JPS63230880A - Device for forming functional deposited film by microwave plasma cvd method - Google Patents

Abstract

PURPOSE:To steadily form a functional deposited film with high efficiency by providing a means for efficiently introducing a raw gas into a plasma producing region and a means for adjusting the exhaust in the region to a raw gas supply means. CONSTITUTION:A raw gas supply pipe 10 has the shape of a triangular pole, a comb- line raw gas injection nozzle 10' is provided to one corner of the side wall, and the tip of the nozzle is directed to the inside of the plasma producing region 9. The inside of a vacuum vessel 1 is evacuated through an exhaust pipe 5, a cylindrical base body 7 is heated by a built-in heater, and the raw gas is injected into the vessel 1 through the nozzle 10' of the supply pipe 10. A microwave 4 is introduced into the vessel 1 through a waveguide 3, etc., and a deposited film is formed on the surface of the base body 7. The raw gas injected from the tip of the nozzle 10' is diffused into the region 9 in the direction as shown by the arrow, and the diffusion amt. to the outside of the region 9 is drastically reduced. When the gas in the region 9 is discharged through the exhaust pipe 5, the exhaust gas passes through the space between the base body 7 and the supply pipe 10 while lapping the body and pipe, hence the exhaust conductance is made constant, and the concn. of the active species is fixed.

Description

Detailed Description of the Invention [Technical Field to which the Invention Pertains] The present invention relates to a film deposited on a substrate, particularly a functional film, particularly a semiconductor device, a photosensitive device for electrophotography, a line sensor for image input, an imaging device, and a photosensitive device. The present invention relates to an apparatus for forming functional deposited films such as amorphous semiconductors used in power devices and the like by microwave plasma CVD.

[Description of prior art]

Conventionally, semiconductor devices, photosensitive devices for electrophotography,
Amorphous silicon, such as amorphous silicon compensated with hydrogen or/and halogen (e.g. fluorine, chlorine, etc.), is used as an element member for image input line sensors, imaging devices, photovoltaic elements, and various other electronic elements, optical elements, etc. Silicon (rA-3i (hereinafter referred to as rA-3i)
Deposited films of amorphous semiconductors such as H, X) J) have been proposed, and some of them have been put into practical use.

Then, such a deposited film is deposited using a plasma CVD method, that is,
It is known that it is formed by a method in which raw material gas is decomposed by direct current, high frequency, microwave, or glow discharge to form an El film-like deposited film on a substrate such as glass, quartz, stainless steel, or aluminum. Various devices have also been proposed.

By the way, in recent years, the plasma CVD method using microwaves (hereinafter referred to as rMW-PCVD method) has attracted attention, and several devices for that purpose have been proposed.
Efforts have been made to produce the above-mentioned deposited film on an industrial scale by the PCVD method. Such conventionally proposed M
An apparatus using the W-PCVD method typically has an apparatus configuration shown in a perspective schematic diagram in FIG. 4.

In Fig. 4, 1 is a vacuum vessel, 2 is a dielectric window made of alumina ceramics or quartz, 3 is a waveguide for transmitting microwaves, 4 is a microwave, 5 is an exhaust pipe, and 6 is a raw material gas supply pipe. , 7 indicates a cylindrical substrate, and 8 indicates a substrate heating heater. Since the vacuum container 1 starts the discharge by self-excited discharge without using a discharge trigger etc., the oscillation of the microwave power source (not shown) is required. It is common to use a cavity resonator structure that resonates with the frequency.

