JPS6362880A - Device for forming functional deposited film by microwave plasma cvd - Google Patents

Abstract

PURPOSE:To uniformize the thickness and quality of a deposited film to be formed between substrates and on the same substrate by providing a means for rotating plural functional deposited film forming substrates arranged in a vacuum vessel and rotating on their axes. CONSTITUTION:Plural cylindrical substrates 7 are arranged on a concentric circle in the vacuum vessel 1 of the film forming device, and the rotary table 14 as a means for rotating the substrates 7 is provided. The table 14 is connected to a rotating motor 16 through a gear 15, and rotated. The inside of the vacuum vessel 1 is firstly evacuated through an evacuation pipe 5, the cylindrical substrates 7, 7,... are heated by respective built-in heaters 8 and kept at a specified temp., and each substrate 7 is rotated on its axis and rotated. A raw gas is then introduced into the vacuum vessel 1 through raw gas feed pipes 6, 6,... while keeping a specified vacuum, and a deposited film is formed on the substrates 7, 7,....

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 electromotive force elements and the like.

[Description of prior art]

Conventionally, semiconductor devices, window optical 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 (hereinafter referred to as "a-Sl"
It is written 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 to be formed by a method in which a raw material gas is decomposed by direct current, high frequency, microwave, or glow discharge to form a thin film deposited on a substrate such as glass, quartz, stainless steel, or aluminum. Various devices have also been proposed.

By the way, in recent years, Braz 7 CVD using microwave
The MW-PCVD method (hereinafter referred to as MW-PCVD method) has attracted attention, and several devices have been proposed for it.
- Efforts have been made to produce the above-mentioned deposited film on an industrial scale by the PCVD method. Such conventionally proposed devices using the MW-PC:VD method typically
The device configuration is shown in a schematic perspective view in the figure.

In Fig. 3, 1 is a vacuum container, 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. In addition, since the vacuum container 1 starts the discharge by self-help discharge without using a discharge trigger, etc., the microwave 1
) (not shown) It is common to use a cavity resonator structure that resonates at the oscillation frequency of (not shown).

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. Next, in the case of forming, for example, an amorphous silicon deposited film, a raw material gas such as silane gas or hydrogen gas is supplied to a plurality of gas discharge holes 6 opened to the raw material gas supply pipe 6 through the raw material gas supply pipe 6. ', O', . . . are discharged into the vacuum container 1. Simultaneously, microwaves 4 with a frequency of 500 MHz or more, preferably 2.45 GHz, are generated from a microwave electric H (not shown), and the microwaves pass through the waveguide 3 and pass through the dielectric window 2. Vacuum vessel 1 through
be introduced within. In this way, the raw material gas introduced into the vacuum container 1 is excited and dissociated by the microwave energy, and neutral radical particles, ion particles, electrons, etc. are generated.
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-P
In order to enable mass production of a functional deposited film forming apparatus using the CVD method, it has been found that a plurality of cylindrical substrates can be arranged in a vacuum container. Section 4.5
The figures show a typical example of an apparatus that enables such mass production, with FIG. 4 being a schematic perspective view and FIG. 5 being a schematic cross-sectional view.

In Fig. 4.5, 1 is a vacuum container, 2 is a dielectric window made of alumina ceramics or quartz, 3 is a waveguide for transmitting microwaves, 9 is a microwave power source, and 4 is from the microwave power source 9. microwave. 5 is an exhaust pipe whose one end opens into the vacuum container 1 and the other end communicates with the exhaust device 1) via an exhaust valve 10; 6 is a source gas supply source (not shown) via a valve 12; 7 is a cylindrical substrate arranged concentrically, 8 is a substrate heating heater, and 13 is a plasma generation region generated in the vacuum vessel by microwaves passing through the dielectric window 3. be.

The plasma region 13 includes the dielectric window 2 and the substrate 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.

However, when forming a deposited film using this device, there are cases in which (a) the thickness of the deposited film is significantly non-uniform between substrates, or (b) the quality of the deposited film is significantly non-uniform between substrates. There was a problem that could occur.

In particular, these problems (a) to (b) are significant when a thick deposited film is formed on a long substrate such as an electrophotographic photoreceptor device.

