JP3368137B2 - Apparatus and method for forming deposited film - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deposited film, particularly a functional deposited film, on a cylindrical conductive substrate, particularly a semiconductor device, a photoreceptive member for electrophotography, an image input line sensor, an imaging device, and a photovoltaic device. The present invention relates to an apparatus and method for forming a deposited film by plasma CVD for forming an amorphous semiconductor, which is used for the above.

[0002]

2. Description of the Related Art In the field of image formation, a photoconductive material for forming a light receiving layer in a light receiving member has high sensitivity,
The SN ratio [photocurrent (Ip) / dark current Id)] is high, the absorption spectrum is suitable for the spectral characteristics of the electromagnetic wave irradiated, the photoresponsiveness is fast, and the desired dark resistance value is obtained. Harmless to the human body,
Such characteristics are required. Particularly, in the case of an electrophotographic light receiving member incorporated in an electrophotographic apparatus used in an office as an office machine, the pollution-free property at the time of use is an important point. As a material that can satisfy such requirements, there is an electrophotographic light-receiving member using amorphous silicon (a-Si). For example, patent application publication Sho 54
JP-A-86341 discloses a technique relating to a photoreceptive member for electrophotography, which uses a-Si for a photoconductive layer and is excellent in moisture resistance, durability and electric characteristics. In addition, in Japanese Patent Application Laid-Open No. 62-168161, a surface layer is
A technique using a material composed of an amorphous material containing silicon atoms, carbon atoms, and hydrogen atoms of 41 to 70 atomic% as constituent elements is described. With such technology, electrical, optical and photoconductive characteristics, and usage environment characteristics and durability are improved, and further image quality can be improved.
The electrophotographic light-receiving member composed of a-Si has been put to practical use.

On the other hand, a high level of technology is required to manufacture a light-receiving member for a-Si electrophotography. Particularly, in the case of a light-receiving member for electrophotography, it is required to have a large area and a thick film thickness as compared with other devices. Therefore, how to ensure uniformity and a-Si film deposition An important factor is how to prevent the abnormal growth of the film, which is generated by foreign matter as a nucleus. From such a point of view, various proposals have been made on how to industrially produce a high-quality photoreceptive member for a-Si electrophotography.
In particular, with respect to the light receiving member for electrophotography, the occurrence of spherical projections, which cause image defects called so-called "white spots", in which fine white spots occur on a copy image, poses a problem. It is considered that most of the causes of such spherical protrusions are abnormal growth of the film caused by the debris caused by the film peeling generated inside the deposited film forming apparatus during the deposition film formation to adhere to the surface of the substrate.

Further, unevenness in which the image density changes depending on the part on the copy image obtained by the electrophotographic apparatus poses a problem, and therefore proposals for improvement have been made. For example, Japanese Patent Application Laid-Open No. 4-4183871 discloses a technique in which a microwave introduction unit is composed of two different regions in a deposited film forming apparatus. According to the publication,
The permittivity (ε) and the dielectric contact (t) at the microwave frequency using the surface of the microwave introducing means in contact with the plasma.
By setting the product of an δ) to 2 × 10 ⁻² or less, it is possible to stabilize the discharge and prevent the peeling of the deposited film. As a result,
It is said that the uniformity of the deposited film can be improved and the occurrence of image defects can be suppressed. As the most suitable method, a technique of coating the alumina ceramics with a plasma spraying method for the microwave introducing means is mentioned. By such a technique, it becomes possible to form a high-quality deposited film with a small number of spherical protrusions.

[0005]

However, in recent years,
Electrophotographic devices are required to have higher image quality, higher speed, and higher durability than ever before. Furthermore, in order to reduce the service cost, it is necessary to reduce the maintenance frequency by improving the reliability of each component. Under these circumstances, the electrophotographic light-receiving member can be used repeatedly for a long time under various circumstances without requiring maintenance by a service person. Under such circumstances, there is room for improvement in the conventional electrophotographic light-receiving member. For example, in a device having a conventional high-frequency introducing means, depending on the conditions, minute “white spots” due to the spherical protrusions described above may occur, and
In some cases, image density unevenness also occurs depending on the conditions. Such an image defect has not been a problem in the past, but further improvement has been required as the image quality, the speed, and the durability are increased.

Therefore, the present invention solves the above-mentioned problems in the conventional one, suppresses the abnormal growth of the deposited film, reduces the occurrence of spherical projections that cause image defects, and improves the electron quality of the image. It is an object of the present invention to provide a deposited film forming apparatus and method capable of supplying a light receiving member for photography. Another object of the present invention is to provide a deposited film forming apparatus and method capable of preventing localization of plasma and supplying a highly homogenized electrophotographic light-receiving member over the entire surface. Is.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a deposited film forming apparatus and method as follows. That is, in the deposited film forming apparatus of the present invention, a plurality of cylindrical conductive bases are rotatably arranged on the same circumference in a vacuum-tight reaction container, and the cylindrical conductive bases are arranged within the circumference. A raw material gas is introduced into the raw material through the raw material gas introduction means and a high frequency power is introduced through the high frequency power means, a glow discharge is caused by the high frequency power, and a deposited film is formed on the cylindrical conductive substrate. In the film forming apparatus, the high-frequency power introducing means has an insulating material as a base material, and a metal material having a sufficient thickness for transmitting the high-frequency power in a region separated from a glow discharge region by the insulating material. Is closely formed with the insulating material. And, in the above device of the present invention, the insulating base material,
It can be formed of a ceramic material. Further, the above apparatus of the present invention may be configured such that the high-frequency introducing means is provided with a cooling mechanism or a heating mechanism. Further, in the above apparatus of the present invention, the high frequency introducing means may also serve as the raw material gas introducing means. Also,
In the above-mentioned device of the present invention, the surface roughness of at least a portion of the insulating base material which is in contact with glow discharge is 2.5 cm.
10-point average roughness with a reference length of 5 μm to 200 μm
It is preferable to set it as the range. Further, in the deposited film forming method of the present invention, a plurality of cylindrical conductive substrates are rotatably arranged on the same circumference in a vacuum-tight reaction container, and the cylindrical conductive substrates are arranged within the circumference. In the deposited film forming method, in which a source gas and high frequency power are introduced, a glow discharge is generated by the high frequency power, and a deposited film is formed on the cylindrical conductive substrate, the high frequency power is introduced by an insulating material. Introduced by a high-frequency power introducing means in which a metal material having a sufficient thickness for transmitting the high-frequency power is closely formed as a base material in a region separated from the glow discharge region by the insulating material. It is characterized by forming a deposited film. And in the said method of this invention, the frequency of the said high frequency electric power is 20 MHz-
It is preferably in the range of 450 MHz. Also, in the above method of the present invention, the high frequency introducing means may be cooled or heated.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, as described above, a spherical projection is generated by forming an electrode with an insulating material as a base material in a region separated from the glow discharge region by the insulating material. Can be further suppressed, and unevenness in image density can be essentially prevented. As described above, the present invention is capable of suppressing "white spots" due to the generation of spherical projections and making the characteristic unevenness of the electrophotographic light-receiving member uniform, which are difficult to achieve by the mechanism of the conventional high-frequency introducing means. , Which are compatible with each other at a high level, but by the above-mentioned configuration of the present invention, the generation of a gap between the insulating material and the electrode is eliminated, and the surface of the electrode is coated with an insulating material as compared with the case of coating. It is based on increasing the strength of the insulating material itself.

