JP3406936B2 - Plasma CVD method using ultrashort wave and plasma CVD apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD method using ultrashort waves capable of forming a large-area deposited film having a uniform thickness and a uniform film thickness at a high deposition rate, and a plasma suitable for carrying out the plasma CVD method. The present invention relates to a CVD device. More specifically, the present invention is directed to devices having large areas, such as electrophotographic photoreceptors, at relatively high deposition rates using frequencies in the region higher than those used in conventional RF plasma CVD processes. The present invention relates to a plasma CVD method capable of forming a large-area deposited film with a uniform film thickness and a uniform film quality, and a plasma CVD apparatus suitable for carrying out the plasma CVD method.

[0002]

2. Description of the Related Art In recent years, a so-called RF plasma CVD method has been widely used in the manufacture of semiconductor devices.
In the RF plasma CVD method, 13.56 MH
The high frequency of z is generally used from the viewpoint based on the Radio Law. The RF plasma CVD method has the advantages that the discharge conditions are relatively easy to control and the quality of the obtained film is excellent, but the gas utilization efficiency is low and the deposition film formation rate is relatively low. There is. In order to solve this problem, a microwave CVD method using a so-called microwave having a frequency of 2.45 GHz has been proposed. The microwave CVD method has an advantage that the gas utilization efficiency is high and the deposition rate of the deposited film can be remarkably increased, but the plasma density at the time of film formation is extremely high, which causes rapid decomposition of the source gas. Since film deposition is performed at high speed, it is extremely difficult to stably form a dense deposited film.

Against this background, recently 13.56 MHz
Studies have been made on a plasma CVD method using a so-called VHF region in the so-called VHF region having a higher frequency of about 30 MHz to 150 MHz. For example, Plasma Ch
emissary and Plasma Procedures
sing, Vol 7, No3, (1987) p267
-273 (hereinafter referred to as "Reference 1") uses a capacitively coupled glow discharge decomposer to decompose a raw material gas (silane gas) with ultrashort wave energy having a frequency of 25 to 150 MHz and amorphous silicon (a). -Si) film formation is described. Specifically, in Document 1, the frequency is changed in the range of 20 MHz to 150 MHz, and
-When a Si film is formed and 70 MHz is used, the film deposition rate becomes the highest at 21 Å / sec, which is about 5 to 8 times the formation rate in the case of the above-mentioned RF plasma CVD method, and Defect density of the obtained a-Si film,
It is stated that the optical bandgap and conductivity are not significantly affected by the excitation frequency. However, the film formation described in Reference 1 is of a laboratory scale, and there is no mention of whether such effects can be expected in the formation of a large-area film. Incidentally, in Reference 1, the use of high frequency (13.56 MHz to 200 MHz) is several μm.
It merely suggests the possibility as it opens an interesting perspective on high-speed processing of low-cost large-area a-Si: H thin-film devices, which require a large thickness. As will be apparent from the results of experiments conducted by the present inventors, which will be described later, this point, although the use of so-called VHF energy in the VHF region brings about high gas decomposition efficiency and high deposition rate,
It is difficult to form a large-area deposited film that can be put to practical use. In addition, Japanese Patent Laid-Open No. 3-64466 (hereinafter referred to as "reference 2") discloses that the frequency is 20 MHz or higher (preferably 30 M).
It discloses a method of forming an amorphous silicon based semiconductor film on a cylindrical substrate by using ultra high frequency energy of (Hz to 50 MHz). Specifically, a raw material gas is introduced into the reaction chamber, the reaction chamber is set to a gas pressure of 10 ^{−4 to} 0.2 Torr, and the flow rate of the raw material gas is set to 0.1.
Disclosed is a method of forming an amorphous silicon-based semiconductor film by introducing a microwave energy of an amount corresponding to -10 w / sccm into the reaction chamber to generate a glow discharge. According to the method of Reference 2, the film forming rate is 10 μm / ho
ur or more, and the unevenness of the thickness of the obtained deposited film is reduced to 20
It is said that it can be reduced to less than%.

[0004]

[Patent Document 2]
In the above method, even if an attempt is made to achieve the above-mentioned film deposition rate using ultra-short wave energy having a frequency exceeding the above-mentioned frequency range, a satisfactory result cannot be obtained. That is, as will be described later, the present inventors tried the method described in Document 2 using a high frequency power source having a frequency of 40 MHz or more. When the frequency was 60 MHz or more, the axial direction and the circumferential direction of the cylindrical substrate were It was found that the film thickness of the deposited film was uneven for each of them, and a good quality film could not be obtained at a high deposition rate.