Formation of a deposited film using such an apparatus is performed in the following manner. That is, the inside of the vacuum container 1 is evacuated via the exhaust pipe 5, and the cylindrical substrate 7 is heated and maintained at a predetermined temperature by the substrate heating heater 8. In the case of forming an amorphous silicon deposited film, a raw material gas such as silane gas or hydrogen gas is passed through a plurality of gas discharge holes 6', 6', . . . opened in the raw material gas supply pipe 6. It is discharged into a vacuum vessel l. At the same time, a microwave power source (not shown) generates microwaves 4 with a frequency of 500 MHz or more, preferably 2.450 H1, and the microwaves pass through the waveguide 3 and pass through the dielectric window 2. via vacuum container 1
be introduced within. In this way, the raw material gas introduced into the vacuum container is excited by the microwave energy and dissociated, producing neutral radical particles, ion particles, electrons, etc.
These react with each other to form a deposited film on the surface of the cylindrical substrate 7.

By the way, the present inventor has discovered that the above-mentioned conventional MW-PC
In order to enable mass production of a functional deposited film forming apparatus using the VD method, we have discovered that it is sufficient to arrange a plurality of cylindrical substrates in a vacuum container. FIG. 5 is a schematic perspective view showing a typical example of a device that enables such mass production.

In Figure 5, 1 is a vacuum container, 2 is alumina ceramics or quartz, etc.! A Wt body window, 3 a waveguide section for transmitting microwaves, and 4 microwaves from a microwave power source (not shown). 5 has one end opened into the vacuum container I,
An exhaust pipe whose other end communicates with an exhaust device (not shown) via an exhaust valve (not shown), 6 is a valve (not shown)
a raw material gas supply pipe communicating with a raw material gas supply source (not shown) via a cylindrical base 7 arranged concentrically;
Reference numeral 8 indicates a heater for heating the substrate, and reference numeral 9 indicates a plasma generation region g generated in the vacuum container by microwaves passing through the dielectric window 3. The plasma region 9 includes the dielectric window 2 and the base 7,
7. It has a microwave cavity resonant structure surrounded by... and efficiently absorbs the introduced microwave energy.

Formation of a deposited film using the above-mentioned apparatus is performed in the same manner as in the case using the apparatus shown in FIG.

That is, the inside of the vacuum container 1 is evacuated via the exhaust pipe 5, and the cylindrical substrates 7, 7 . ...drive motor (
) at a predetermined rotational speed, and the substrates 7, 7 . The primary raw material gas is heated and maintained at a predetermined temperature by a heater (not shown) built in the raw material gas supply pipe 6.6. A plurality of gas discharge holes 6' are opened in .

6', . . . into the vacuum container 1.

At the same time, microwaves 4 are introduced into the vacuum container via the waveguide 3 and the dielectric window 2, and the cylindrical bases 7, 7 are
．． A deposited film is formed on the surface of...

By the way, in the above-mentioned apparatus, as shown in FIG. 6, a plurality of gas discharge holes 6', 6', . Since the raw material gas supply pipe 6 is installed, when a 1 m salt film is formed by decomposing the raw material gas, the gas discharge hole 6'
, 6', . . . will be diffused outside the plasma generation region 9, as shown in FIG.
6 is a schematic cross-sectional view showing the flow of raw material gas in the apparatus shown in FIG. 5. FIG. As shown in FIG. 7, the gas release hole 6
',6', .・・・・・・
(dotted line arrow), that is, to areas other than the plasma generation region 9, the efficiency with which the raw material gas is introduced into the plasma generation region 9 decreases, and the There is a problem in that the deposition rate of the deposited film is slow and it takes a very long time to deposit it to a desired thickness.

Furthermore, as shown in FIG. 7, since the raw material gas supply pipe 6 installed between the cylindrical base bodies 7 is cylindrical, the inside of the vacuum vessel 1 is passed through the exhaust pipe 5. During evacuation, the conductance of the evacuation differs between the substrates 7 and 7, and the concentration of active species that participate in the reaction on the surface of the substrate 7 on the plasma generation region 8 side differs depending on the location.
As a result, the discharge within the plasma generation region 8 tends to become unstable, and the thickness of the deposited film formed on the substrate 7 may not be constant and its characteristics may also become non-uniform. be.

Therefore, if it is attempted to mass-produce deposited films using only such raw material gas supply pipe 6, the actual situation is that the yield will be extremely low.