And, it was completed by the following process. One of the factors that influence the yield in the electrophotographic light-receiving member is the occurrence of the spherical projections described above. To prevent the generation of the spherical projections, it is possible to coat the alumina ceramics or the like by the plasma spraying method or the like as described above. Ceramics have a larger surface energy than metals, and therefore have a stronger adhesive force with the deposited film, and thus were effective as a means for preventing film peeling. However, even if such a coating is applied to the high frequency introducing means, the effect is not always sufficient. On the surface of the high-frequency introducing means, a film is deposited under the condition that the temperature is higher than that of the normal substrate surface, and further self-bias is generated by the high-frequency power, which causes excessive ion bombardment, so that stress strain is accumulated and the deposited film Peeling occurs. Further, such a tendency tends to appear more remarkably as the high frequency power applied to the electrode increases. Under these conditions, film peeling may occur even when the surface of the electrode is coated with, for example, alumina ceramics by plasma spraying. On the other hand, in order to improve the adhesion of the deposited film, the adhesion of the film can be further improved by increasing the roughness (surface roughness) of the surface of the electrode (the surface of the coating material). However, in the case of plasma spraying,
When the particle diameter of the thermal spray material is increased to increase the surface roughness, the porosity becomes extremely large, so that the binding force of the coating layer decreases and the coating layer itself may peel off.

From such a background, the present inventor has studied a method of providing a cover made of a ceramic material on the surface of the electrode. However, it has been found that when such a cover is used, the uniformity of the characteristics of the deposited film may be impaired. According to the knowledge of the present inventor, it has been found that such non-uniformity of the characteristics is caused by a gap formed between the electrode and the cover made of the ceramic material. There are still many unclear points about the relationship between the non-uniformity of the characteristics and the electrode and the ceramic cover, but it is presumed that the mechanism is as follows. Generally, transmission of high frequency power is performed in a dielectric portion between conductors. In the case of the structure of the deposited film generating apparatus of the present invention, it can be regarded as a coaxial structure with the electrode as the center and the cylindrical substrate as the outer conductor. In this case, the space between the electrode and the ceramic cover is so small that it can be ignored with respect to the space between the base (outer conductor) and the electrode (center conductor). On the other hand, when glow discharge is generated, plasma is considered to act as a kind of conductor, so the impedance of the load largely depends on the condition of the sheath region formed around the electrodes. In this case, the influence of the gap between the electrode and the ceramic cover cannot be ignored. Under these circumstances, the discharge is greatly affected by the variation in the gap between the electrode and the ceramic cover. For example, if the gap is not uniform due to machining problems, the electric discharge may be largely biased. In addition, when the temperature of the electrode rises during glow discharge, the size of the gap changes due to the thermal expansion of the electrode, so that the matching condition may change greatly. Such bias or fluctuation of the discharge not only leads to unevenness in the characteristics of the electrophotographic light-receiving member, but also causes a film that is easily peeled off to be deposited on the surface of the cover made of a ceramic material, which may lead to the generation of spherical protrusions. Further, such a tendency tends to be more remarkable as the high frequency power and the frequency increase. It is practically difficult to eliminate the gap between the electrode and the cover as described above. For example, when thermal expansion occurs in the electrode, it is necessary to provide a gap to some extent due to the difference in thermal expansion coefficient between the ceramic material and the electrode. Also, regarding mechanical fitting, a ceramic material has a lower toughness than a metal, so that it often leads to damage unless a certain gap is provided. Therefore, it is a design principle to set an appropriate gap between the electrode and the ceramic cover. On the other hand, according to the study by the present inventor, the smaller the gap, the larger the discharge unevenness. Also, as the gap is increased, the loss of high frequency power increases.

For the reasons described above, it is difficult for the conventional mechanism of the high-frequency introducing means to achieve both high level suppression of "white spots" and uniformity of characteristic unevenness of the electrophotographic light-receiving member. It was The present invention has been completed based on the above analysis. That is, in the high-frequency power introducing means used in the present invention, the insulator is used as the base material and the electrodes are formed in close contact therewith (the region separated from the glow discharge region), so that the above-mentioned gap does not exist. Further, the strength of the insulating material itself is higher than that when the surface of the electrode is coated with the insulating material. Therefore, the uneven discharge can be essentially prevented, and the spherical protrusion due to the peeling of the coating material can be effectively prevented.

