JPS6240380A - Deposited film forming device by plasma cvd method - Google Patents

Abstract

PURPOSE:To form a uniformly deposited film having uniform quality over the entire surface of a substrate by providing high-frequency or microwave disturbing means having a function to change the relative position of the electromagnetic field of a high frequency or microwave and substrate in a reaction vessel. CONSTITUTION:A valve 21 is closed and a valve 91 is opened to evacuate the inside of the reaction chamber A to a prescribed pressure. Electricity is then conducted to a heater 8 to hold the temp. of e substrate 6 at about 200 deg.C. The valve 21 is opened to introduced the gaseous mixture composed of gaseous SiH4 and gaseous H2 at, for example, 1:1 flow rate ratio into the reaction chamber A and is maintained under a prescribed pressure. At the same time, electricity is conducted to a microwave power source 3 to radiate the microwave through a transmission window 5. Driving devices 12, 14 are driven to run funs 11, 13. The film forming operation is made for the prescribed time while the substrate 6 is horizontally oscillated.

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]

Conventional semiconductor devices, photosensitive devices for electrophotography □
Devices, line sensors for image input, imaging devices, photovoltaic devices, etc. are used as element materials such as amorphous silicon, for example, amorphous silicon compensated with hydrogen or/and halogen (e.g. fluorine, chlorine, etc.) -3i (H,
Several methods for forming 8i (H,
There are the D method, the photo-CVD method, etc., and among them, the plasma CVD method has been put into practical use as the most suitable method and is generally widely used.

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. For this purpose, an apparatus for this purpose is of the type shown in FIG. 4, in which both the means for radiating radio-frequency or microwave waves, such as an antenna or waveguide, and the substrate are fixed. [In the figure, 101 is a reaction vessel, 102 is a raw material gas introduction tube, 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 stator, 108 is a heating means, 109 is a gas exhaust pipe. ] However, as mentioned above, in devices using conventional plasma CVD methods, both the waveguide and the substrate are fixed during operation, and the electromagnetic field of high frequency or microwave is not localized. , the electric field is, for example, the fifth
Figure -a [In the figure, a shows the distribution curve of the electric field strength of high frequency or microwave in the reaction space. ], and the intensity distribution of this electric field is as shown in
Applicable radio frequency or microwave wavelength.

As a result, the raw material gas for forming the deposited film introduced into the system is excited and becomes excited species at a density that follows the electric field intensity distribution, so the deposited film is Figure 5-b [In the figure, b shows the state of deposition of the deposited film 106 deposited on the substrate 7 in the reaction space. ], the electric field is naturally thicker in areas where the electric field is stronger and thinner in areas where the electric field is weaker, and this is especially true when the substrate is longer than the above wavelength. There is a problem in that the hardness and also the composition are adversely affected, making it difficult to consistently obtain a deposited film product with desired properties.

Although it is possible to manufacture a deposited film product that is somewhat satisfactory using a deposited film forming apparatus using the conventional plasma CVD method, which has become more advanced, in that case, strict selection of various parameters is required. . However, for such strictly selected parameters, one of them
There is a problem in that if two constituent factors, especially plasma, become unstable, the formed film will be severely adversely affected and become unusable as a product. Therefore, the configuration of the device naturally becomes complicated, and if the scale and type of the device changes, it must be designed to accommodate each carefully selected i4 meter.

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. However, the process control items for mass production are numerous and complex, the tolerance range for process control is narrow, and equipment adjustments are delicate, resulting in problems such as making the product considerably more expensive. There is.

On the other hand, the various devices mentioned above are becoming more diversified, and the element materials for them, that is, the elements that satisfy all the requirements such as the various characteristics mentioned above, are suitable for the target object and use, and in some cases are becoming larger in area. 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 with respect to conventional apparatuses for forming deposited films used in photovoltaic elements, semiconductor devices, image input line sensors, imaging devices, electrophotographic photosensitive devices, etc. The purpose is to meet the requirements of

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 durable even after repeated use. Excellent durability without causing deterioration even if
Plasma CV for forming improved deposited films that are moisture resistant and uniform and homogeneous without residual potential problems
The present invention provides 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]

The inventor of the present invention has conducted intensive research to overcome the above-mentioned problems with the conventional apparatus and achieve the above-mentioned objective. As a result, the present inventor has found that the electric field intensity distribution of the above-mentioned conventional CVD deposited film forming apparatus has been improved. By making it uniform in the vicinity of the base through a specific means, the aforementioned problems with the conventional device were solved, and the inventors obtained the knowledge that could achieve the above object, leading to the completion of the present invention. .

