JP2867150B2 - Microwave plasma CVD equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a deposited film on a substrate, especially a functional film, especially a semiconductor device, a photoconductor for electrophotography, a line sensor for image input, an imaging device, and a photovoltaic device. Microwave plasma CVD for forming amorphous semiconductor films used for devices, etc.
Related to the device.

[Description of Prior Art]

Conventionally, semiconductor devices, photoreceptors for electrophotography, line sensors for image input, imaging devices, photovoltaic devices,
As other element members used for various electronic elements, optical elements, etc., amorphous silicon, for example, amorphous silicon compensated with hydrogen and / or halogen (eg, fluorine, chlorine, etc.) (hereinafter referred to as “A-Si (H, X)”) ) Have been proposed, and some of them have been put to practical use.

And such a deposited film is a plasma CVD method, that is,
It is formed by a method of decomposing a raw material gas by discharge energy such as direct current, high frequency, or microwave, and forming a thin film deposition film on a base material such as glass, quartz, a heat-resistant synthetic resin film, stainless steel, or aluminum. It has been known that various devices have been proposed.

Meanwhile, in recent years, a plasma CVD method using a microwave glow discharge decomposition method has attracted attention, and research for industrial use has been made.

By such typical microwave glow discharge decomposition method
A CVD apparatus is disclosed in JP-A-59-078528.
Furthermore, JP-A-61-283116 discloses microwaves.
There is a disclosure of an improved apparatus by the CVD method, in which the electrode is installed in the discharge space and a desired voltage is applied to control the plasma potential in the discharge space, thereby controlling the ion bombardment of the deposited species. A method for performing film deposition is described, and it is disclosed that according to the method, the characteristics of a film formed are substantially improved.

Such a conventional apparatus for forming a deposited film by a microwave plasma CVD method is typically shown in FIGS. 4 and 5.

FIG. 4 shows a type in which one substrate is installed, and FIG. 5 shows a type in which a plurality of substrates can be installed simultaneously.

In FIG. 4, reference numeral 401 denotes a reaction vessel, which has a vacuum tight structure. Reference numeral 402 denotes a dielectric window formed of a material capable of efficiently transmitting microwave power into the reaction vessel and maintaining vacuum tightness, for example, quartz glass, alumina ceramics, or the like. Reference numeral 403 denotes a microwave transmission unit mainly composed of a metallic waveguide, which is connected to a microwave power supply (not shown) via a matching device isolator. An exhaust pipe 404 has one end opening into the vacuum vessel 401 and the other end communicating with an exhaust device (not shown). 40
Reference numeral 5 denotes a substrate for forming a deposited film, and reference numeral 406 denotes a discharge space.
Reference numerals 409 and 410 denote a power supply and electrodes for controlling the plasma potential, respectively.

The description of the device shown in FIG. 5 is substantially the same as that of FIG.
Along the direction.

The formation of a deposited film by such a conventional deposited film forming apparatus is generally performed as follows when the apparatus shown in FIG. 4 is used, for example.

That is, the reaction vessel 401 is operated by a vacuum pump (not shown).
The inside is evacuated, and the pressure inside the reaction vessel 401 is adjusted to 1 × 10 ⁻⁷ Torr or less. Next, a heater built in the substrate holder 407 is energized to heat and maintain the temperature of the substrate 405 at a temperature suitable for forming a desired film deposition. In the case of forming an amorphous silicon deposition film, for example, a source gas such as silane gas (SiH ₄ ) is introduced into the reaction vessel 401 via the source gas introduction pipe 408. At the same time, power is supplied to a microwave power supply (not shown) to generate a microwave having a frequency of 500 MHz or more, preferably 2.45 GHz, and the inside of the reaction vessel 401 through the waveguide 403 and the dielectric window 402. Will be introduced.

Thus, the gas in the reaction vessel 401 is excited and dissociated by the energy of the microwave, and a deposited film is formed on the substrate surface.