The contents of the present invention will be described in detail below with reference to the drawings. The high-frequency introducing means used in the present invention has a structure in which at least an insulator is used as a base material and a metal material (electrode) capable of transmitting high-frequency power is closely formed in a region separated from the glow discharge region by the insulator. As the base material, an insulator material having good adhesion of deposited film, specifically, alumina ceramics, aluminum nitride, boron nitride, zircon, cordierite, zircon cordierite, silicon nitride, beryllium oxide, mica Ceramics, quartz glass, Pyrex glass, etc. can be used. The shape of the insulator and the electrode as the base material is preferably a cylindrical shape (or a cylindrical shape) from the viewpoints of workability and ease of forming the electrode. In addition, it is desirable to arrange the insulator and the electrodes on concentric circles for the same reason. Further, at least the surface of this insulator that is in contact with the discharge space can be provided with irregularities mainly for the purpose of preventing film peeling of the deposited film. In this case, the size of the unevenness is 2.5 mm
10 μm average roughness (Rz) with reference length of 5 μm or more 2
The range of 00 μm or less is preferable. The means for providing the surface with irregularities is not particularly limited, but for example, blasting for blowing a projectile is practically preferable. There is no particular limitation on the size of the insulator as the base material. However, when a plurality of cylindrical conductive bases are arranged on the same circumference and the source gas introduction device / electrode is installed within the arrangement circle of the cylindrical conductive bases, the size of the cylindrical insulator ( That is, the overall diameter of the cylindrical or cylindrical high-frequency introducing means is preferably about 4 to 25% of the diameter of the circumference on which this substrate is arranged. The thickness of the cylindrical insulator is also not particularly limited, but it is 0.5 due to problems in processing and mechanical strength.
It is practically about 20 mm. Further, the diameter of the cylindrical (or cylindrical) electrode itself is not particularly limited as long as the diameter and the thickness of the above-mentioned insulator are satisfied. Practically, a diameter of 2 mm or more is desirable.

The length of the high frequency introducing means is preferably in the range of about 100 to 150% with respect to the length of the substrate. However,
Even if the length is less than 100% with respect to the substrate, there is no problem in obtaining the effect of the present invention. The length of the high frequency introducing means referred to here means a portion having a function of substantially radiating a high frequency into the discharge space. Any material can be used as long as the material of the electrode is conductive, but Al, C
r, Cu, Mo, Au, Ag, In, Nb, Ni, T
In addition to metals such as e, V, Ti, Pt, Pb, and Fe, alloys thereof such as stainless steel can be used. Any method may be used for forming these materials in close contact with the insulator serving as the base material, and examples thereof include plasma spraying method, plating method, brazing method, plasma CVD method, sputtering method, and vacuum deposition method. Etc. can be used. In practice, it is desirable to select one of these methods that matches the characteristics of the material used as the electrode. The thickness of the electrode may be any thickness that can transmit high frequency power. That is, this thickness may be a thickness greater than the skin effect determined by the frequency of the high frequency power used and the material of the electrode. For example, when the frequency of the high frequency power is 105 MHz and the material of the electrodes is copper (Cu), the notation effect is in the range of about 7 μm. Therefore, in this case, the thickness of the electrode may be 7 μm or more. On the other hand, when the temperature rise of the electrode is large, if the thickness of the electrode is large, the peeling of the electrode may occur due to the difference in the coefficient of thermal expansion of the insulator serving as the base material. Therefore, it is desirable that the upper limit of the thickness of the electrode be determined by the conditions at the time of forming the deposited film.

A cavity is formed inside the high-frequency introducing means (that is, on the side separated from the glow discharge region) by a combination of the size (diameter) and thickness of the insulator and the thickness of the electrode. The cavity may be held in vacuum or separated from the vacuum system by a vacuum seal. In any case, it is desirable that the raw material gas does not flow into the interior in order to avoid the retention of the raw material gas. It is also possible to fill the cavities with padding. In this case, as the material of the filling material, in addition to the insulating material which is the material of the insulator which is the base material of the high frequency introducing means, the metallic material which is the material of the electrode can be used. These fillers may be in close contact with the surface of the electrode on the cavity side or may have a gap therebetween. Particularly when thermal expansion or the like becomes a problem, an appropriate gap (about 0.1 mm to 5 mm) can be provided.
Also in this case, since the high frequency power propagates only to the electrodes, this gap does not impair the effect of the present invention.

The number of high frequency introducing means may be one or plural. If there is only one high-frequency introduction means,
From the viewpoint of ensuring uniformity, it is desirable that the cylindrical conductive substrate is placed coaxially with the center of the arrangement circle. When a plurality of high-frequency introducing means are provided, it is desirable that each high-frequency introducing means be arranged on the circumference of a circle concentric with the arrangement circle of the base. When the high-frequency introducing means is two, the high-frequency introducing means may be divided into two in the generatrix direction (drawing direction). In this case, it is desirable that the position of the high frequency introducing means is set at the center of the arrangement circle of the base as described above. In each case, the respective high frequency introducing means are arranged within the arrangement circle of the base body. Further, in the present invention, when the means for heating or cooling the high frequency introducing means is provided, the high frequency introducing means is controlled to a desired temperature to improve the adhesion between the insulator serving as the base material and the deposited film, and to remove the film. This can be prevented more effectively. Whether the high-frequency introducing means is cooled or heated depends on the combination of the deposited film material and the insulating material as the base material, high-frequency power, pressure,
Determined by conditions such as the flow rate of raw material gas. Further, in the present invention, the high frequency introducing means and the raw material gas introducing means can be combined. In this case, it is desirable that the source gas is discharged into the discharge space through the source gas passage formed inside the insulator and through the gas discharge hole formed in the insulator.

In the present invention, the source gas is decomposed by applying the high frequency power to the high frequency introducing means. The frequency of the high frequency power that can be used in the present invention is not particularly limited,
According to the inventor's experiment, when the frequency is less than 20 MHz, the discharge may become unstable depending on the conditions, and the conditions for forming the deposited film may be limited. On the other hand, if it is higher than 450 MHz, the transmission characteristic of high frequency power may be deteriorated, and in some cases, it may be difficult to generate glow discharge itself. Therefore, the frequency range of 20 MHz to 450 MHz is optimal for the present invention. Any high-frequency waveform may be used, but a sine wave, a rectangular wave, or the like is suitable. The magnitude of the high-frequency power is appropriately determined according to the characteristics of the target deposited film, etc., but is 10 per substrate.
~ 5000W is desirable, and more preferably 20-2000W.