That is, the apparatus of the present invention comprises 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 a deposited film on a substrate. In the deposited film forming apparatus using the plasma CVD method, a high frequency or microwave disturbance means having a function of changing the relative positional relationship between the high frequency or microwave electromagnetic field and the substrate is provided in the reaction chamber. This is a characteristic feature.

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 if the substrate is longer than the radio frequency or microwave wavelength, it is possible to efficiently mass produce deposited films with stable product film quality, thickness, and electrical, optical, and photoconductive properties. It also makes it possible to provide deposited film products at low cost.

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-8i (H,
) If a film is to be formed, 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. 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-81 (E, Alternatively, it can be mixed with the aforementioned raw material gas and/or diluting gas and introduced into the reaction space.

The substrate may be conductive, semiconductive, or electrically insulating, and specific examples 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 in the reaction space is reduced to 5 x 10' Torr before introducing the raw material gas.
Hereinafter, the pressure in the reaction space is preferably 1×10 Torr or less, and when the raw material gas is introduced, the pressure in the reaction space is 1×10 Torr or less.
1'Torr preferably 5X10-1~IT
It is desirable to set it to orr.

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 space without prior treatment (excited speciation), where it is excited and speciated using high frequency or microwave energy. This is carried out 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 space.

Hereinafter, the deposited film forming apparatus using the plasma CVD method of the present invention will be explained in more detail with reference to the embodiments shown in FIGS. 1 and 2.
The deposited film forming apparatus of the present invention is not limited to these.

FIG. 1 shows high-frequency or microwave waves radiated into a reaction chamber through a transmission window as a high-frequency or microwave disturbance means having the function of changing the relative positional relationship between a high-frequency or microwave electromagnetic field and the substrate. One fan is provided at the front in the direction of movement of the reaction chamber and immediately in front of the side wall of the reaction chamber opposite to the side wall of the reaction chamber provided with the transmission window, and the raw material gas is introduced into the reaction chamber from the raw material gas introduction pipe. 2 is a schematic cross-sectional view schematically showing a deposited film forming apparatus using a plasma CVD method of the present invention, in which another fan is provided at a position immediately after the first fan.

In FIG. 1, reference numeral 1 denotes a vacuum vessel having a reaction chamber A sealed by earthen walls, side walls, and a bottom wall. The vacuum vessel 1 has a raw material gas supply pipe 2 at its upper side wall, one end of which opens into the reaction chamber A, the other end of which communicates with a raw material gas supply source (not shown) and is equipped with a valve means 21. Further, at the lower part of the side wall opposite to the side wall, there is provided an exhaust pipe 9, one end of which opens into the reaction chamber A, and the other end of which communicates with an exhaust device (not shown) via a valve means 91.

3 is a high frequency or microwave power source, and the high frequency or microwave generated by the power source is passed through a three-pole matching box (
(not shown), a rectangular waveguide (not shown), and a waveguide 4 connected to the power source via an isolator (not shown). The light is emitted into the reaction chamber A through a transmission window 5 fitted into the side wall. The transmission window 5 is composed of a plate that transmits high frequency waves or microwaves, and is preferably made of highly heat-resistant silicone resin, Teflon, or alumina (At2
03) Made of dielectric material such as ceramics.

Reference numeral 7 denotes a holding stage for the base body 6, which includes a built-in heating means 8 for heating the base body 6.

Reference numeral 11 denotes a fan having blades made of a material that reflects high frequency waves or microwaves, such as a conductor such as aluminum or iron. It is attached to the side wall of the vacuum container on the side having the exhaust pipe 9, and is connected to a variable rotation speed driving device 12 provided outside the vacuum container. FIG. 6 is an illustration of the shape of the fan,
Reference numeral 111 indicates a fan made of a material that reflects high frequencies or microwaves, but the shape of the fan used is not limited thereto. The high frequency waves or microwaves radiated into the reaction chamber A are reflected by the fan 11 rotated by the drive device 12, so the relative positional relationship between the electromagnetic field generated by the high frequency or microwave radiation and the base 6 is determined by the fan 11. It changes according to the rotation of. the result,
Since the intensity distribution of the electromagnetic field near the surface of the substrate 206 is uniform when time-integrated, the density distribution of excited species generated by the electromagnetic field is also uniform, resulting in uniform film quality over the entire surface of the substrate. And it becomes possible to form a deposited film having a uniform thickness.