[Purpose of the invention]

The present invention overcomes the above-mentioned problems in the conventional deposited film forming apparatus using the MW-PCVD method, and provides semiconductor devices, electrophotographic photoreceptor devices, image input line sensors, imaging devices, and photovoltaic devices. The purpose of the present invention is to provide an apparatus that enables constant and highly efficient formation of functional deposited films as element members used for elements, various other electronic elements, optical elements, etc. by MW-PCVD method. It is something.

That is, an object of the present invention is to make it possible to make the thickness and quality of deposited films uniform between substrates and on the same substrate in a functional deposited film forming apparatus using the MW-PCVD method,
The object of the present invention is to provide an apparatus that can regularly mass-produce high-quality deposited films.

Another object of the present invention is to efficiently mass-produce deposited films of high quality and having excellent electrical, optical, or photoconductive properties using a functional deposited film forming apparatus using the MW-PCVD method. The objective is to provide a device that can be used to

[Structure and effect of the invention]

The present inventor has conducted extensive research in order to solve the above-mentioned problems in the conventional deposited film forming apparatus using the MW-P CVD method and to achieve the object of the present invention.
Various problems in the conventional deposited film forming apparatus using the MW-P CVD method can be solved by providing a means for efficiently introducing raw material gas into the plasma generation region and a means for adjusting the exhaust air in the plasma generation region. We have found that the problem can be solved by providing a means to remove the problem. Furthermore, after further studies based on this knowledge, the present inventor found that the raw material gas supply means has two functions, namely, the function of efficiently introducing the raw material gas into the plasma generation region, and the function of efficiently introducing the raw material gas into the plasma generation region. We have found a solution to this problem by creating a shape that also has the function of adjusting the exhaust gas.

The apparatus for forming a functional deposited film using the microwave plasma method of the present invention has been completed based on the above-mentioned knowledge, and includes a sealed vacuum container and a plurality of substrates for forming functional deposited films in the vacuum container. By a microwave plasma CVD method comprising a means for holding, a means for supplying a raw material gas into the vacuum container, a means for evacuating the inside of the vacuum container, and a means for generating microwave discharge plasma in the vacuum container. An apparatus for forming functional deposited films on a plurality of substrates, wherein the raw material gas supply means has a function of efficiently introducing raw material gas into a plasma generation region and a function of adjusting exhaust gas in the plasma generation region. It is characterized by having the following.

Hereinafter, the apparatus for forming a functional deposited M1 film using the microwave plasma CVD method of the present invention will be explained in more detail with reference to the embodiments of the drawings, but the apparatus for forming a deposited film of the present invention is not limited thereto.

FIG. 1 is a perspective view schematically showing a typical example of a deposited film forming apparatus using the microwave plasma CVD method of the present invention, and in this figure, the same elements as those shown in FIG. 5 above are shown. Items with numerals indicate those having the same function, 1 is a vacuum container, and 2 is a material that can efficiently transmit microwaves into the vacuum container and maintain vacuum tightness, such as quartz. The dielectric window 3 made of glass or the like is mainly made of a metal rectangular waveguide, and has a three-pillar matching box (
A microwave waveguide 4 is connected to a microwave power source (not shown) via an isolator (not shown) and an isolator (not shown); 5 is a microwave; An exhaust pipe whose end communicates with an exhaust device (not shown), 7 a cylindrical base, 9 a plasma generation region, 10 a triangular prism-shaped source gas supply tube, and 10' a side wall of the source gas supply tube. The source gas discharge and output nozzles are shown protruding in a comb shape from one corner. FIG. 2 shows a raw material gas supply pipe I having a discharge nozzle 14' for the raw material gas.
4, and FIG. 3 is a schematic cross-sectional view of the device shown in FIG. 1. Note that the symbols given in FIG. 2.3 are the same as those in FIG. 1, and the arrows in FIG. 3 indicate the diffusion state of the raw material gas.