The deposited film forming apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic diagram of a cross section in the generatrix direction (drawing direction) of an example of the high-frequency introducing means of the present invention having a cylindrical shape.
In the example of FIG. 1, the high frequency introducing means 102 is composed of a cylindrical insulator 111 and an electrode 112. The outer side of the insulator 111 is a glow discharge region, and a region separated from the glow discharge region is formed inside. Further, the electrode 112 is an insulator 1.
It is formed in close contact with the inner surface of 11 (that is, the surface on the side of the region separated from the glow discharge region). In addition, a cavity 113 is formed inside the high-frequency introducing means (further inside the electrode), and is separated from the vacuum system by a vacuum seal (not shown) so that the raw material gas does not flow in. Further, the electrode 112 is connected to a high frequency introduction terminal (not shown) at the upper part, and high frequency power is applied from a high frequency transmission circuit (not shown). In the example of FIG. 1, the lower end of the insulator serving as the base material (the end on the side to which the high frequency introduction terminal is not connected) is closed, but the present invention is not limited to this, and both ends are opened. It may have a different shape. Further, a high-frequency transmission circuit branched in advance can be connected from both ends of the high-frequency introducing means.

FIG. 2 is a schematic diagram of a cross section in the generatrix direction (drawing direction) illustrating a cylindrical high-frequency introducing means in which an internal cavity is filled with metal. In the example of FIG. 2, the cylindrical insulator 111 and the electrode 11 are formed on the inner surface of the insulator.
2 are formed in close contact with each other, and a metal rod 115 is inserted inside thereof with a gap 114. FIG. 3 is a schematic view illustrating a cylindrical high-frequency introducing means when a cooling mechanism is provided. 3A is a cross-sectional view in the diametrical direction, and FIG. 3B is a cross-sectional view in the generatrix direction (drawing direction). In the example of FIG. 3, the cylindrical insulator 111 and the electrode 11 are formed on the inner surface of the insulator.
2 are formed in close contact with each other, and a cavity 113 is formed inside thereof. The cavity is separated from the vacuum system by a vacuum seal (not shown), and a cooling medium introduction port 119 and a cooling medium discharge port 121 are provided in the upper part, and a cooling medium introduction pipe 120 is provided inside. In the example of FIG. 3, the coolant supplied from the coolant supply device (not shown) is supplied from the coolant supply port 119 to the coolant introduction pipe 1.
After being introduced into the cavity 113 through 20 and directly cooling the electrode 112, it is discharged from the refrigerant discharge port 121. Although the case of cooling the high frequency introducing device is shown in the example of FIG. 3, the present invention is not limited to this, and when heating the high frequency introducing device, for example, a method of inserting a heater into the cavity 113 is used. Can be taken.

FIG. 4 is a schematic cross-sectional view of an example of the high frequency introducing means of the present invention when it is used also as the raw material gas introducing means.
FIG. 4A is a cross-sectional view in the diameter direction, and FIG. 4B is a cross-sectional view in the generatrix direction (drawing direction). In the example of FIG. 4, the insulator 1
An electrode 112 is closely formed on the inner surface of 11.
A raw material gas passage 118 is formed inside the insulator 111, and a desired number of raw material gas emission holes 116 are formed on the outer surface (glow discharge region side surface) of the insulator 111. And is formed through. Raw material gas inlet 11 provided at the upper end of each of the raw material gas channels 118
7 are formed. In the example of FIG. 4, the raw material gas supplied from the raw material gas introduction device (not shown) is the raw material gas introduction port 1
The material 17 flows into the raw material gas flow path 118 and is further discharged into the glow discharge region through the gas discharge hole 116.

5 (a) and 5 (b) are schematic views of an example of the deposited film forming apparatus of the present invention. This device is roughly classified into a reaction container 100 and a raw material gas supply device (not shown).
And an exhaust device (not shown) for reducing the pressure inside the reaction container 100, and a power source 107 for supplying electric power to the high-frequency introducing means 102. A cylindrical conductive substrate 101 and a substrate heating heater 10 are provided in the reaction container 100.
4. A raw material gas introduction device / electrode 102 is installed, and a power source 107 is installed on the electrode via a high frequency matching box 106.
Are connected. The base 101 is a holder (not shown)
Is held by the rotary shaft 108 via
Penetrates to the atmosphere side of the reaction container 100 through a vacuum seal (not shown) and is connected to the motor 109 via a gear 110. A raw material gas introduction means 105 is arranged in the glow discharge region 103 and is connected to a raw material gas supply device (not shown). The base 101 is arranged on the same circumference, and the glow discharge region 103 is formed in the region surrounded by the base. The number of bases may be any number as long as the discharge space can be formed, but four or more are preferable, and FIG. 1 shows an example in which eight bases are arranged. The number of the source gas introducing means 105 may be any number, but if the number is one, or the same as the number of bases, or if the number of bases is even,
Half the number of substrates is suitable. Further, the high frequency introducing means and the raw material gas supplying means as shown in FIG. 4 can be combined. The substrate 101 is heated from the inside by a substrate heating heater 104 installed in the reaction container 100. The substrate heating heater 104 may be of any vacuum type, for example, a sheath heater wound around a pipe, an electric resistor such as a plate heater or a ceramic heater, or a heat radiator such as a halogen lamp. A heating element or the like that uses a heat exchange means mediated by gas or liquid can be used. Further, these heaters for heating a substrate are provided in the reaction container 100, or a container for heating a substrate is provided separately from the reaction container and is installed therein, and the substrate is heated in advance by the container for heating a substrate, and then the reaction container is heated. Means for transporting the substrate to 100 in vacuum can also be adopted. Further, the heating of the substrate by the container for heating the substrate and the heating of the substrate in the reaction container 100 can be used together. The temperature of the substrate is appropriately selected depending on the characteristics of the target deposited film, but in the usual case, it is preferably 20 to 500 ° C, more preferably 50 to 480 ° C, and most preferably 100 to 450 ° C. Is desirable.