The main object of the present invention is to solve the above-mentioned problems in the prior art, and to make the film thickness on the surface of the cylindrical substrate extremely in both the axial direction and the circumferential direction of the cylindrical substrate. A plasma CVD method (hereinafter referred to as "VHF plasma CVD") using a high frequency in the VHF region capable of forming a high-quality deposited film having a uniform and uniform film quality at a high speed.
Law ”).

A further object of the present invention is to provide a VHF plasma CVD method capable of preventing the loss of high frequency power due to an increase in the frequency of the high frequency power source and efficiently generating plasma.

Another object of the present invention is that the cathode electrode provided around the cylindrical base body is electrically divided into a plurality of portions in the axial direction of the cylindrical base body, and the divided cathodes are separated.
Provided is a VHF plasma CVD method in which ultra-high frequency energy in a frequency range of 60 MHz to 300 MHz is supplied to each of the electrode electrodes through a high frequency power supply means to generate plasma in a reaction vessel and form a deposited film on a cylindrical substrate. To do.

Still another object of the present invention is that a cathode electrode surrounding a cylindrical substrate is electrically divided into a plurality of portions in the axial direction of the cylindrical substrate, and each of the divided cathode electrodes is separated. Frequency of 60 MH via high frequency power supply means
Another object of the present invention is to provide a plasma CVD apparatus adapted to supply ultrashort wave energy in the range of z to 300 MHz.

[0009]

The VHF plasma CVD method of the present invention which achieves the above object includes the following two aspects. That is, the first aspect of the present invention is to supply a raw material gas for forming a deposited film into a reaction vessel under reduced pressure and to provide a cathode provided around a rotatable cylindrical substrate arranged in the reaction vessel. High frequency power generated by a VHF band high frequency power source is supplied to the cathode electrode through a high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form a surface of the cylindrical substrate. deposited film a VHF plasma CVD method for forming the a, the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, split by said cathode - cathode electrode Frequency of 60 MHz to 300 M via the high-frequency power supply means.
Ultrashort wave energy in the range of Hz is supplied to generate plasma in the reaction vessel to form a deposited film on the cylindrical substrate.

In a second aspect of the present invention, a raw material gas for forming a deposited film is supplied into a reaction vessel under reduced pressure and is provided around a rotatable cylindrical substrate arranged in the reaction vessel. The high frequency power generated by the VHF band high frequency power supply is supplied to the cathode electrode through the high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form the surface of the cylindrical substrate. a VHF plasma CVD method for forming a deposited film on the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, split by said cathode - de Each of the electrodes has a plurality of connection points independently connected to the high frequency power supply means, and the frequency is 60 MHz to 300 M via the plurality of connection points.
Ultrashort wave energy in the range of Hz is supplied to generate plasma in the reaction vessel to form a deposited film on the cylindrical substrate.

The present invention includes a plasma CVD apparatus suitable for carrying out the above plasma CVD method. That is, the plasma CVD apparatus of the present invention includes the following two modes. That is, the first apparatus mode includes a reaction vessel capable of depressurizing, a raw material gas supply means for supplying a raw material gas for forming a deposited film into the reaction vessel, a rotatable substrate holding means arranged in the reaction vessel, A cathode electrode and a VHF band high frequency power source are provided so as to surround a cylindrical substrate disposed in the substrate holding means, and the high frequency power generated by the VHF band high frequency power source is supplied via the high frequency power supply means. A plasma CVD apparatus for supplying a plasma to the cathode electrode to generate plasma between the cylindrical substrate and the cathode electrode to form a deposited film on the surface of the cylindrical substrate. cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, each being divided cathode - frequency through the radio-frequency power supply means to each of the cathode electrode 60MHz
It is characterized in that ultrashort wave energy in the range of up to 300 MHz is supplied.