By using such a conventional deposited film forming apparatus, a relatively thick photoconductive material can be formed at a high deposition rate.

However, such a conventional apparatus is still inadequate in terms of characteristics and economy when producing a member requiring uniform characteristics over a large area such as an electrophotographic photosensitive member.

That is, when the source gas is introduced from outside the plasma space, the source gas decomposes and ionizes one after another when it enters the plasma. At this time, the upstream side (source gas inlet side) and the downstream side (source gas exhaust means side) of the source gas in the plasma.
Radical concentration and ion concentration at the time vary greatly.

For this reason, the amount and intensity of ion collision on the substrate change between the upstream side and the downstream side, resulting in non-uniformity of the deposited film thickness and electrical characteristics.

In addition, since the raw material gas enters the plasma from the outside of the plasma, there is a case where the raw material gas is exhausted without being decomposed without passing through the plasma center having a strong plasma intensity.
The raw material gas utilization efficiency is now one step away.

Further, since the source gas is supplied from outside the plasma, the ionization is mostly performed at a position far from a bias electrode provided inside the plasma. Therefore, the energy of the ions is not sufficiently high with respect to the substrate, and the bombardment of the substrate becomes insufficient. At this time, if the voltage of the bias electrode is increased for the purpose of sufficiently enhancing the effect of the bombardment, abnormal discharge from the bias electrode such as spark occurs.

On the other hand, when the source gas introducing means is provided inside the plasma, the source gas always passes through the center of the plasma, so that the decomposition is sufficiently performed, but the source gas introducing means provided in the plasma and the flow of the source gas are provided. As a result, an electric field in the plasma is generated, and the uniformity of the thickness and the electrical characteristics of the deposited film on the substrate is not sufficient.

In particular, when a plurality of substrates are provided so as to surround the plasma in order to increase the source gas use efficiency, the effect becomes remarkable.

This effect is a problem not only in the case where the source gas introducing means is a conductor, but also in the case where the source gas introducing means is an insulator. As the deposited film is formed on the surface of the source gas introducing means, the electric field in the plasma further increases. .

[Object of the invention]

The present invention overcomes the problems of the conventional apparatus as described above, and provides a semiconductor device, an electrophotographic photoreceptor device, an image input line sensor, an imaging device, a photovoltaic element, various other electronic elements, and an optical element. To provide a device capable of forming a uniform film at a high speed and stably while further improving the utilization efficiency of the source gas by using a device capable of forming the element members used for the microwave plasma CVD method or the like. It is the purpose.

[Structure and effect of the invention]

The inventor of the present invention has conducted intensive research to overcome the above-mentioned problems in the conventional deposition apparatus for forming a film by the microwave CVD method. As a result, in order to obtain a stable and high-quality deposition film with a microwave plasma CVD apparatus at a high speed. Can be solved by applying a voltage to the source gas introducing means such that the source gas introducing means is located inside the discharge space, and an electric field is applied between the source gas introducing means and the substrate. Obtained knowledge.

The present invention has been completed based on the above findings. The microwave plasma CVD apparatus according to the present invention includes a reaction vessel capable of being vacuum-tight and having a discharge space, a mechanism for disposing a substrate on which a deposited film is formed in the reaction vessel, and a raw material in the discharge space. A source gas introducing means for introducing a gas, and a microwave introducing means for introducing a microwave into the discharge space; a source gas and microwave energy are introduced into the discharge space; A microwave CVD apparatus for forming a deposited film on the substrate by an excited glow discharge, wherein the source gas introducing unit has a cylindrical shape formed of a conductive material, At least a portion of the substrate is located in the discharge space and along a substrate disposed in the reaction vessel, and an electric field is applied between the substrate and the source gas introducing means. In, wherein the power supply to the conductive material portions of the material gas introduction means is connected.

Hereinafter, examples specifically showing the configuration of the microwave plasma CVD apparatus of the present invention are shown in FIGS.