Reference numeral 13 denotes a fan provided at a position immediately after the raw material gas is introduced into the reaction chamber A from the aforementioned raw material gas introduction pipe 2, and the rotation of the fan reflects the gas flow of the raw material gas. It is set up so that The shape of the fan 13 is similar to the fan 11 described above, and the fan 13 is also connected to a variable rotation speed drive device 14 provided outside the vacuum container; however, in the case of the fan 11 described above, It does not have to be made of a material that reflects high frequencies or microwaves, as in the case of

Since the gas flow of the raw material gas is introduced into the reaction chamber A, it is reflected and disturbed by the fan 16 rotated by the drive device 14, so that the relative position of the base 6 and the gas flow of the raw material gas is changed by the fan 16. As the gas flow changes, the intensity distribution of the electromagnetic field generated by radio frequency or microwaves and the distribution of the excited species generated by the electromagnetic field also change due to the change in the gas flow. As a result, the effect that the distribution of excited species in the vicinity of the surface of the substrate 6 becomes uniform when viewed as a time integral on the surface of the substrate 6 can be achieved more efficiently.

Reference numeral 10 denotes a drive device provided outside the vacuum container, which is connected to the substrate holding stage 7 via any mechanical means, and is configured to horizontally swing, vertically move, or rotate the substrate stage. It is. Horizontal rocking, vertical movement, rotation, etc. of the substrate stay shift are performed as necessary, but horizontal movement, vertical movement, or rotation, or two or more of these, of the substrate holding stage 7 during the deposited film forming operation. When performing a combination of It becomes homogeneous, and various kinds.

The effect of the apparatus of the present invention, which is the ability to stably obtain a desired deposited film with rich properties, can be achieved even more efficiently.

FIG. 2 is a schematic cross-sectional view schematically showing another embodiment of the deposited film forming apparatus using the plasma CVD method of the present invention. This is a modification, and the two fans provided in the embodiment of FIG. 1 are replaced with one fan. In FIG. 2, the same symbols as in FIG. 1 are used to indicate the components of the device having the same functions as those in the embodiment of FIG. That is, 1 is a vacuum container, 2' is a gas introduction tube, 21' is a pulp means, 3 is a high frequency or microwave power source, 4 is a waveguide, 5 is a transmission window, 6 is a substrate, 7 is a substrate holding stage, 8
' is a heating means, 9 is an exhaust pipe, 91 is a pulp means, 10
1 is a drive device for the holding stage 7, 11 is a fan, and 12 is a drive device whose rotation speed is variable.

In the embodiment shown in FIG. 2, a transmission window 5 is fitted into one side wall of the vacuum vessel, and at the bottom of the side wall, one end opens into the reaction chamber A and the other end opens through a valve means 91'. It has an exhaust pipe 9' communicating with an exhaust system (not shown). The other side wall opposite to this side wall has a gas introduction pipe 2' at a position corresponding to the center position of the fitted transmission window 5, and one end of the gas introduction pipe is connected to the inside of the reaction chamber A. The other end communicates with a gas supply source (not shown) via valve means 21'. Then, the gas introduction pipe 2' in the vacuum container
Immediately before the opening of the fan 11, a fan 11 having blades made of a material that reflects high frequency waves or microwaves is provided so as to reflect the high frequency waves or microwaves that are emitted and proceed through the above-mentioned transmission window. The fan is connected to a variable rotation speed drive device 12 similar to the embodiment shown in FIG. In the apparatus of this embodiment, the high frequency or microwave is reflected by the fan rotated by the drive device 12, and the raw material gas introduced into the reaction chamber A does not flow in a steady flow. spread to. As a result, the intensity distribution of the electromagnetic field generated by high frequency or microwave becomes uniform when integrated over time, and the density distribution of excited species on the substrate surface also becomes uniform when integrated over time. The film deposited on the surface becomes uniform and homogeneous, making it possible to stably obtain a desired deposited film with rich properties. In the case of the embodiment shown in FIG. 2, the substrate holding stage 7 may be horizontally oscillated, vertically moved, rotated, or a combination of two or more of these may be performed by the driving device 10 as necessary. It can be carried out intermittently or continuously, and in such a case, the effect that the deposited film formed is uniform and homogeneous can be achieved more efficiently.