A second apparatus mode is a reaction vessel capable of reducing pressure,
A raw material gas supply means for supplying a raw material gas for forming a deposited film into the reaction vessel, a substrate holding means arranged in the reaction vessel, and a cylindrical substrate arranged in the substrate holding means are provided so as to surround the substrate. And a cathode electrode and a VHF band high frequency power source, and the high frequency power generated by the VHF band high frequency power source is supplied to the cathode electrode through a high frequency power supply means to supply the cylindrical substrate and the cathode. A plasma CVD apparatus for forming a deposited film on the surface of the cylindrical substrate by generating plasma between the cathode electrode and the cathode electrode, wherein the cathode electrode is electrically connected in the axial direction of one of the cylindrical substrates. is divided into a plurality, each has been split cathode - each cathode electrode is independently a plurality of connection points for electrically connecting to the high-frequency power supply means, frequency 60 via a plurality of connection points
It is characterized in that ultrashort wave energy in the range of MHz to 300 MHz is supplied to each cathode electrode.

According to the present invention, a high-quality deposited film having extremely uniform film thickness and film quality can be formed on the surface of a cylindrical substrate in both the axial direction and the circumferential direction of the cylindrical substrate. It can be stably formed at the deposition rate. Generally, when the frequency of the high frequency power used for film formation is increased, the loss of the high frequency energy increases with the increase, but the present invention is concerned with the use of very high frequency energy in a very large frequency range. However, such energy loss is extremely small and the source gas is efficiently decomposed to generate a desired plasma, so that a desired deposited film can be formed at a high speed.

The present inventors have found that the conventional VHF plasma CV
The experiments described below were conducted in order to solve the above-mentioned problems in the D technique and achieve the above-mentioned object of the present invention. The present invention is
It was completed based on the below-mentioned findings obtained through the experiment.

(Experiment-1) The above-mentioned document 2 (Japanese Patent Laid-Open No. 3-
An experiment was conducted based on the technique described in Japanese Patent No. 64466). That is, electrophotographic photoreceptors having a plurality of amorphous silicon films as photosensitive layers were produced by using high frequency power sources of various frequencies. The influence of the frequency of the high frequency power source on the unevenness of the thickness of the deposited film and the film formation rate was observed in the production of each electrophotographic photosensitive member. Further, the characteristics of the obtained electrophotographic photosensitive member were observed. Each electrophotographic photosensitive member was manufactured by sharing the plasma CVD apparatus shown in FIG. In FIG. 1, 100 is a reaction container. The reaction container 100 includes a base plate 101 and the base plate 101.
A cylindrical insulating member 102A, a cylindrical (inner diameter 208 mm, length 400 mm) cathode electrode 103, and a cylindrical insulating member 102B are arranged on the boot 101. 11
Reference numeral 5 is an upper lid of the reaction container 100. 105A is a base holder, and the base holder is internally provided with a heater support 10.
It has 5A '. 105A "is a heater support 10
5A 'is a heater for heating the substrate. 10
Reference numeral 6 is a cylindrical substrate arranged on the substrate holder 105A. 105B is an auxiliary holding member for the cylindrical substrate 106. The base body holder 105A is provided with a rotating mechanism (not shown) connected to the motor therein so that it can rotate as necessary. Reference numeral 107 denotes an exhaust pipe having an exhaust valve, and the exhaust pipe communicates with an exhaust mechanism 107 'having a vacuum pump. 108
Is a source gas supply system including a gas cylinder, a mass flow controller, a valve, and the like. Raw material gas supply system 1
08 is connected to a gas discharge pipe 116 having a plurality of gas discharge holes via a gas supply pipe 117. The raw material gas is supplied into the reaction vessel through a plurality of gas emission holes of the gas emission pipe 116. 111 is a high frequency power supply. The high frequency power from the high frequency power supply 111 is passed through the high frequency power supply line 118 and the matching circuit 109 to the cathode electrode 1.
03. 104 is a shield wall.