In the apparatus shown in FIGS. 1 to 3, the raw material gas supply pipe 14
The shape of the nozzle 1 is triangular prism, and a comb-shaped raw material gas discharge nozzle 14' is provided from one corner of the side wall.
Since the tip of 4' is directed into the plasma generation region 9,
The raw material gas discharged from the tip of the nozzle 14' diffuses in the direction of the arrow shown in FIG. This greatly improves the utilization efficiency of raw material gas. Therefore, by using this apparatus, a deposited film having a desired thickness can be formed in a short time.

Furthermore, as shown in FIGS. 1 to 3, since the raw material gas supply pipe 14 has a triangular shape, when the gas in the plasma generation region 9 is exhausted through the exhaust pipe 5, the exhaust gas has a cylindrical shape. Since the gas supply pipe 14 passes through the gap between the base 7 and the gas supply pipe 14, the exhaust conductance between each cylindrical base 7 becomes constant, and the plasma generation area 9 (11) on the surface of the cylindrical base 7 becomes constant. The concentration of the active species contributing to the reaction remains constant regardless of the location.As a result, the film deposited on the cylindrical substrate 7 has uniform thickness and properties.

The raw material gas used to form the deposited film by the apparatus of the present invention is one that is excited and speciated by high frequency or microwave energy, and undergoes chemical interaction to form the desired deposited film on the substrate surface. For example, A-3i (H,
) In the case of forming Ill, specifically, silanes and halogenated silanes in which hydrogen, halogen, or hydrocarbon, etc. are bonded to silicon, or those that can be easily gasified are used. A gasified version can be used. Ill may be used as these raw material gases, or two or more types may be used in combination, and these raw material gases may be used after being diluted with an inert gas such as Her Ar. Furthermore, A-3t(H,X
) The film can be doped with a p-type impurity element or an n-type impurity element, and a raw material gas containing these impurity elements as a constituent can be used alone or with the aforementioned raw material gas and/or for dilution. It can be mixed with a gas and introduced into the reaction chamber.

The substrate may be conductive, semiconductive, or electrically insulating, and specific examples thereof include metal, ceramics, glass, and the like. The substrate temperature during the film forming operation is not particularly limited, but is generally in the range of 30 to 450°C, preferably 5 to 350°C.

In addition, when forming a deposited film, the pressure in the reaction chamber must be set to 5X10-'Torr or less before introducing the raw material gas.
Preferably, the pressure in the reaction chamber is set to I X 10-" Torr or less, and when the raw material gas is introduced, the pressure inside the reaction chamber is I X 10"i
~l Torr, preferably 5X10-”~ITor
It is desirable to set it to r.

Note that in forming a deposited film using the apparatus of the present invention, the raw material gas is normally introduced into the reaction chamber without prior treatment (excitation speciation) as described above, where it is excited speciation by microwave energy and chemically generated. This is carried out by causing interaction, but when using two or more types of raw material gases, it is also possible to make one of them into an excited species in advance and then introduce it into the reaction chamber.

〔Example〕

Hereinafter, the formation of a functional deposited film using the apparatus of the present invention shown in FIG. 1 will be specifically explained using Examples and Comparative Examples, but the present invention is not limited thereto.

First, the inside of the vacuum container 1 is evacuated via the exhaust pipe 5, and the base cylindrical bases 7, 7. It was heated and maintained at a predetermined temperature using a built-in heater (not shown), and was constantly rotated at a desired rotational speed using a drive motor (not shown).

To these places, a raw material gas such as silane gas (stHn), hydrogen gas (Hg), diborane gas (B&H&), etc. is supplied via the raw material gas supply pipe 10 into the vacuum vessel 1 under the conditions shown in Table 1. ``0-order microwaves with a frequency of 2.45 GHz emitted while maintaining a degree of vacuum below Torr are introduced into the plasma generation region 9 through the waveguide 3 and the microwave-transparent dielectric window, and the cylindrical Base 7.7
．． A charge injection blocking layer, a photosensitive layer, and a surface layer were each formed on top of the drum to obtain a photosensitive drum having a blocking structure.