Next, a procedure for forming a deposited film using the apparatus shown in FIG. 5 will be described. Formation of deposited film using this device
For example, it can be performed as follows. First, the substrate 101 that has been degreased and washed in advance is installed in the reaction container 100, and the inside of the reaction container 100 is exhausted by an exhaust device (not shown) (for example, a vacuum pump). Then, while rotating the substrate 101, the temperature of the substrate 101 is controlled to a desired temperature of 20 ° C. to 500 ° C. by the heater 104. Base 101
When the temperature reaches a desired temperature, a source gas is supplied from a source gas supply system (not shown) into the internal chamber 111 through the source gas supply pipe 103. At this time, gas protrusion, etc.
Be careful not to cause extreme pressure fluctuations. Next, when the flow rate of the raw material gas reaches a predetermined flow rate, an exhaust valve (not shown) is adjusted while observing a vacuum gauge (not shown) to obtain a desired internal pressure. When the internal pressure is stable, the high frequency power supply 10
7 is set to a desired power, and high-frequency power is applied to the high-frequency electrode 102 through the high-frequency matching box 106 to cause glow discharge. This discharge energy decomposes the raw material gas introduced into the reaction vessel 100 to form a predetermined deposited film on the base 101. At this time, the substrate 101 is rotated by the motor 109 during the formation of the deposited film, so that the deposited film is formed on the entire surface of the substrate. After the desired film thickness is formed, the supply of high frequency power is stopped, the flow of the source gas into the reaction vessel is stopped, and the formation of the deposited film is completed. Due to the desired characteristics of the deposited film, when a deposited film composed of a plurality of layers is formed on the substrate, the deposited film having a desired layer constitution can be obtained by repeating the above-mentioned operation.

In the present invention, a cylindrical body is used as the substrate, but the material is usually a conductive material or a material whose surface is treated to be conductive. For example, Al, Cr, M
o, Au, In, Nb, Ni, Te, V, Ti, Pt,
In addition to metals such as Pb and Fe, alloys thereof such as stainless steel can be used. In addition, alumina ceramics, aluminum nitride, boron nitride, silicon nitride, silicon carbide, silicon oxide, beryllium oxide, quartz glass, Pyrex glass, etc., as well as synthetic resins such as polycarbonate, Teflon, etc. are used as the material whose surface is electrically conductive. it can. When a material whose surface is subjected to a conductive treatment is used as a substrate, it is desirable to conduct a conductive treatment on the side opposite to the side where the deposited film is formed.

The raw material gas used in the present invention is, for example, SiH when forming amorphous silicon.
4, silicon hydride (silanes) in a gas state such as Si2H6 or capable of being gasified is effectively used as a gas for supplying Si. In addition to silicon hydride, a silicon compound containing a fluorine atom, a so-called silane derivative substituted with a fluorine atom, specifically, silicon fluoride such as SiF4 or Si2F6, or SiH3F, SiH2F2, SiHF3 or the like. Gaseous or gasifiable substances such as fluorine-substituted silicon hydride are also effective as the Si supply gas of the present invention. In addition, if necessary, the source gas for supplying Si may be H
2, even if diluted with a gas such as He, Ar, Ne, or the like, the present invention can be used. Further, in addition to the above-mentioned gas, an atom belonging to Group 3 of the Periodic Table or an atom belonging to Group 5 of the Periodic Table can be used as a so-called dopant, if necessary. For example, when a boron atom (B) is used, B2H6, B4H10, and other borohydrides, BF
3, boron halides such as BCl3, and the like. When phosphorus atoms are used, phosphorus hydride such as PH3 and P2H4 can be used. In addition, for example, in the case of forming amorphous silicon carbide (a-SiC), in addition to the above-mentioned raw material gas, as a gas for introducing carbon atoms, C and H are constituent atoms, for example, having 1 to 10 carbon atoms. 5 saturated hydrocarbons, C2-C4 ethylene hydrocarbons, C2-C3
The acetylene-based hydrocarbon, etc. can be used. In particular,
Saturated hydrocarbons include methane (CH4), ethane (C2
H6) and other ethylene hydrocarbons include ethylene (C2
H4), propylene (C3H6) and the like include acetylene hydrocarbons such as acetylene (C2H2) and methylacetylene (C3H4). Further, in the case of forming amorphous silicon oxide (a-SiO), for example, oxygen (O2), ozone (O3), monoxide, and monoxide can be used as a gas for introducing oxygen atoms in addition to the above-mentioned raw material gas. Nitrogen (NO), Nitrogen Dioxide (NO2), Nitrogen Dioxide (N2O), Trinitrogen Dioxide (N2O3), Nitrogen Dioxide (N2O4), Nitrogen Dioxide (N2O5), Nitric Oxide (N
O3), silicon atoms (Si), oxygen atoms (O) and hydrogen atoms (H) as constituent atoms, for example, disiloxane (H3SiOSiH3), trisiloxane (H3SiOS)
Examples thereof include lower siloxanes such as iH2OSiH3).

In the present invention, for example, when forming amorphous silicon nitride (a-SiN), nitrogen (N2), ammonia ( NH3), hydrazine (H2NNH2), hydrogen azide (HN3) and other gaseous or gasifiable nitrogen, and nitrogen compounds such as nitrogen compounds and azides. In addition to this, nitrogen trifluoride (F3N), nitrogen tetrafluoride (F4N2) can be supplied in addition to the supply of halogen atoms.
And nitrogen halide compounds such as Similarly, the gas pressure in the reaction vessel is appropriately selected in accordance with the desired characteristics of the deposited film, but in the normal case, it is preferably 0.01 to 1000 Pa, preferably 0.03 to 300 Pa.
Pa, optimally 0.1 to 100 Pa is preferable.

[0026]

EXAMPLES Experimental Examples 1 and Examples of the present invention will be described below, but the present invention is not limited thereto. <Experimental Example 1> The deposited film forming apparatus shown in FIG. 5 is provided with the high-frequency introducing means of the present invention shown in FIG. 1, and the bias of plasma is investigated by measuring a saturated electron current using a single probe (Langmuir probe). It was In this experimental example, the length of the high frequency introducing means was 420 mm. The single probe has a mechanism that can be moved in a vacuum, and the saturated electron current was measured every 20 mm in the busbar direction of the high-frequency introducing means. The discharge conditions at this time are shown in Table 1.

[0027]

[Table 1] The distribution of the saturated electron current thus measured is shown in FIG.
In FIG. 6, the maximum value of the saturated electron current is standardized with the maximum value being 1. As is clear from FIG. 6, no bias in discharge was observed in the high frequency introducing means of the present invention.