Furthermore, differences are also recognized depending on the electric field distribution of the microwave used, and when microwaves having TE and mode electric lines of force are introduced, the occurrence of such problems is exacerbated. In addition, when microwaves are introduced into the TE mode electric lines of force, the occurrence of such problems is reduced, but the TE mode has a large loss during transmission and is not suitable for practical use.

[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 achieves the following advantages: power element,
MW-PCVD produces functional deposited films as element members used in various other electronic devices, optical devices, etc.
The object of the present invention is to provide an apparatus that enables constant and highly efficient formation by a method.

That is, an object of the present invention is to make it possible to uniformize the thickness and quality of the deposited film formed between and on the substrates in a functional deposited film forming apparatus using the MW-PCVD method, and to obtain a high quality deposited film. Our goal is to provide equipment that can regularly mass-produce products.

[Structure of the invention]

The present invention solves the above-mentioned problems in deposited film forming apparatuses using the conventional MW-PCVD method, and as a result of intensive research by the present inventors to achieve the objects of the present invention, found that various problems in the deposited film forming apparatus can be solved by rotating and revolving the substrate within the apparatus.

The present invention was completed based on this knowledge,
The apparatus for forming a functional deposited film using the MW-PCVD method of the present invention includes a sealed vacuum container, a means for holding a substrate for forming a functional deposited film in the vacuum container, and a means for supplying raw material gas into the vacuum container. , a functional deposited film forming apparatus by a microwave plasma CVD method, comprising means for evacuating the inside of the vacuum container, and means for generating microwave discharge plasma in the vacuum container, further comprising a method for forming the functional deposited film. The invention is characterized by having means for causing the base body to rotate and revolve around its axis.

Formation of a deposited film using the apparatus having the above-mentioned configuration provides a remarkable effect, particularly when using an apparatus in which the distribution of microwave electric lines of force is in the TE mode. In other words, when microwaves are used as an excitation energy source for source gas, the difference from conventional high frequency (e.g. 13.56 MHz) plasma methods is that a uniform electric field cannot be obtained in the microwave electric field distribution, and the electric field is non-uniform on the propagation surface. This results in a distribution of electric lines of force. This means that a non-uniform plasma distribution is generated in the discharge space into which microwaves are introduced, and as a result, when deposited films are formed on multiple substrates, the thickness of the deposited film is increased between and on the same substrate. In the apparatus of the present invention, such non-uniformity in film quality and film thickness can be solved by causing the substrate to rotate and revolve around the plasma generation area. The problem is resolved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus for forming a functional deposited film by the MW-PCVD method of the present invention will be described below using the apparatus of the embodiment shown in the drawings, but the present invention is not limited thereto.

FIG. 1 is a schematic cross-sectional view schematically showing a typical example of an apparatus for forming a functional deposited film by the MW-PCVD method of the present invention, and FIG. 2 is a schematic longitudinal cross-sectional view of the apparatus. In addition, in the figure, the same reference numerals as in the above-mentioned figures 4 to 6 refer to the figure 4.
This shows the same thing as explained in FIGS. That is, in FIGS. 1-2, 1 is a vacuum container, 2 is a dielectric window made of alumina ceramics or quartz, and 5 is a window with one end opening into the vacuum container 1 and the other end opening for exhaust through an exhaust valve 10. an exhaust pipe communicating with the apparatus 1), 6 a raw material gas supply pipe communicating with a raw material gas supply source (not shown) via a valve 12, 7 a cylindrical base body arranged concentrically, 8 1 is a substrate heating heater, and 13 is a plasma generation region generated in the vacuum container by microwaves passing through the dielectric window 3.

Reference numeral 14 denotes a revolution table which is a means for revolving the base body in the present invention as described above, and is connected to a rotation motor 16 via a gear 15 and driven to rotate. The driving power of the revolution table 14 for revolutionizing the substrate is not only the direct drive method from the outside as shown in the figure, but also non-contact drive,
For example, even with a magnetic drive system, the object of the present invention can be fully achieved. Further, although a drive system for rotating the substrate is not shown, it may be built in the vacuum container or may be provided outside.

Furthermore, in the illustrated apparatus, a heater 8 for heating the substrate is provided.
Although an example has been shown in which the power supply is built into the base, it may also be introduced from the outside by a slide contact method or the like.

In addition, in the apparatus shown in FIGS. 1 and 2, the vacuum vessel 1
has a cavity resonator structure that resonates with the oscillation frequency of the microwave power source 9 in order to automatically start discharging without using a discharge trigger or the like.

