JPS6244578A - Deposited film forming device by plasma cvd method - Google Patents

Abstract

PURPOSE:To improve the various characteristics and reproducibility of deposited film and the uniformity and homogeneity of the film quality and to make efficient mass production by providing a leak high-frequency wave path having a means for adsorbing a high frequency, etc., or a leak microwave path in a reaction chamber. CONSTITUTION:Flat plate-shaped substrates 32 are imposed on a substrate 32 supporting member 31 and the inside of the reaction chamber A of a reaction vessel 2 is maintained under a prescribed degree of vacuum. After the temp. of the substrates 32 is maintained at an adequate temp., gaseous raw material such as SiH4 for forming the deposited films is diluted with hydrogen and is introduced from a supply pipe 5 into the reaction chamber A. The inside pressure is regulated to a specified degree and thereafter the above-mentioned member 31, e.g., the substrates 32 are oscillated by operating an oscillator 7, then the circulation of water of the means 10 for adsorbing the high frequency or microwave is started; at the same time, the high frequency or microwave is radiated from the lead high-frequency or microwave path 4 into the chamber A. The substrates are held for the prescribed time in this state, by which the deposited films are formed on the surfaces of the substrates 32.

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, and an imaging device. , plasma CV, which is optimal for forming non-monocrystalline deposited films such as amorphous or polycrystalline for use in photovoltaic devices, etc.
Regarding D device.

[Description of prior art]

Conventionally, semiconductor devices, photosensitive devices for electrophotography,
Element members used for image input line sensors, imaging devices, photovoltaic elements, etc. include amorphous silicon, hydrogen and/or halogens (e.g. fluorine,
Amorphous silicon (hereafter ff1) compensated with chlorine, etc.)
It is written as ra-8i(H,X)J. ) membranes etc. have been proposed,
Some of them are put into practical use. Along with such a-Si(H;X) films, those a-8i(H;
, It is widely used in general.

By the way, in the plasma CVD method, a deposited film forming gas is excited and speciated (radicalized) in the vicinity of the substrate surface using high frequency or microwave energy to cause chemical interaction, and a film is deposited on the substrate surface. The device for this purpose is of the type shown in Figure 4, in which both the antenna or waveguide and the substrate are fixed to a means for radiating radio frequency or microwave waves. . [In the figure, 101 is a reaction vessel, 1o2 is a raw material gas introduction pipe, 106 is a high frequency or microwave power source, 104 is a waveguide, 105 is a transmission window, 106 is a substrate, 107 is a substrate holding stage, 10B is a heater, 109 is the gas exhaust pipe. ] However, in such conventional plasma CVD devices, as mentioned above, during operation, the waveguide and the substrate are both fixed, and the high frequency or microwave electromagnetic field is localized, and the electric field is Fig. 5-a [In the figure, a shows a distribution curve of electric field strength of high frequency or microwave in the reaction space. ], the intensity is distributed as shown in
The intensity distribution of this electric field depends on the wavelength of the applied high frequency or microwave, so in the end, the raw material gas for forming the deposited film introduced into the system is excited at a density that follows the intensity distribution of the electric field. Since the excited speciation occurs, the deposited film is as shown in FIG. ] As shown in ], it is naturally thicker in areas where the electric field is strong;
It also becomes thinner in weak areas, which has an adverse effect on the thickness, density, hardness, and even composition of the deposited film that is formed, especially when the substrate is longer than the wavelength mentioned above. However, there is a problem in that it is difficult to consistently obtain a desired deposited film product with excellent properties.

Although it is possible to manufacture a somewhat satisfactory deposited film product using the conventional plasma CVD deposited film forming apparatus described above, in this case, strict selection of various parameters is required. However, with regard to such strictly selected parameters, one of the constituent factors is plasma, and if it is left in an unstable state, the film formed will be significantly adversely affected. There is a problem in that the product becomes unviable. Therefore, the configuration of the device is naturally complex and must be designed to accommodate any number of carefully selected ξ parameters if the device scale, type of raw material gas, etc. change.