<Comparative Experimental Example 1> The conventional high frequency introducing means was installed in the deposited film forming apparatus shown in FIG. 5, and the bias of plasma was measured in exactly the same manner as in Experimental Example 1. In the high-frequency introducing means used in this experimental example, the electrode was a metal of muku, a cover made of ceramic material was provided, and the gap between the electrode and the cover was about 1 mm. However, this value is a value in the device design and does not indicate that the actual gap is constant at about 1 mm.
The other shapes are the same as those used in Experimental Example 1.

The results of the measurements thus obtained are shown in FIG. Figure 7
In the same manner as in the case of Experimental Example 1, the maximum value of the saturated electron current was normalized to 1 and shown. As is clear from the results of FIG. 7, a bias of plasma was observed in the conventional high-frequency introducing means.

<Experimental Example 2> The high-frequency introducing means of the present invention shown in FIG. 1 is installed in the deposited film forming apparatus shown in FIG. 5, and the saturated electron current is measured and the deposited film is measured using a single probe (Langmuir probe). The deposition rate was measured. In this experimental example, the length of the high frequency introducing means is 4
It was set to 20 mm. The single probe has a mechanism that can be moved in a vacuum, and the saturated electron current is measured every 20 mm in the generatrix direction of the high-frequency introducing means. The discharge conditions at this time are shown in Table 2.
Shown in.

[0031]

[Table 2] <Comparative Experimental Example 2> The conventional high-frequency introducing means was installed in the deposited film forming apparatus shown in FIG. 5, and the saturated electron current and the deposition rate of the deposited film were measured in exactly the same manner as in Experimental Example 2. In the high-frequency introducing means used in this experimental example, the electrode was a metal of muku, a cover of ceramic material was provided, and the gap between the electrode and the cover was changed from about 0.2 mm to 20 mm. However, this value is a value in the device design and does not indicate that the actual gap is uniform at each value. The other shapes are the same as those used in Experimental Example 2.

The results of Experimental Example 2 are shown in FIG. 8 for the saturation electron current unevenness and in FIG. 9 for the deposition rate. In FIG. 8, the value of the unevenness of the saturated electron current is shown by the ratio of the smallest value to the largest value (1 when there is no unevenness) for each experiment. Further, in FIG. 9, the deposition rate is set to 1 when the gap is 0.2 mm, and the ratio is shown.

As is clear from the results shown in FIGS. 8 and 9, the conventional high-frequency introducing means having a gap between the electrode and the cover causes the saturation electron current to be uneven. When the size of the gap becomes large, the unevenness tends to be alleviated, but the unevenness was still observed even when the gap was 20 mm. On the other hand, when the gap is increased, the deposition rate decreases and the loss of high frequency power is considered to increase gradually. This tendency was particularly remarkable when the gap was 10 mm or more.

<Experimental Example 3> The high-frequency introducing means of the present invention shown in FIG. 1 is installed in the deposited film forming apparatus shown in FIG.
A charge injection blocking layer 10 on a substrate 1002,
03, a photoconductive layer 1004, and a surface layer 1005 were laminated in this order to prepare an electrophotographic light-receiving member 1001 for electrophotography. The discharge conditions are shown in Table 3 below.

[0035]

[Table 3] The "layer thickness" in Table 3 above is a rough guideline for designing a light receiving member for electrophotography.

In this experimental example, the material of the insulator serving as the base material was alumina ceramics, and the surface roughness (10-point average roughness) on the glow discharge region side was changed from about 1 μm to about 300 μm by the blast method. With respect to the electrophotographic light-receiving member thus prepared, the number of spherical projections was evaluated as follows.

<Evaluation of Spherical Protrusions> The surface of each light-receiving member for electrophotography was observed with an optical microscope, and the number of spherical protrusions having a diameter of 10 μm or more per 10 cm ² was examined. Regarding the number of spherical projections, a value obtained by measuring all eight electrophotographic light-receiving members simultaneously formed and then averaging the whole was adopted.

<Comparative Experimental Example 3> In the deposited film forming apparatus shown in FIG. 5, the conventional RF induction means in which alumina ceramics was plasma sprayed on the electrode surface was used to change the surface roughness from about 1 μm to about 300 μm. A light-receiving member for electrophotography was prepared in the same manner as in 3. The electrophotographic light-receiving member thus prepared was evaluated for the number of spherical projections in the same manner as in Experimental Example 3.

<Comparative Experimental Example 4> In the deposited film forming apparatus shown in FIG. 5, the electrode surface is not provided with an insulator coating (only metal electrode), and a conventional high-frequency introducing means is used to obtain a surface roughness of about 1 μm to about 300 μm. The same procedure as in Experimental Example 3 was performed to prepare a light receiving member for electrophotography. The electrophotographic light-receiving member thus prepared was evaluated for the number of spherical projections in the same manner as in Experimental Example 3.

The results of Experimental Example 3 and Comparative Experimental Examples 3 and 4 are shown in FIG. In FIG. 11, the value of the spherical protrusions was relatively evaluated with the value of the experimental example 3 having a surface roughness of about 30 μm as 1. According to FIG. 11, the film peeling is suppressed and the spherical projections tend to be reduced when the surface of any of the high frequency introduction means is roughened, but the high frequency introduction means of the present invention of Experimental Example 3 has the most spherical projections. It was effective in preventing the occurrence of the particles, and good results were obtained with any surface roughness. However, when the surface roughness exceeds 200 μm, it becomes relatively difficult to obtain a surface roughness higher than 200 μm, so that the surface roughness is preferably 200 μm or less in practical use, and further 5 μm.
To 200 μm is most desirable. On the other hand, in the high-frequency introducing means of Comparative Experimental Example 3 (alumina ceramics plasma-sprayed), the surface of the sprayed body was observed. As a result, traces of partial peeling of the sprayed body were confirmed for all of the surface roughnesses. The degree of peeling tended to worsen as the surface roughness became rougher. Therefore, the result of FIG. 11 shows that the adhesion of the film is improved and the spherical projections are improved by increasing the surface roughness, but the influence of the peeling of the thermal spray material becomes more and more remarkable, and therefore, from a certain roughness. On the contrary, it is considered that the spherical projections tend to increase. Comparative experimental example 4
By increasing the surface roughness with the high frequency introduction means of
It can be seen that the spherical protrusions are reduced but inferior to the high frequency introducing means of the present invention. Example 1 The high-frequency introducing means of the present invention shown in FIG. 1 was installed in the deposited film forming apparatus shown in FIG. 5 to prepare an electrophotographic light-receiving member having the layer structure shown in FIG. The discharge conditions are shown in Table 4.