In this experiment, the diameter is 108 mm and the length is 358.
18 cylindrical bases made of Al having a thickness of 5 mm and a thickness of 5 mm were prepared. Using the plasma CVD apparatus shown in FIG. 1, a charge injection blocking layer, a photoconductive layer and a surface protective layer are formed in this order on each Al substrate under the conditions shown in Tables 1 and 2. An electrophotographic photoreceptor was produced. Eighteen electrophotographic photoconductors (Sample No. 1a, 2a, 2b, 3
a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7
a, 7b, 8a, 8b, 9a, 9b and 10a) were produced. Among these electrophotographic photoconductor samples, those marked with "a" are those obtained by rotating the cylindrical substrate during film formation, and those marked with "b" are those that are cylindrical during film formation. The substrate was not rotated. Cylindrical substrate 106 made of Al
On the substrate holder 105A, the reaction container 10
The inside of 0 is evacuated by operating the exhaust mechanism 107 ',
The pressure inside 00 was adjusted to 1 × 10 ⁻⁶ Torr. Then, the heater 105 "is energized to move the cylindrical substrate 106 to 2
It was kept heated at a temperature of 50 ° C. Then, the charge injection blocking layer was formed under the conditions shown in the column of the charge injection blocking layer in Table 1. That is, the SiH ₄ gas is supplied from the source gas supply means 108 via the gas supply pipe 117 and the gas release pipe 116.
Gas, H ₂ gas, NO gas, B ₂ H ₆ gas,
500 sccm, 10 sccm, 10 sccm, 200
It was introduced into the reaction vessel at a flow rate of 0 ppm, and the pressure in the reaction vessel was adjusted to 50 mTorr or 500 mTorr. At such a place, the high frequency power supply 111 generated a high frequency having a frequency of 13.56 MHz to 350 MHz shown in Table 2, and supplied the high frequency to the cathode electrode 103 through the high frequency power supply line 118 and the matching circuit 109. Here, as the high frequency power supply 111, a predetermined high frequency power supply is used so that the frequency in the above range is given. The matching circuit 109 is appropriately adjusted according to the frequency of the high frequency power source. Thus, the cylindrical substrate 106 and the cathode electrode 1
In the space surrounded by 03, the source gas is excited by high-frequency energy and decomposed, and an amorphous silicon film (a) as a charge injection blocking layer is formed on the cylindrical substrate 106.
-Si: H: N: O: B film) was formed with a thickness of about 1 μm. Then, a photoconductive layer made of an a-Si: H film having a thickness of about 25 μm was formed under the conditions shown in the column of photoconductive layer of Table 1 by the same method, and subsequently shown in the column of surface protective layer of Table 1. Under the conditions, a surface protective layer made of an a-SiC: H film having a thickness of about 1 μm was formed, and an electrophotographic photosensitive member was produced. As shown in Table 2, the above film forming operation was repeated by changing the frequency and the internal pressure of the reaction container at the time of film forming corresponding to each electrophotographic photosensitive member sample. Further, in the production of the sample with the reference numeral "a", the rotating mechanism was operated to rotate the cylindrical substrate. In the production of the sample with the reference numeral "b", the cylindrical substrate was not rotated.

Samples 2a, 2b, 3a, 3b, 4
a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8
Two samples were prepared for each of a, 8b, 9a, and 9b. One of these samples was used to evaluate the film thickness distribution, and the other sample was used to evaluate the electrophotographic characteristics.

Sample 1 using a frequency of 13.56 MHz
In the film formation of a, discharge was intermittently generated at the film formation pressure of 50 mTorr, and film formation could not be performed. Therefore, in the case of Samples 2a and 2b, the film formation pressure was 500 m.
A film was formed as Torr. The samples 2a, 2b to 9a, 9b were formed under the conditions shown in Table 1. In the film formation of the sample 10a, discharge was intermittently generated as in the case of the sample 1a, and the film formation could not be performed. For each of Samples 2a and 2b to Samples 9a and 9b, a line is drawn every 33 mm in the axial direction of the base 106, and a line is drawn in the circumferential direction of
The film thickness was measured using an eddy current film thickness meter (manufactured by Kett Scientific Research Institute) at 100 intersections when a line was drawn every 2 mm, and the distribution state of the film thickness was evaluated. Here, the distribution state of the film thickness was evaluated as follows. That is, for the film thickness distribution in the axial direction, the difference between the maximum value and the minimum value of the film thickness at ten measurement points in one row in the axial direction is obtained, and the difference is divided by the average film thickness value at ten points to obtain one row. A film thickness distribution {(maximum value-minimum value) / average value} was determined. Then, similarly for the other 9 rows, the film thickness distribution per row is similarly obtained, and the average value of the obtained film thickness distributions in the 10 rows is calculated, and this is calculated as the axial film thickness distribution (that is, film thickness unevenness) It is shown in Table 3 as a percentage. Regarding the film thickness distribution in the circumferential direction, the difference between the maximum value and the minimum value of the film thickness at 10 measurement points in one row in the circumferential direction is obtained, and the difference is divided by the average film thickness value at 10 points, and The film thickness distribution {(maximum value-minimum value) / average value} was determined.
Then, for the other 9 rows, the film thickness distribution per row was similarly obtained. The average of the film thickness distributions of the 10 rows obtained was shown in the circumferential direction (that is, the film thickness was expressed as a percentage. The film forming speed was calculated for the film thickness distribution values exceeding 20%. When the value of the film thickness distribution (film thickness unevenness) is 20% or less, it is calculated based on the film thickness at 100 locations, and the average value of the obtained values is used as the film forming rate in Table 3 below. Furthermore, samples 2a and 2b to sample 9 are shown in FIG.
For samples a and 9b, these samples were mounted on an electrophotographic copying machine (NP6060 manufactured by Canon Inc., which was modified for experiments), and the chargeability and the images obtained were evaluated. The results obtained are shown in Table 3. The evaluation of each evaluation item at this time was performed based on the following criteria.