FIG. 1 shows that a film is deposited on a flat substrate, and FIG. 2 shows that a film is deposited on a plurality of flat substrates.
FIG. 3 shows a case in which film deposition is performed on a plurality of cylindrical substrates, and a source gas introducing means is provided at the center of a discharge space surrounded by the plurality of cylindrical substrates. An electric field is applied between the means and the cylindrical substrate. Here, FIG. 3 (A) and FIG. 3 (B) show a longitudinal sectional view and a transverse sectional view, respectively.

In FIG. 1, 101 is a reaction vessel, 102 is a microwave introduction window, 103 is a waveguide, 104 is an exhaust pipe, 105 is a flat substrate, 106 is a discharge space, 107 is a substrate holder, 108 is source gas introducing means, 109 Indicates a power source. 2 in Fig. 2
01 is a reaction vessel, 202 is a microwave introduction window, 203 is a waveguide,
204 is an exhaust pipe, 205 is a plurality of flat substrates, 206 is a discharge space, 2
07 is a substrate holder, 208 is a raw material gas introducing means, and 209 is a power source. In FIG. 3, 301 is a reaction vessel, 302 is a microwave introduction window, 303 is a waveguide, 405 is an exhaust pipe, 305 is a cylindrical substrate, 306 is a discharge space, 307 is a heater, 308 is a source gas introduction means, Reference numeral 309 denotes a power supply, and reference numeral 311 denotes a rotation mechanism.

Such a method of forming a deposited film by the apparatus according to the present invention is performed, for example, in FIGS. 3A and 3B as follows.

First, the inside of the vacuum reactor 301 is evacuated by a vacuum pump (not shown) through an exhaust pipe 304. Next, the cylindrical substrate
The heater 305 is energized to a heater 307 to raise the temperature to a predetermined temperature and hold it. Then, the cylindrical body 305 is rotated by the rotation mechanism 311.
Is rotated, and silane gas (Si
A source gas such as H ₄ ) or diborane (B ₂ H ₆ ) is supplied into the reaction vessel 301. Next, a predetermined DC voltage is applied to the source gas introduction pipe 308 from the power supply 309, and then a 2.45 GHz microwave generated by a microwave generator (not shown) is matched with a matching device (not shown) and a waveguide. It is introduced into the discharge space 306 through the microwave introduction dielectric window 302 through 103.

Thus, the source gas introduced into the discharge space 306 is
Excited by microwave energy and dissociated, neutral radical particles, ionic particles, electrons, etc. are generated, which react with each other to form a deposited film over the entire surface of the rotating cylindrical substrate 305. It is where it is done.

The material of the raw material gas introduction means used in the present invention may be any conductive material, for example, stainless steel, Al, Cr, Mo, Au, In, Nb, Ni, Te, V, Ti, Pt, Pd In the present invention, metals such as Fe, Fe and the like, alloys thereof, and glass and ceramics whose surfaces are subjected to a conductive treatment are usually used.

Further, the shape of the raw material gas introducing means is not particularly limited, but in the present invention, a cylindrical shape is optimal, and the present invention is effective with a cross-sectional diameter of 3 mm or more, particularly 5 mm or more,
Ideal for 20mm or less.

Further, the length of the source gas introducing means is such that when a voltage is applied to the source gas introducing means, an electric field is uniformly applied to the substrate, and the source gas is uniformly distributed on the surface of the substrate exposed to plasma. Any length may be used, but usually the length of the base or about 0.1 to 50 mm longer than that is used.

Further, as the direction of release of the gas release holes provided in the raw material gas introduction means, one having a plurality of directions is preferable, and preferably the direction of the base or the direction of spreading over the entire discharge space is suitable. . Alternatively, the material itself may be porous and can uniformly introduce gas in all directions.