In addition, in the above-mentioned FIGS. 1 and 2, as a high frequency or microwave disturbance means that changes the relative positional relationship between the electromagnetic field of high frequency or microwave and the substrate, a material made of a material that reflects high frequency or microwave is used. Although the case is shown in which a fan with blades is used, the disturbance means is not limited to this, and has the function of changing the relative positional relationship between the high frequency or microwave electromagnetic field and the base body. Needless to say, it's fine if it's something.

Next, an example of forming a deposited film by operating the apparatus of the present invention will be described.

Example 1 In this example, the apparatus shown in FIG.
was activated to cause horizontal oscillation. In addition, as a raw material gas,
A mixed gas of SiH4 gas and H2 gas was used.

First, close the valve 21, open the valve 91, and open the reaction chamber A.
The inside was evacuated and the system pressure was reduced to below I x 10-6 Torr. Next, the heater 8 is energized to raise the temperature of the base 6 to 2.
The temperature was maintained at 00°C. There, the valve 21 is opened and the above mixed gas (gas flow rate ratio 1 2 1) is passed through the raw material gas introduction pipe 2.
'& Introduce until the system pressure reaches 1 x 10-2 Torr, and at the same time, energize the microwave power supply B to radiate microwaves with a frequency of 2.45 GHz through the transmission window 5, and The fan 11 is driven by the drive device 12.14.
It was rotated by 15 degrees. At this point, the system pressure was kept constant by adjusting the introduction and exhaust of the raw material gas with the valves 21 and 91, and the film formation operation was performed at predetermined times while horizontally swinging the substrate 6.

Thereafter, the operation was stopped, the substrate was allowed to cool, and then the substrate was transported out. The same operation was repeated on nine other new substrates to obtain a total of 10 substrates on which the film was deposited. When we tested the deposited films on the surfaces of these 10 substrates, we found that all of them had extremely dense compositions, were uniform and homogeneous, and had excellent electrical, optical, and photoconductive properties. It was extremely good.

Example 2 The vibrator 10 was not operated, that is, the substrate 6 was kept stationary without being shaken, and the other operations were the same as in Example 1, so that a film was deposited on a total of 10 surfaces. A substrate was obtained. When the films deposited on the surfaces of these 100 substrates were tested, in the case of Example 1 (the substrate had extremely excellent gaseous, optical, and photoconductive properties).

[Summary of effects of the invention]

The deposited film forming apparatus using the plasma CVD method of the present invention provides a high-frequency or microwave agitation means that has a function of changing the relative positional relationship between the high-frequency or microwave electromagnetic field and the substrate in the reaction chamber. The intensity distribution of the electromagnetic field in the vicinity becomes uniform when integrated over time, and as a result, the density distribution of excited species generated on the substrate surface also becomes uniform, resulting in uniform and homogeneous deposition over the entire surface of the substrate. A film can be formed, and a deposited film having desired excellent properties can be stably obtained.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams showing an embodiment of the deposited film forming apparatus using the plasma CVD method of the present invention, and FIG.
．． The shape of the fan of the device shown in FIG. 2 explains the intensity distribution of the high frequency or microwave electromagnetic field in the device. Regarding Figures 1 to 3, 1... Vacuum vessel, 2.2'... Raw material gas supply pipe, 2
1゜21'...Valve, 6...High frequency or microwave power supply, 4...Wave pipe, 5...Transmission window, 6...
Substrate, 7... Substrate holding stage, 8... Heating means,
9,9'...Exhaust pipe, 91.91'...Valve, 1
0... Drive device, 11.13... Fan, 111.
...Blade, 12.14...Drive device with variable rotation speed, A
... Regarding the reaction chamber Figs. 4 and 5, 101 ... Vacuum container, 102 ... Raw material gas introduction pipe,
103...High frequency or macro f wave power supply, 104...
... waveguide, 105 ... transmission window, 106 ... base body,
107...Substrate holding stage, 108...Heating means, 109...Gas exhaust pipe, a...Intensity distribution state of electromagnetic field

Claims (1)

[Claims] Plasma CVD comprising 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 a deposited film on a substrate.
The apparatus for forming a deposited film by the method is characterized in that a high frequency or microwave disturbance means having a function of changing the relative positional relationship between the high frequency or microwave electromagnetic field and the substrate is provided in the reaction chamber. A deposited film forming apparatus using the plasma CVD method.