For these reasons, although the plasma CVD method is considered to be the most suitable method at present, as mentioned above, mass production of the desired deposited film requires a large amount of equipment investment. In such a situation, the process control items required for mass production are many and complex, the process control tolerance is narrow, and equipment adjustments are delicate, resulting in problems such as making the product considerably expensive. be.

On the other hand, as the various devices mentioned above have become more diversified, they have become more and more diverse. There is a social demand for a constant supply of stable deposited film products at low cost, and there is a strong desire for the development of an apparatus that satisfies this demand.

[Purpose of the invention]

The present invention solves the above-mentioned problems and meets the above-mentioned requirements regarding conventional apparatuses for forming deposited films used for photovoltaic elements, semiconductor devices, image input line sensors, Tfil devices, electrophotographic photosensitive devices, etc. The purpose is to satisfy the following.

In other words, the main object of the present invention is to have electrical, optical, and photoconductive properties that are virtually always stable regardless of the usage environment, to have excellent light fatigue resistance, and to be able to withstand repeated use. Excellent durability, with no deterioration phenomenon even under
Plasma CV that forms improved deposited films that are moisture resistant and uniform and free from residual potential problems.
An object of the present invention is to provide a deposited film forming apparatus using method D.

Another object of the present invention is to improve the characteristics, film formation speed, and reproducibility of the film to be formed, and to make the film uniform and homogeneous, while making it suitable for large-area films and improving film productivity. Another object of the present invention is to provide a deposited film forming apparatus using a plasma CVD method that can be easily mass-produced.

[Structure and effect of the invention]

As a result of extensive research in order to overcome the above-mentioned problems with the conventional apparatus and achieve the above-mentioned purpose, the present inventor has discovered that the electric field intensity distribution of the above-mentioned conventional plasma CVD deposited film forming apparatus is as follows. By making it uniform in the vicinity of the base, the above-mentioned problems were solved, and the present invention was completed based on the knowledge that the above-mentioned objects could be achieved. That is, the apparatus of the present invention has a reaction chamber that is sealed and equipped with a raw material gas supply port and an exhaust port, has a substrate mounting means equipped with a heating means in the reaction chamber, and has a heat exchanger from a source. In a deposited film forming apparatus using a plasma CVD method, which emits high frequency waves or microwaves into the reaction chamber, excites the source gas with the energy thereof, causes chemical interaction, and forms a deposited film on the substrate surface. , a leaky high-frequency path or a leaky microwave path for radiating high-frequency waves or microwaves is provided in the reaction chamber, and an end of the leaky high-frequency path or leaky microwave path is connected to a high-frequency or microwave absorbing means. It is something.

Since the apparatus of the present invention makes the intensity distribution of the electric field uniform in the vicinity of the substrate during the deposited film forming operation, the deposition rate can be dramatically increased compared to conventional deposited film forming apparatuses. In addition, even when the substrate is longer than radio frequency or microwave wavelengths, it is possible to efficiently deposit films with stable product film quality, thickness, and electrical, optical, and photoconductive properties. It allows mass production and also allows deposited film products to be provided at low cost.

The raw material gas used to form the deposited film by the apparatus of the present invention is a type 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. Any type of material can be used, but for example, a-8i (H,
X) When forming a film, specifically, silanes and rhodanized silanes in which silicon is bonded with hydrogen, hydrogen, or hydrocarbons, or easily It is possible to use gasified materials that can be gasified. These source gases may be used alone or in combination of two or more. Further, these raw material gases may be used after being diluted with an inert gas such as He or Ar. Furthermore, the a-8i (H, can be mixed with the raw material gas and/or the diluent 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 60 to 450°C, preferably 50 to 350°C.

