 3 to 50, preferably 6 to 20. If the number of waste discharge pipes, which are also external electrodes, is too small, the electric field in the vacuum chamber will become uneven and abnormal discharges will easily occur.On the other hand, if the number is too large, it will be difficult to set the appropriate position of the external electrodes. This is not suitable because it causes problems such as the external electrode becoming hard to clean and requiring time and effort to clean the external electrode.

In a state where the raw material gas is stably supplied in the vacuum chamber, a high frequency voltage is applied to the external electrode 2 by the high frequency power supply 5 of 13.58 MHz, for example, and the ground S is connected to the earth 9.
A glow discharge is generated between the substrate 3 and the substrate 3, which decomposes the raw material gas in the vacuum chamber/tube 1, and deposits are appropriately deposited on the substrate 2 to form, for example, a-8i. can be used.

When a film was formed according to the method of the present invention, a steady glow discharge continued even if the type of gas was changed from time to time, and a film with high uniformity that was suitable for electrophotographic photoreceptors could be formed at a low cost. So I was able to implement it with a little effort. Also,
The external electrodes are small pipe-shaped, unlike the large cylindrical ones of the conventional coaxial double cylindrical electrode method, so they can be easily disassembled and removed for cleaning, and the inside of the vacuum chamber can be kept at all times. It was possible to keep it in a clean state and use it for forming a sediment film.

[Brief explanation of the drawing]

FIG. 1 is a schematic depiction of a deposited film forming apparatus suitable for use in the method of the present invention. 1: Vacuum puncher 2: Pipe (external electrode) 3: Substrate (internal electrode) 4: Raw material gas supply pipe 5: High frequency generator 6: Insulation insulator 7: Motor 8: Exhaust system 9: Earth 10: Heater 7 11 : Raw material gas release hole

Claims (1)

[Claims] (2) A discharge is generated between the first electrode and the second electrode installed in the deposition tank, and solids containing silicon are deposited on the substrate from the gas introduced into the deposition tank by this discharge. In the method of forming an H-hole by forming a hole, the first electrode has a cylindrical shape, and the second electrode has a plurality of electrodes arranged on a circumference centered on the axis of the first electrode and substantially parallel to the axis. (A method for forming a deposited film, characterized in that the gas is discharged into a sedimentation tank from holes arranged as a pipe with one bias and two holes provided in a part or all of the pipe.