Evaluation of charging ability : The sample was mounted on an electrophotographic copying machine, a voltage of +6 KV was applied to the charger to carry out corona charging, and the surface potential of the dark portion of the sample was measured by a surface potential meter. The measurement at this time is carried out at a total of 100 points in the same manner as in the case of the evaluation of the above-mentioned film thickness distribution, the average value is obtained from the obtained measurement results, and the value farthest from the average value is calculated according to the following criteria. evaluated. ⊚: 10 V or less, which is extremely excellent uniformity. : 20V or less, which is good uniformity. (Triangle | delta): It is 30V or less, and there is no problem practically. X: The voltage exceeds 30 V, which is inferior in uniformity and is insufficient when used in a high-speed copying machine.

Image Evaluation : Full-faced halftone original (Halftone test chart FY9-90 manufactured by Canon Inc.)
42) was placed on a document table, an image was formed to obtain an image sample, and the obtained image was evaluated according to the following evaluation criteria. A: An excellent image with no density unevenness. : A good image with slight density unevenness. B: The image is worth the use although there is unevenness in density as a whole. X: An image in which density unevenness is remarkable and is not suitable for use.

From the above experiment, the following facts were found.
That is, (i) when the substrate is rotated to form a film, the film thickness unevenness in the axial direction increases depending on the frequency when the power supply frequency is increased above 40 MHz, but the film thickness unevenness in the circumferential direction increases. (Ii) When film formation is performed without rotating the substrate, both film thickness unevenness in the axial direction and film thickness unevenness in the circumferential direction are dependent on the frequency when the power supply frequency is set to be greater than 40 MHz. (Iii) The power supply frequency is 40M regardless of whether the substrate is rotated or not.
When the frequency exceeds Hz, the image characteristics of the obtained electrophotographic photoreceptor deteriorate.

(Experiment-2) In consideration of the results obtained in Experiment-1, the frequency of the high frequency power to be used is 40 MHz in this experiment.
Even when it is set to be larger than z, the deposited film to be formed does not have thickness unevenness, and the electrophotographic photosensitive member made of the deposited film can be satisfactory in charging ability and copied image. This was done from the viewpoint of determining sex. In this experiment, in the plasma CVD apparatus used in Experiment-1, a plurality of high frequency power supply lines for supplying high frequency power to the cathode electrode and the cathode electrode are provided in contact, and the cathode electrode is connected to the contacts. Film formation was performed using a plasma CVD apparatus that was changed so that electric power was supplied. The plasma CVD apparatus used in this experiment has the configuration shown in FIG. The plasma CVD apparatus shown in FIG. 2 has a high frequency power supply line 11 for supplying the high frequency power generated by the high frequency power supply 118 to the cathode electrode 103.
8 is 11 on the cathode electrode 103 side with respect to the matching circuit 109.
8A and 118a are branched into two parts, a contact point between 118A and the cathode electrode 103, and 118a and the cathode electrode 1
Plasma CV shown in FIG. 1 except that power is supplied to the cathode electrode 103 from two points of contact with 03.
It has the same configuration as the D device. Description of the same components as those of the plasma CVD apparatus of FIG. 1 will be omitted. The contact point between the high-frequency power supply line 118A and the cathode electrode 103 and the contact point between the high-frequency power supply line 118a and the cathode electrode 103 were provided at symmetrical positions with respect to the cylindrical substrate 106. In this experiment, Sample 2 prepared in Experiment-1
Samples 12a, 12b to 19a and 19b were prepared under the same conditions as those for samples a, 2b to 9a and 9b.
Then, these samples were evaluated in the same manner as Experiment-1. The results obtained are shown in Table 4.