In the apparatus of the present invention, the electric field generated between the source gas introducing means and the substrate is preferably a DC electric field, and the direction of the electric field is more preferably directed from the source gas introducing means to the substrate. Further, the magnitude of the DC voltage applied to the source gas introducing means for generating a DC electric field between the source gas introducing means and the substrate is suitably 15 V or more and 300 V or less, preferably 30 V or more and 200 V or less. Further, there is no particular limitation on the DC voltage waveform applied to the source gas introducing means for generating a DC electric field. In other words, as long as the direction of the voltage does not change with time, it may be any case.For example, not only a constant voltage whose magnitude does not change with time, but also a magnitude changes with a panel-like voltage and time rectified by a rectifier. I do. The present invention is also effective with a pulsating voltage.

Applying an AC voltage is also effective in the present invention. In this case, there is no problem with the AC frequency, and it is preferable that the frequency be 20 Hz or more. In practice, 50 Hz or 60 Hz for a low frequency and 13.56 MHz for a high frequency are suitable. The AC waveform may be a sine wave, a rectangular wave, or any other waveform, but a sine wave is suitable for practical use. However, at this time, the voltage refers to an effective value in any case.

The following effects have been clarified by such a device of the present invention.

In the apparatus of the present invention having the above configuration, since the source gas introduction means is in the discharge space, the introduced source gas is excited, decomposed, and the like by microwave power until it reaches the substrate. In this way, electrons having a large energy accelerated by the electric field are present mainly in the gas introducing means, so that excitation, decomposition and the like are performed smoothly and sufficiently. For this reason, the utilization efficiency of the source gas is greatly improved.

On the other hand, when the source gas reaches the substrate, it is a sufficiently decomposed precursor, has high energy, and has high surface mobility on the substrate, so that a deposited film with low internal stress is formed.

Furthermore, after the source gas is introduced by applying a voltage to the source gas introducing means itself, the ions ionized by the plasma are sufficiently accelerated by the electric field, and bombard the substrate with a large kinetic energy. For this reason, even if the voltage on the source gas introducing means is relatively low, the deposited film can be sufficiently annealed locally, and the stress in the film can be reduced and defects can be reduced. can do.

When film deposition was performed using the apparatus of the present invention, a more remarkable effect was obtained when the internal pressure of the reaction vessel was 100 mTorr or less, more preferably 50 mTorr or less.

As the material gas for the deposited film used in the apparatus of the present invention, for example, a material gas for forming an amorphous silicon such as silane (SiH ₄ ) or disilane (Si ₂ H ₆ ), or a gas for forming another functional deposited film such as germane (GeH ₄ ) A raw material gas or a mixed gas thereof is used.

Examples of the dilution gas include hydrogen (H ₂ ), argon (Ar), helium (He), and the like.

Elements that include nitrogen atoms such as nitrogen (N ₂ ) and ammonia (NH ₃ ), oxygen (O ₂ ), nitrogen oxide (NO),
An element containing an oxygen atom such as nitrous oxide (N ₂ O), methane (C
H _4), ethane (C ₂ H _6), ethylene (C ₂ H _4), acetylene (C ₂ H _2), hydrocarbons such as propane (C ₃ H _8), silicon tetrafluoride (SiF _4), six Examples include fluorinated compounds such as disilicon fluoride (Si ₂ F ₆ ) and germanium tetrafluoride (GeF ₄ ), or a mixed gas thereof.

The present invention is similarly effective when dopant gases such as diborane (B ₂ H ₆ ), boron fluoride (BF ₃ ), and phosphine (PH ₃ ) are simultaneously introduced into the discharge space for doping.

As the base material, for example, stainless steel, Al, Cr, Mo, A
Metals such as u, In, Nb, Te, V, Ti, Pt, Pd, Fe, alloys of these, or synthetic resins such as polycarbonates whose surfaces are conductively treated, glass, ceramics, paper, and the like are commonly used in the present invention. .

Although any substrate temperature is effective when forming a deposited film using the apparatus of the present invention, a temperature of 20 ° C. or more and 500 ° C. or less, preferably 50 ° C. or more and 450 ° C. or less is desirable because a good effect is exhibited.