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 −5i (
In the case of forming a film (H, Gasified Uruchino can be used. 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 s Ar. Furthermore, a −5t(H,X
') The film can be doped with a p-type impurity element or an n-type impurity element, and the raw material gas containing these impurity elements as a constituent can be used alone or as the aforementioned raw material gas and/or diluent. 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 50 to 350°C.

In addition, when forming a deposited film, the pressure in the reaction chamber is set to 5X10-' Torr or less, preferably I IX 104~
I Tart s preferably 5×10−! ~I Tor
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. 1.2 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 cylindrical base 7, 7°...
Each of the six cylindrical substrates is heated and maintained at a predetermined temperature by a heater 8 built in the cylindrical substrates 7, 7. ...
... was rotated and/or revolved under the conditions shown in Table 2.

To these places, raw material gas supply pipe 6,6°...
..., raw material gases such as silane gas (SiH4), hydrogen gas (H□), diborane gas (Bz)Lb), etc. are placed in the vacuum vessel 1 under the conditions shown in Table 1 at a concentration of 1×lO'''!
The gas was discharged while maintaining the degree of vacuum below torr. next,
Microwaves with a frequency of 2.45 GHz are transmitted to the plasma generation region 13 through the waveguide 3 and the microwave-transparent dielectric window 2.
into the cylindrical substrate 7.7. ......A charge injection stop layer, a photosensitive layer, and a surface layer were successively formed thereon.

The photosensitive drum thus prepared was measured using an eddy current film thickness meter (Ket).
The film thickness was measured using a film thickness meter (manufactured by T Co., Ltd.), and the surface potential (TRE
Measurement using a surface electrometer (CK Co., Ltd.) gave the results shown in Table 2. Each photosensitive drum A to F in Table 2 is 1
These are tentative names for each batch created at the same time.

As is clear from the results in Table 2, in the comparative example that does not use revolution of the substrate (drum), there is significant non-uniformity in film thickness, surface potential characteristics, and sensitivity, whereas in the present invention It is clear that the substrate revolution of the present invention has excellent uniformity in both film thickness, surface potential, and sensitivity characteristics, regardless of the revolution speed, and the uniformity when the substrate revolution of the present invention is introduced is a surprising effect. Table 1 [Summary of Effects of the Invention] According to the present invention, in a deposited film forming apparatus using the MW-PCVD method, a deposited film forming base placed in a reaction vessel is rotated around its axis, thereby forming a deposited film on the base. It is possible to greatly stabilize the thickness and quality of the deposited film. Therefore t
A deposited film forming apparatus with high productivity can be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a typical example of an apparatus for forming a functional deposited film by the MW-PCVD method of the present invention, and FIG. 2 is a schematic longitudinal cross-sectional view of the apparatus shown in FIG. 1. Third
The figure is a schematic cross-sectional view of a functional deposited film forming apparatus using the conventional MW-PCVD method, and FIG. 4 is a schematic perspective view of a functional deposited film forming apparatus using the MW-PCVD method that enables mass production. FIG. 5 is a schematic longitudinal cross-sectional view of the apparatus shown in FIG. 4. In the figure: 1... Vacuum container, 2...
Dielectric window, 3... Waveguide section, 4...
...Microwave, 5...Exhaust pipe, 6
...... Raw material gas supply pipe, 7...
...Cylindrical base, 8...Heating heater,
9...Microwave power supply, 10...
...exhaust valve, 1) ...exhaust device, 12 ....... pulp, 13 ......
...Plasma generation area, 14...Revolution table, 15...Gear, 16...
...Rotation motor. Figure 4

Claims (2)

[Claims] (1) A sealed vacuum container, a means for holding a substrate for forming a functional deposited film in the vacuum container, a means for supplying raw material gas into the vacuum container, a means for evacuating the inside of the vacuum container, and the vacuum A functional deposited film forming apparatus by a microwave plasma CVD method comprising means for generating microwave discharge plasma in a container, further comprising means for rotating and revolving the base for forming the functional deposited film. A functional deposited film forming apparatus using the microwave plasma CVD method. (2) Functional deposited film formation by the plasma CVD method according to claim (1), wherein a plurality of the functional deposited film forming substrates are arranged concentrically around the plasma generation space. Device.