The following facts were found from the results shown in Table 4.

That is, (i) by supplying the electric power to the cathode electrode from a plurality of points, the unevenness of the film thickness in the circumferential direction of the substrate can be suppressed to a low level; (ii) the electric power supply to the cathode electrode By carrying out from a plurality of connection points, the film thickness unevenness in the axial direction is slightly suppressed as compared with the case where power is supplied from one point (Table 3), but regardless of whether or not the substrate is rotated, When the power supply frequency exceeds 40 MHz, the film thickness unevenness in the axial direction increases depending on the power supply frequency; (iii) regardless of whether or not the substrate is rotated, the image of the electrophotographic photosensitive member manufactured at a power supply frequency of 100 MHz or more. The characteristics are not sufficient.

(Experiment-3) The above-mentioned Experiment-1 and Experiment-
In view of the result of No. 2, the reason why the unevenness of the film thickness in the axial direction of the cylindrical substrate becomes large when a high frequency power source with a frequency exceeding 40 MHz is used was examined in this experiment. The present inventors presumed as follows about the cause of the increase in the film thickness unevenness in the axial direction of the cylindrical substrate in the plasma CVD apparatus used in each of Experiment-1 and Experiment-2. That is, since the high-frequency power supplied from the high-frequency power supply to the cathode electrode is so-called skin effect and is supplied through the thin portion from the surface of the cathode electrode, it is supplied only through the portion near the cathode electrode. The deep part from the surface of the cathode electrode does not pass. Then, as the frequency of the high frequency power source increases, the skin effect becomes remarkable, and the high frequency power passes only through the extremely thin portion that is very close to the electrode surface. in this case,
The resistance of the cathode electrode increases, and it becomes more difficult for high frequency power to be transmitted. This is well known in the art. Plasma CV used in Experiment-1 and Experiment-2
In the D device, electric power is supplied from the outer peripheral portion of the cylindrical cathode electrode 103 to which the high frequency power supply line 118 is connected to the inner peripheral portion of the surface of the electrode. When the supplied high frequency power has a high frequency, the cylindrical cathode electrode 10 faces the cylindrical substrate 106.
Before reaching the central portion of the inner circumference of 3, the electric power is applied to the cylindrical substrate 1
It is used as discharge generation energy near the upper end or lower end of 06. Therefore, it is considered that a difference occurs in the plasma density between the both ends and the center of the cylindrical substrate, and the difference in the plasma density causes the axial film thickness unevenness. Therefore, in this experiment, in the plasma CVD of FIG.
Using the plasma CVD apparatus shown in FIG. 3 in which the probe 130 for measuring plasma density is arranged in the apparatus, the cylindrical substrate 1
The plasma density of the discharge space surrounded by 06 and the cylindrical cathode electrode 103 was measured at various positions. In FIG. 3, 131 is a seal flange. 130 is professional
It is designed to be movable up and down. The plasma density (electron density N _e ) was calculated by the following equation, using the single probe method to obtain the thermal diffusion electron current I _e0 and the electron temperature T _e . S in the following formula represents the surface area of the probe.