Further, as a method for introducing the microwave of the apparatus of the present invention to the response container, a method using a waveguide or a coaxial cable may be mentioned, and the introduction into the reaction container may be performed through one or a plurality of dielectric windows, or There is a method of installing an antenna in a furnace. At this time, the material of the microwave introduction window into the reaction vessel may be a material with less microwave loss, such as alumina, aluminum nitride, boron nitride, silicon nitride, silicon carbide, silicon oxide, beryllium oxide, Teflon, and polystyrene. Is usually used.

Further, the present invention can be applied to the manufacture of any device other than a photoconductor for a copying machine or a printer such as a blocking type amorphous silicon photoconductor and a high resistance type amorphous silicon photoconductor.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.

Example 1, Comparative Example 1 Using the microwave plasma CVD apparatus of the present invention shown in FIG. 1 and the conventional microwave CVD apparatus shown in FIG. 3
An electrophotographic photosensitive member composed of the layers was prepared. The conditions for producing the electrophotographic photoreceptor are as follows: the applied DC voltage of the photosensitive layer is from -300 V to +30.
The voltage was changed to 0 V, and the other conditions were the same as those shown in Table 1. The voltage is applied to the source gas introducing means in the embodiment using the apparatus shown in FIG. 1, and is applied to the electrodes in the comparative example using the apparatus shown in FIG.

The charging ability, sensitivity and deposition rate of the electrophotographic photoreceptor thus manufactured were measured by the following methods.

(1) established the chargeability V _d deposited film charging exposure experimental apparatus, 0.2Se at 6.3KV
Perform corona charging during c. At this time, the surface potential of the dark portion of the deposited film is measured by a surface voltmeter.

(2) the residual potential V _R deposited film is charged to a certain dark portion surface potential, and immediately controls the optical image. The light image was irradiated with a fixed amount of light excluding light in the wavelength range of 550 nm or less using a filter using a xenon lamp light source. At this time, the bright portion surface potential of the deposited film is measured by a surface voltmeter.

(3) Deposition rate D _{R The} thickness of the deposited film is measured with a film thickness measuring device, and the deposition rate D _R is measured.
Ask for.

The results obtained by such a measurement method are shown as the surface potential characteristics of the electrophotographic photoreceptor. FIG. 6 shows the charging ability, FIG. 7 shows the residual potential, and FIG. 8 shows the deposition rate.

In the figure, the abscissa indicates the voltage applied to the photosensitive layer when the electrophotographic photosensitive member was manufactured, and the ordinate indicates the measured values of the electrophotographic photosensitive member manufactured in the comparative example and the electrophotographic photosensitive member manufactured in the example. Are expressed as relative values.

In both the examples and comparative examples, the DC voltage was 30
When a value larger than 0 V was applied, abnormal discharge such as sparks occurred, and deterioration of the film quality and remarkable decrease in reproducibility were observed.

Further, the following evaluation was performed on the results obtained from Example 1 and Comparative Example 1.

The DC applied voltage V in Comparative Example 1, which can obtain values equivalent to the values of the charging ability, residual potential, and deposition rate obtained when the applied DC voltage is 20 V and 100 V in Example 1, is obtained. Table 2 shows the results.

In order to obtain the same electrical characteristics as in the case of the applied DC voltage of 20 V in the apparatus of the present invention, the DC voltage is reduced by about 25
0V must be applied. On the other hand, regarding the deposition rate,
It is necessary to apply a voltage of 300 V or more, and the difference between the device of the present invention and the conventional device has become more apparent.

Further, with respect to the value when a voltage of 100 V was applied in the apparatus of the present invention, 300 V or more was required for both the electrical characteristics and the deposition rate. However, when a voltage higher than 300 V was applied, abnormal discharge such as sparks occurred, and the reproducibility was remarkably deteriorated, for example, the film characteristics were significantly degraded, so that accurate values could not be obtained.