In addition, when forming a deposited film, the pressure inside the reaction chamber is set to s x io''-6 Tor before introducing the raw material gas.
r or less, preferably 1x 10-6 Torr or less,
When introducing the raw material gas, the pressure inside the reaction chamber is set to 1×10~
1 Torr, preferably 5×10 to 1 Torr.

Note that in forming a deposited film using the apparatus of the present invention, as described above, the raw material gas is normally introduced into the reaction chamber without prior treatment (excited speciation), where it is excited and speciated using radio frequency or microwave energy. This is done by causing chemical 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. be.

Hereinafter, the apparatus for forming a deposited film using the plasma CVD method of the present invention will be explained in more detail with reference to the embodiments shown in the schematic diagrams of FIGS. 1 to 3, but the apparatus of the present invention is not limited thereto.

Note that common symbols in FIGS. 1 and 2 indicate the same components as in the explanation in FIG. 1.

FIG. 1 is a schematic diagram of the entire apparatus for forming a deposited film using the plasma CVD method of the present invention, and FIG. 2 is a perspective view of a part of the leaky high-frequency path or the leaky microwave path in the apparatus of FIG. 1. , FIG. 6 is an explanatory diagram of a specific example of the high frequency or microwave absorbing means of the apparatus of FIG. 1.

In the figure, numeral 1 indicates the entire apparatus for forming a deposited film by the plasma CVD method of the present invention, and numeral 2 indicates a reaction vessel of the apparatus. The reaction vessel 2 is formed in a sealed manner by an integral member, and has a reaction chamber A. Reference numeral 3 denotes a base support member 3 that is installed at the upper part of the reaction chamber and has a built-in heater (not shown).
1 is a base support means for supporting the base 32 downwardly. The substrate support member 31 is mechanically coupled to an external vibrator 7 via a coupling means 71, which coupling allows the substrate support means 6 to be moved laterally or longitudinally by actuation of the vibrator. It has a structure (not shown) that can be freely vibrated. Reference numeral 4 denotes a leaky high frequency path or a microwave path that is insulated and supported at both ends of the reaction chamber A. The wave path has a space surrounded by a top plate 41, a side plate 42, and a bottom plate 46, in which high-frequency waves or microwaves propagate. Upper plate 4
1 includes slot portions 44, 44.1 arranged at predetermined intervals.・
..., and the slot portion is sealed with a sealing member 45 made of a dielectric material such as glass or ceramic to prevent raw material gas from entering inside. At one end, an excitation antenna (not shown) guided from a high frequency or microwave power source 8 is arranged so that the high frequency or microwave from the power source travels within the leaky wave path. . The other end is connected to high frequency or microwave absorption means 10. 5 is a raw material gas supply pipe, one end of which opens into the reaction chamber A, and the other end communicates with a raw material gas supply source (not shown) via a valve means (not shown). Reference numeral 6 denotes an exhaust pipe υ, one end of which opens into the reaction chamber A, and the other end communicating with an exhaust system (not shown) via a valve means (not shown). The ten high frequency or microwave absorption means may be any means as long as it can efficiently absorb them, and a specific example thereof is the means shown in FIG. 3. That is,
Reference numeral 101 denotes a glass tube, which has a bluntly tapered open end and is located in the extension space of the leaky high-frequency wave path or the leaky microwave path, and the glass tube is hermetically sealed and circumferentially connected to the wall 106 at its peripheral wall surface. The glass tube 101 has a circulating water pipe line 102 in its center, and has a structure in which circulating water flows in from above and flows out in the d direction.