[0041]

[Table 4] The "layer thickness" in Table 4 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated for the number of spherical projections in the same manner as in Experimental Example 3, and for the film thickness unevenness and the image density unevenness according to the following methods.

<Evaluation of Thickness Unevenness> The film thickness was measured using an eddy current type film thickness meter at a total of 17 points at 2 cm intervals in the generatrix direction of each electrophotographic light-receiving member. The values measured in this way were simultaneously prepared for each measurement point.
Taking the average value among the electrophotographic light-receiving members of the book, the ratio of the minimum film thickness to the maximum film thickness of the electrophotographic light-receiving member in the bus line direction is calculated, and the unevenness in the bus line direction is calculated. As compared.

<Evaluation of Image Density Unevenness> Each of the photoreceptive members for electrophotography was replaced with an electrophotographic apparatus (NP6060 manufactured by Canon Inc.).
The original halftone chart (part number: FY9-9042) manufactured by Canon Inc. on the platen, and the image density at any 50 points on the copy image obtained when copying. Is measured with a reflection densitometer, and for each electrophotographic light-receiving member, the ratio of the portion with the lowest image density to the portion with the highest image density is calculated, and all eight light-receiving members for electrophotography prepared at the same time are calculated. The above measurement was performed, and finally the average value of the ratios was compared as image density unevenness.

<Comparative Example 1> The conventional high-frequency introducing means in which the electrodes are covered with an alumina ceramics cover is installed in the deposited film forming apparatus shown in FIG. A light-receiving member for electrophotography was prepared under the conditions, and in the same manner as in Example 1, three items, that is, the number of spherical projections, film thickness unevenness, and image density unevenness were evaluated. In this comparative example, the gap between the electrode and the alumina ceramic cover was about 0.5 mm. It should be noted that this gap is a value in the device design, and does not indicate that the actual gap is uniform at 0.5 mm.

<Comparative Example 2> In the deposited film forming apparatus shown in FIG. 5, a conventional high-frequency introducing means in which the surface of the electrode was coated with alumina ceramics by plasma spraying was installed. A light receiving member for electrophotography was prepared under the conditions shown, and in the same manner as in Example 1, three items of spherical projections, film thickness unevenness, and image density unevenness were evaluated.

The results of Example 1 and Comparative Examples 1 and 2 are shown in Table 5.

[0047]

[Table 5] In Table 5, each item is shown by relative evaluation with the value of Example 1 being 1. As is clear from Table 5, in the high frequency introducing means of Comparative Example 1, the film thickness unevenness and the image density unevenness are worse than those of the high frequency introducing means of the present invention (Example 1).
In Comparative Example 2, the number of spherical protrusions is slightly worse than that in Example 1. Good results were obtained in all the items of the electrophotographic light-receiving member of Example 1.

[Embodiment 2] The high frequency introducing means of the present invention shown in FIG. 1 is installed in the deposited film forming apparatus shown in FIG. 5, and the frequency of high frequency power is 20 MHz, 50 MHz, 105 M.
10 Hz, 200 MHz, 450 MHz, and FIG.
An electrophotographic light-receiving member having the layer structure shown in 1 was prepared. Table 6 shows the discharge conditions.

[0049]

[Table 6] The "layer thickness" in Table 6 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated in the same manner as in Example 1 with respect to the number of spherical projections, film thickness unevenness, and image density unevenness.

The results are shown in Table 7.

[0051]

[Table 7] In Table 7, each item is shown by relative evaluation with 1 when the frequency of the high frequency power is 105 MHz.
As is clear from Table 7, an electrophotographic light-receiving member having good characteristics in both spherical projections and unevenness was obtained at any frequency.

[Embodiment 3] The high-frequency introducing means of the present invention in which the internal cavity shown in FIG. 2 is filled with metal is installed in the deposited film forming apparatus shown in FIG.
MHz, 50 MHz, 105 MHz, 200 MHz, 4
By changing the frequency to 50 MHz, an electrophotographic light-receiving member having the layer structure shown in FIG. 10 was prepared. Table 8 shows the discharge conditions.

[0053]

[Table 8] The "layer thickness" in Table 8 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated in the same manner as in Example 1 with respect to the number of spherical projections, film thickness unevenness, and image density unevenness.

The results are shown in Table 9.

[0055]

[Table 9] In Table 9 above, each item is shown by relative evaluation with 1 when the frequency of the high frequency power of Example 2 was 105 MHz. As is clear from Table 9, an electrophotographic light-receiving member having good characteristics in both spherical projections and unevenness was obtained at any frequency.

[Embodiment 4] The high frequency introducing means of the present invention provided with the cooling mechanism shown in FIG. 3 is installed in the deposited film forming apparatus shown in FIG. 5, and the frequency of high frequency power is 20 MHz, 50.
MHz, 105 MHz, 200 MHz, and 450 MHz were changed to prepare an electrophotographic light-receiving member having the layer structure shown in FIG. Table 10 shows the discharge conditions.

[0057]

[Table 10] The "layer thickness" in Table 10 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated in the same manner as in Example 1 with respect to the number of spherical projections, film thickness unevenness, and image density unevenness.

The results are shown in Table 11.

[0059]

[Table 11] In Table 11 above, each item is shown by relative evaluation with 1 when the frequency of the high frequency power of Example 2 was 105 MHz. As is clear from Table 11, an electrophotographic light-receiving member having good characteristics in both spherical projections and unevenness was obtained at any frequency.

[Embodiment 5] The high-frequency introducing means of the present invention having a heating mechanism is installed in the deposited film forming apparatus shown in FIG.
The frequency of high frequency power is 20MHz, 50MHz, 10
By changing the frequency to 5 MHz, 200 MHz, and 450 MHz, an electrophotographic light-receiving member having the layer structure shown in FIG. 10 was prepared. Table 12 shows the discharge conditions.