From these results, the microwave plasma CVD of the present invention
It was confirmed that the apparatus had a remarkable effect on the improvement of the charging ability, the residual potential and the deposition rate as compared with the conventional microwave plasma CVD apparatus at any applied DC voltage.

In particular, when a positive DC voltage is applied to the gas introduction means,
Compared with the deposited film produced by the conventional apparatus, the characteristics were greatly improved. Furthermore, a remarkable effect was confirmed when the value of the positive applied DC voltage was 15 V or more, and more preferably 30 V or more.

Comparative Example 2 A deposited film was formed using the conventional microwave plasma CVD apparatus shown in FIG. 5 under the conditions shown in Table 1 in the same manner as in Comparative Example 1 and Example 1. At this time, a plurality of substrates were placed in a vacuum reactor, and the distance between the substrates was set to a maximum of 300 mm. In addition, about the produced deposited film, similarly to Comparative Example 1 and Example 2,
When the charging ability, the residual potential and the deposition rate were measured, non-uniformity occurred in the charging ability, the residual potential and the deposition rate. That is, non-uniformity of the characteristics was observed on the upstream side (source gas inlet side) and downstream side (source gas exhaust means side) of the source gas.

Example 2 Using the deposited film forming apparatus according to the present invention shown in FIG.
A deposited film was produced under the conditions shown in Table 1 as in the comparative example. The charging ability, sensitivity and deposition rate of the produced deposited film were measured in the same manner as in the comparative example, and the following evaluation was performed.

(1) Non-uniformity 1-a Charging power ΔV _d = V _{d max} (maximum charging power in deposited film) −V _MIN (minimum charging power in deposited film) 1-b sensitivity ΔV (in the deposited film, the value of the maximum of the light portion surface conductive _{position) L = V L max -V MIN} ( in the deposited film, the minimum light portion surface potential) 1-c deposition rate ΔD _R = D _{R max} (deposited film shows in the maximum rate of deposition) -D _{R min} (deposited film, a minimum deposition rate) the results in table 3.

In addition, in Table 3, for comparison, the value of the example when the value obtained in the comparative example is set to 100 is shown in percentage. That is, the value obtained in the example / the value obtained in the comparative example × 100 (%) From these results, the microwave plasma CV according to the present invention was obtained.
The D device is compared to the conventional microwave plasma CVD device,
For example, it has been confirmed that there is a remarkable effect in obtaining uniformity of film thickness and film quality in manufacturing a device requiring a large area such as an electrophotographic photoreceptor.

Example 3 Using the conventional microwave plasma CVD apparatus shown in FIG. 4 and the microwave plasma CVD apparatus according to the present invention shown in FIG. 1, a deposition film was produced by changing the flow rate of source gas.

At this time, the charge injection blocking layer and the surface protective layer were manufactured under the film forming conditions shown in Table 1, and were manufactured by changing the flow rate of the raw material gas for the photosensitive layer.

When the charging ability, the residual potential and the deposition rate of the deposited film thus produced were evaluated, the results shown in FIGS. 9, 10 and 11 were obtained.

In FIG. 9, the abscissa represents the flow rate of silane gas (SiH ₄ ) at the time of forming the photosensitive layer, and the ordinate represents the deposited film produced by using the apparatus of the present invention shown in FIG. It shows the value when the potential of the dark area surface at the developing position when charged is defined as the charging ability. At this time, 100% on the vertical axis indicates the charging ability of the deposited film produced at the same flow rate of the silane gas when the conventional apparatus of FIG. 4 was used.

In FIG. 10, the horizontal axis represents the flow rate of the silane gas at the time of forming the photosensitive layer, and the vertical axis represents the constant dark area surface potential applied to the deposited film produced by using the apparatus of the present invention shown in FIG. The value when the surface potential at this time is taken as the residual potential is shown. At this time, 100% on the vertical axis indicates the residual potential of the deposited film produced at the same silane gas flow rate when the conventional apparatus of FIG. 4 was used.