In the deposited film forming apparatus using the plasma CVD method of the present invention having the above configuration, during the film deposition operation, the high frequency or microwave radiated from the excitation antenna is transmitted to the slot section 44 installed in the leaky high frequency path or the leaky microwave path 4. ,
44. The high frequency waves or microwaves that travel inside the leaky high frequency path or the leaky microwave path while leaking upward from . . . and reach the end of the wave path are continuously absorbed by the absorption means 10, waves, and the intensity distribution of the electromagnetic field caused by the stationary radio frequency or microwave disappears. As a result, the intensity distribution of the electric field near the substrate in the reaction chamber A becomes uniform in terms of time integration, so the excitation speciation of the source gases and their density distribution in the reaction chamber A become uniform. As a result, the film deposited on the surface of the substrate 32 becomes uniform and homogeneous, making it possible to obtain a deposited film product of desired quality and rich in properties.

At that time, when the vibrator 7 is simultaneously operated to vibrate the base support member 3, that is, the base body 32, back and forth and left and right,
The homogeneity and uniformity of the deposited film can be further improved.

The operation of the apparatus for forming a deposited film using the plasma CVD method of the present invention will be explained below by giving an example, but the following example does not have a limiting meaning to the operation of the apparatus.

EXAMPLE A photoconductive deposited film was formed on the surface of a flat substrate by operating the deposited film forming apparatus using the plasma CVD method of the present invention shown in FIGS. 1 to 3 as follows.

That is, a flat glass plate was placed on the substrate support member 31, and the inside of the reaction chamber A of the reaction vessel 2 was made to have a degree of vacuum of about 10-5 Torr. Next, the heater 36 lowers the temperature of the glass substrate by approximately 2
It was maintained at 50°C. Next, SiH4, which is a raw material gas for forming a deposited film, was diluted with hydrogen and introduced into the reaction chamber A.

After the gas flow rate became stable, the exhaust valve was adjusted to bring the internal pressure of reaction chamber A to about 0.004 Torr. After the internal pressure became constant, the vibrator 7 for vibrating the base support member 61 was activated. Water circulation to the absorption means shown in FIG. 3 was then started. At this point, radiation of microwaves of 2.45 GH7S from the leaky high frequency path or the leaky microwave path 4 into the reaction chamber A was started.

Keep it in that state for 20 minutes and apply a-8 on the surface of the glass substrate.
A deposited film of i(H,X) was formed.

When the thickness of this deposited film of a-8i (H,

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the entire apparatus for forming a deposited film using the plasma CVD method of the present invention, and FIG. 2 is a perspective view of a leaky high-frequency path or a leaky microwave path in the reaction vessel of the apparatus shown in FIG. FIG. 6 is an explanatory diagram of one specific example of the high frequency or microwave absorbing means of the apparatus of FIG. 1. FIG. 4 is a schematic diagram of a conventional device, FIG. 5-a is an explanatory diagram of the strength distribution state of a high frequency or microwave electric field in the device, and FIG. 5-b is a schematic diagram of a conventional device. FIG. 3 is an explanatory diagram of a deposition state of a deposited film formed thereon. Regarding FIGS. 1 to 3, 1... Entire apparatus, 2... Reaction vessel, 6... Substrate support means, 31... Substrate support member, 32... Substrate, 4
...Leaky high frequency path or leaky microwave path, 41...
・Top plate, 42...Side plate, 46...Bottom plate, 44...
Slot portion, 45... Sealing member, 5... Raw material gas supply pipe, 6... Exhaust pipe, 7... Vibrator, 71... Connection means, 8... High frequency or microwave power source , 10・
...Absorption means, 101...Glass tube, 102...Pipe line, 106...Terminal end of absorption means, A...Reaction chamber, c
, d... Regarding the water flow direction cylinder 4.5-a + 5-b diagram,

Claims (1)

[Claims] A deposited film forming apparatus using a plasma CVD method, which has a high frequency or microwave generation means for exciting a raw material gas for forming a deposited film to generate excited species, and a reaction chamber for forming the deposited film on a substrate. A deposited film forming apparatus using a plasma CVD method, characterized in that the reaction chamber is provided with a leaky high frequency path or a leaky microwave path having means for absorbing the high frequency wave or microwave.