[0061]

[Table 12] The "layer thickness" in Table 12 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated in the same manner as in Example 1 with respect to the number of spherical projections, film thickness unevenness, and image density unevenness.

The results are shown in Table 13.

[0063]

[Table 13] In Table 13 above, each item is shown by relative evaluation with 1 when the frequency of the high frequency power of Example 2 was 105 MHz. As is clear from Table 13, an electrophotographic light-receiving member having good characteristics in both spherical projections and unevenness was obtained at any frequency.

[Embodiment 6] The high frequency introducing means of the present invention, which also serves as the source gas supplying means shown in FIG. 4, is installed in the deposited film forming apparatus shown in FIG.
Hz, 50MHz, 105MHz, 200MHz, 45
By changing the frequency to 0 MHz, a light-receiving member for electrophotography having the layer structure shown in FIG. 10 was prepared. Table 14 shows the discharge conditions.

[0065]

[Table 14] The "layer thickness" in Table 14 above is an approximate guide for designing the electrophotographic light-receiving member. The electrophotographic light-receiving member thus prepared was evaluated in the same manner as in Example 1 with respect to the number of spherical projections, film thickness unevenness, and image density unevenness.

The results are shown in Table 15.

[0067]

[Table 15] In Table 15 above, each item is shown by relative evaluation with 1 when the frequency of the high frequency power of Example 2 was 105 MHz. As is clear from Table 11, an electrophotographic light-receiving member having good characteristics in both spherical projections and unevenness was obtained at any frequency.

[0068]

According to the present invention, with the above construction, it is possible to prevent the film peeling from the surface of the high frequency introducing means and the localization of plasma, which is a problem in producing the light receiving member for electrophotography. It is possible to effectively suppress the occurrence of spherical protrusions, film thickness unevenness, and image density unevenness, and to form an electrophotographic light-receiving member having extremely excellent image characteristics.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of high-frequency introducing means of a deposited film forming apparatus of the present invention.

FIG. 2 is a schematic view showing an example of high-frequency introducing means of the deposited film forming apparatus of the present invention.

FIG. 3 is a schematic view showing an example of a high frequency introducing unit of the deposited film forming apparatus of the present invention.

FIG. 4 is a schematic view showing an example of high-frequency introducing means of the deposited film forming apparatus of the present invention.

FIG. 5 is a schematic view showing an example of a deposited film forming apparatus of the present invention.

FIG. 6 is a graph showing a distribution of a saturated electron current in the deposited film forming apparatus of the present invention in Experimental Example 1.

FIG. 7 is a graph showing a distribution of a saturated electron current in the conventional deposited film forming apparatus in Comparative Experimental Example 1.

FIG. 8 is a graph showing distributions of saturated electron currents in Experimental Example 2 and Comparative Experimental Example 2.

9 is a graph showing a deposition rate in Experimental Example 2 and Comparative Experimental Example 2. FIG.

FIG. 10 is a schematic cross-sectional view showing the layer structure of a light-receiving member for electrophotography prepared in each example and the like.

11 is a graph showing the number of spherical protrusions in Experimental Example 3 and Comparative Experimental Examples 3 and 4. FIG.

[Explanation of symbols]

100: reaction vessel 101: Base 102: High frequency introducing means 103: glow discharge region 104: heater for heating the substrate 105: means for introducing raw material gas 106: High frequency matching box 107: power supply 108: rotating shaft l09: Motor 110: Gear 111: Insulator 112: Electrode 113: Cavity 114: Gap 115: Metal rod 116: Raw material gas release hole 117: Raw material gas inlet 118: Flow path for raw material gas 119: Refrigerant supply port 120: Refrigerant introduction pipe 121: Refrigerant outlet 1001: Photoreceptive member for electrophotography 1002: base 1003: Charge injection blocking layer 1004: Photoconductive layer 1005: surface layer

Front page continued (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/205 C23C 16/50 G03G 5/08 105 G03G 5/08 360 H01L 21/31

Claims (10)

(57) [Claims] 1. A plurality of cylindrical conductive bases are rotatably arranged on the same circumference in a vacuum-tight reaction vessel, and a source gas introducing means is arranged in the circumference of the cylindrical conductive bases. In the deposited film forming apparatus, which introduces the raw material gas through the high frequency power means, introduces the high frequency power through the high frequency power means, causes the glow discharge by the high frequency power, and forms the deposited film on the cylindrical conductive substrate. High frequency power introduction means
An insulating material is used as a base material, and a metal material having a thickness sufficient to transmit the high frequency power is formed in close contact with the insulating material in a region separated from the glow discharge region by the insulating material. A deposited film forming apparatus characterized by the following. 2. The deposited film forming apparatus according to claim 1, wherein the insulating base material is a ceramic material. 3. The deposited film forming apparatus according to claim 1 or 2, wherein the high frequency introducing means includes a cooling mechanism. 4. The deposited film forming apparatus according to claim 1, wherein the high-frequency introducing means includes a heating mechanism. 5. The deposited film forming apparatus according to claim 1, wherein the high frequency introducing means also serves as a raw material gas introducing means. 6. The roughness of the surface of at least the portion of the insulating base material which is in contact with glow discharge is in the range of 5 μm to 200 μm in terms of ten-point average roughness with a reference length of 2.5 cm. The deposited film forming apparatus according to any one of claims 1 to 5. 7. A plurality of cylindrical conductive bases are rotatably arranged on the same circumference in a vacuum-tight reaction container, and a raw material gas and high-frequency power are placed in the circumference of the cylindrical conductive bases. In the method of forming a deposited film in which a glow discharge is generated by the high-frequency power to form a deposited film on the cylindrical conductive substrate, the high-frequency power is introduced by using an insulating material as a base material. A metal material having a sufficient thickness for transmitting the high frequency power is introduced into the region separated from the glow discharge region by the material by high frequency power introducing means formed by closely contacting with the insulating material to form a deposited film. A method for forming a deposited film, comprising: 8. The high frequency power has a frequency of 20 MHz to
The deposition film forming method according to claim 7, wherein the deposition frequency is in the range of 450 MHz. 9. The method for forming a deposited film according to claim 7, wherein the high-frequency introducing means is cooled. 10. The deposited film forming method according to claim 7, wherein the high-frequency introducing means is heated.