In FIG. 11, the horizontal axis represents the flow rate of the silane gas during the formation of the photosensitive layer, and the vertical axis represents the deposition rate of the deposited film produced using the apparatus of the present invention shown in FIG. At this time, 100% on the vertical axis indicates the deposition rate of the deposited film produced at the same silane gas flow rate when the conventional apparatus of FIG. 4 was used.

From these results, charging ability,
It was confirmed that the deposited film forming apparatus of the present invention was similarly effective in improving characteristics such as residual potential. In particular, when the flow rate of the source gas was 400 sccm or more, a remarkable effect was observed in improving the deposition rate.

Example 4 A deposited film was produced using the conventional microwave plasma CVD apparatus shown in FIG. 4 and the microwave plasma CVD apparatus according to the present invention shown in FIG. 1 while changing the internal pressure.

At this time, the charge injection blocking layer and the surface protective layer were manufactured under the film forming conditions shown in Table 1, and were manufactured by changing the internal pressure in the photosensitive layer.

When the charging ability, residual potential and deposition rate of the deposited film thus produced were evaluated, the results shown in FIGS. 12, 13 and 14 were obtained.

In FIG. 12, the horizontal axis represents the internal pressure at the time of forming the photosensitive layer, and the vertical axis represents the value obtained when the deposited film produced during use of the apparatus of the present invention shown in FIG. The value when the surface potential of the dark part is defined as the charging ability is shown. At this time, 100% on the vertical axis indicates the charging ability of the deposited film formed at the same internal pressure and voltage when the conventional apparatus of FIG. 4 was used.

In FIG. 13, the horizontal axis indicates the internal pressure during the formation of the photosensitive layer, and the vertical axis indicates the case where a constant dark area surface potential is applied to the deposited film produced using the apparatus of the present invention shown in FIG. Are shown when the surface potential of the sample is regarded as the residual potential. At this time, the vertical axis
100% indicates the residual potential of the deposited film produced at the same internal pressure and voltage when using the conventional apparatus shown in FIG.

In FIG. 14, the horizontal axis represents the internal pressure during the formation of the photosensitive layer, and the vertical axis represents the deposition rate of the deposited film produced when using the apparatus of the present invention shown in FIG. At this time, 100% on the vertical axis indicates the deposition rate of the deposited film produced at the same internal pressure when using the conventional apparatus of FIG.

From these results, it was confirmed that the effect of the deposited film forming apparatus of the present invention was more remarkable as the internal pressure was lower than that of the conventional apparatus.

In particular, when the internal pressure at the time of forming the photosensitive layer is 100 mTorr or less, the deposited film produced by the apparatus of the present invention has a large improvement in electrophotographic characteristics, such as charging ability and residual potential, as compared with the deposited film produced by the conventional apparatus. The deposition rate was also improved.

Further, when the internal pressure was 50 mTorr or less, the improvement of the characteristics and the improvement of the deposition rate became remarkable, and even at a pressure lower than that, a certain effect was recognized as it was.

[Summary of Effect of the Invention] A gas introduction means also serving as an electrode is provided in a discharge space, and a deposited film formed by a microwave plasma CVD apparatus installed so as to apply an electric field between the electrode and a substrate is formed by a conventional microwave. As compared with the microwave plasma CVD apparatus, those formed at any position on the substrate have better characteristics. The reason for this is that the introduced source gas is sufficiently excited and decomposed by plasma until it reaches the substrate because it is a gas introduction means also serving as an electrode, and an electric field is applied simultaneously with the introduction of the source gas. Charges are gathered around the source gas introduction means, the excitation speed is high, the precursor is sufficiently decomposed, the energy is high and the surface mobility on the substrate is high, so a deposited film with low internal stress and good characteristics can be obtained. It is thought to be formed.