Table 2 shows the deposition rate of the photosensitive layer at this time.

Eight photosensitive drums prepared as described above were installed in a copier NP7550 manufactured by Canon Co., Ltd., and an image was outputted with the results shown in Table 2.

In addition, the "average deposition rate of photosensitive layer" in Table 2 is 8
This is the average of photosensitive drums for books, and "image quality" is the result of examining whether an image with high density, clear halftones, and high resolution is produced.

Table l Table 2 Table O... Very good ○... Good×...
A plurality of drums were produced under the same production conditions as in Example 1, except that the production conditions of the photosensitive layer were changed as shown in Table 3, and the same measurements as in Example 1 were carried out. As a result of the evaluation, good results as shown in Table 4 were obtained.

Table 3 Table 4 O... Very good 0... Good×...
Impractical comparison ■ Using the film forming apparatus shown in Figure 5 and the manufacturing conditions shown in Table 1,
A photosensitive drum was prepared in the same manner as in Example 1, and the same measurements and evaluations were performed, and the results shown in Table 5 were obtained.

Table 5 ◎... Very good O... Good X...
Impractical [Summary of Effects of the Invention] The functional deposited film forming apparatus using the MW-PCVD method of the present invention has the shape of the raw material gas supply pipe that has the function of efficiently introducing the raw material gas into the plasma generation region, and the plasma By having a shape that also has the function of adjusting the exhaust in the generation area, stable plasma can be generated, and
The gas introduction efficiency into the plasma generation region is greatly improved, and as a result, a deposited film can be formed on the substrate stably and at high speed.

Furthermore, dense deposited films that are electrically, optically, or photoconductively excellent can be efficiently mass-produced.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a typical example of a functional deposited film forming apparatus using the MW-PCVD method of the present invention, FIG. 2 is a side view of a raw material gas supply pipe in the apparatus shown in FIG. 1, and FIG. 1 is a schematic cross-sectional view of the apparatus shown in FIG. 1; FIG. 4 is a schematic perspective view of a functional deposited film forming apparatus using the conventional MW-PCVD method, FIG. 5 is a schematic perspective view of a functional deposited film forming apparatus using the MW-PCVD method suitable for mass production, and FIG. FIG. 5 is a side view of the raw material gas supply pipe in the apparatus shown in FIG. 5, and FIG. 7 is a schematic cross-sectional view of the apparatus shown in FIG. In the figure, 1... vacuum container, 2... dielectric window, 3
... waveguide section, 4 ... microwave, 5 ... exhaust pipe,
6... Raw material gas supply pipe, 6'... Raw material gas discharge hole,
7... Cylindrical base, 8... Built-in heater, 9...
...Plasma generation area, lO... Raw material gas supply pipe, 1
0'... Raw material gas discharge nozzle.

Claims (3)

[Claims] (1) A sealed vacuum container, means for holding a plurality of functional deposited film forming substrates in the vacuum container, means for supplying raw material gas into the vacuum container, and means for evacuating the inside of the vacuum container;
and a means for generating microwave discharge plasma in the vacuum container. Functional deposited films are formed on multiple substrates using the microwave plasma CVD method, which is characterized by having both the function of efficiently introducing source gas into the plasma generation region and the function of adjusting exhaust gas within the plasma generation region. A device that forms at the same time. (2) The source gas supply means is a triangular prism-shaped gas supply pipe having a plurality of nozzles protruding in a comb shape from one corner of the side wall of the triangular prism. Microwave C described in claim (1)
A device that simultaneously forms functional deposited films on multiple substrates using the VD method. (3) The raw material gas supply means has at least one
Claim (1) or (2)
An apparatus for simultaneously forming functional films on a plurality of substrates by the microwave CVD method described in 1.