For this reason, the microwave plasma CVD apparatus of the present invention can not only produce a deposited film on a substrate with high efficiency and high uniformity of use of the source gas, but also mainly use amorphous silicon produced by the microwave plasma CVD apparatus of the present invention. The photosensitive drum using the photoreceptor achieved a great improvement in the charging ability and a great decrease in the residual potential as compared with the conventional microwave plasma CVD apparatus.

Further, the present invention can provide more effective effects even in a microwave plasma CVD apparatus surrounded by a cylindrical substrate as shown in FIG. 5, and can cope with high-speed copying machines and downsizing of photoconductors. It was possible to mass-produce photosensitive drums at a high speed and at a low cost, which is excellent, has a wide latitude in setting the position of the charger and the developing device, and is very easy to use.

[Brief description of the drawings]

1, 2 and 3 show a microwave plasma CV according to the present invention.
Figures 4 and 5 show a conventional apparatus for forming a deposited film by a microwave plasma CVD method. 3 (A) and 3 (B) show the same device in two cross sections, and show a longitudinal sectional view and a transverse sectional view, respectively. FIGS. 6, 7 and 8 are graphs (FIG. 6) showing the relationship between the applied DC voltage (V) and the charging ability (V _d ) of the deposited film in Example and Comparative Example 1, respectively. applying a direct current voltage (V) and the deposited film residual potential (V _R) and a graph showing the relationship of (Figure 7) and a graph showing the relationship between an applied DC voltage (V) and film deposition rate of the deposited film (8 Figure). FIGS. 9, 10 and 11 are graphs (FIG. 9) showing the relationship between the charging ability of the deposited film and the flow rate of the SiH ₄ gas in Example 3, respectively, and the residual potential of the deposited film and the flow rate of the SiH ₄ gas. (FIG. 10) and a graph (FIG. 11) showing the relationship with the film deposition rate of the deposited film. 12, 13 and 14 are graphs (FIG. 12) showing the relationship between the charging ability of the deposited film and the internal pressure during film formation in Example 4, respectively, and the residual potential of the deposited film and the time during film formation. 13 is a graph showing the relationship between the internal pressure of the deposited film (FIG. 13) and the graph showing the relationship between the film deposition rate of the deposited film and the internal pressure during film formation (FIG. 14). In the figure, 101, 201, 301, 401, 501...
02,302,402,502 …… Microwave introduction window, 103,203,303,40
3,503 ... waveguide, 104, 204, 304, 404, 504 ... exhaust pipe, 10
5,205,405,505 …… base, 305 …… cylindrical base, 106,206,
306, 406, 506 ... discharge space, 107, 207, 407, 507 ... substrate holder, 307 ... heater, 108, 208, 308, 408, 508 ... gas introduction means, 109, 209, 309, 409, 509 ... power supply, 410, 510 ...
... electrodes, 311 ... rotation mechanism.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C23C 16/50

Claims (4)

(57) [Claims] 1. A reaction vessel having a discharge space capable of being vacuum-tight and having a discharge space, a mechanism for disposing a substrate on which a deposited film is formed in the reaction vessel, and a raw material for introducing a raw material gas into the discharge space. A glow discharge configured by gas introduction means and microwave introduction means for introducing microwaves into the discharge space, introducing a raw material gas and microwave energy into the discharge space, and being excited by the introduced microwave energy. According to the microwave plasma CVD apparatus for forming a deposited film on the substrate, the source gas introduction means has a cylindrical shape formed of a conductive material, at least a part of the source gas introduction means The source material is located in the discharge space along a substrate disposed in the reaction vessel, and an electric field is applied between the substrate and the source gas introducing means. The power on the conductive material portions of the scan introducing means is connected a microwave plasma CVD apparatus according to claim. 2. The microwave plasma CVD apparatus according to claim 1, wherein said source gas introducing means has a length equal to or longer than the length of said base by 0.1 to 50 mm. 3. The microwave plasma according to claim 1, wherein said source gas introducing means has a large number of gas outlets.
CVD equipment. 4. The microwave plasma CVD apparatus according to claim 1, wherein said source gas introducing means has a cylindrical shape.