N _e = 3.73 × 10 ¹¹ × I _e0 ÷ S ÷ T _e ^{1/2 In} this experiment, frequencies of 40 MHz and 100 MHz are used.
The influence of the frequency on the plasma density was examined by using the high frequency power supply of. Specifically, in Experiment-1, the sample 3a (frequency 40 MHz) and the sample 5a (frequency 100) were used.
MHz) and the photoconductive layer shown in Table 1 was formed under the same conditions as above. During the formation of the photoconductive layer, the probe 130 was moved up and down to move the cylindrical substrate 106 and the cathode electrode 103.
The plasma density of the discharge space surrounded by was measured. Professional
The relationship between the position of the bulge and the plasma density is plotted in FIGS. 4 and 5. In FIGS. 4 and 5, the position of 1/2 height of the cylindrical substrate 106 having a height of 358 mm is set to zero with reference to the substrate holder-105A, and the upper side and the lower side are set to plus and minus. . As is clear from FIG. 4, when a high frequency power source with a frequency of 40 MHz is used, a relatively uniform plasma density is obtained over a range of 358 mm or more where the cylindrical substrate 106 is arranged. On the other hand, as is apparent from FIG. 5, when a high frequency power source with a frequency of 100 MHz is used, there is a considerable difference in plasma density within the range of 358 mm where the cylindrical substrate 106 is arranged. It can be seen that the plasma density is smallest near the position where the height of the substrate 106 is 1/2 (that is, the position of zero), and the plasma density increases toward the end of the substrate. The film thickness distributions of the silicon film on the cylindrical substrate 106 formed by using the high frequency power of 40 MHz and the silicon film on the cylindrical substrate formed by using the high frequency power of 100 MHz are shown. When the same method as in Experiment-1 was examined, it was found that the former silicon film had a relatively uniform film thickness distribution depending on the plasma density distribution shown in FIG. Further, it was found that the latter silicon film had a non-uniform film thickness distribution depending on the plasma density distribution shown in the fifth.

(Experiment-4) In consideration of the result of Experiment-3, the effect of the skin effect is small in this experiment, and there is a variation in the plasma density in the discharge space surrounded by the cylindrical substrate 106 and the cylindrical cathode electrode 103. A small plasma CVD apparatus was separately used for the study. In this experiment, a cathode electrode was electrically divided into a plurality of parts in the axial direction of a cylindrical substrate, and a plasma CVD device capable of supplying high-frequency power to each of the divided cathode electrodes was produced and used. And cylindrical substrate 10
The plasma density of the discharge space surrounded by 6 and the cylindrical cathode electrode 103 was measured. Plasma CV used in this experiment
D has the configuration shown in FIG. The plasma CVD apparatus shown in FIG. 6 is a partial modification of the plasma CVD apparatus shown in FIG. In the plasma CVD apparatus shown in FIG. 6, the cathode electrode is 103A in the axial direction of the cylindrical substrate.
(Height 75 mm), 103B (Height 230 mm), 10
3C (height 75 mm) is electrically divided into three parts. The cathode electrode 103A and the cathode electrode 10
3B, and between the cathode electrode 103B and the cathode electrode 103C, an insulating member 121A and an insulating member 121B having a height of 10 mm are arranged. 120 is a high frequency power distributor. 109A, 109B and 109C are matching circuits. The high frequency power generated by the high frequency power supply 111 is divided into three by the high frequency power dividing means 120 and supplied to the cathode electrodes 109A, 109B and 109C via the matching circuits 109A, 109B and 109C. Here, the power supply amount per unit area of the cathode electrode is 3
The power was distributed so that the two cathode electrodes would be almost equal. Other configurations are similar to those of the plasma processing apparatus shown in FIG. In this experiment, a high-frequency power source having a frequency of 40 MHz and a high frequency power source of 100 MHz was connected to the plasma processing apparatus shown in FIG.
Plasma density was measured in the same manner as. When forming the photoconductive layer, the cathode electrodes 103A and 103C are formed.
To the cathode electrode 103B, and 600 W to the cathode electrode 103B. The relationship between the position of the probe and the plasma density is plotted in FIGS. 7 and 8. As is clear from FIGS. 7 and 8, the cylindrical substrate 10 is used regardless of whether a high frequency power source with a frequency of 40 MHz is used or a high frequency power source with a frequency of 100 MHz is used.
It can be seen that the plasma density is almost uniform over the range of 358 mm or more where 6 is arranged. However,
It can be seen that the plasma density values at frequencies of 40 MHz and 100 MHz are greater when the frequency of 100 MHz is used. From the above, the following facts have been revealed. That is, the frequency of the high frequency power supply is 100M
Even in the case of Hz, the plasma density in the axial direction can be made uniform by dividing the cathode electrode into a plurality of parts in the axial direction of the cylindrical substrate.

(Experiment-5) In view of the results of Experiment-4 described above, an electrophotographic photosensitive member was produced using a plasma CVD apparatus in which a cathode electrode was divided into a plurality of parts in the axial direction of a cylindrical substrate. The characteristics of the obtained electrophotographic photosensitive member were examined.
In this experiment, the plasma CVD apparatus shown in FIG. 9 was used. The plasma processing apparatus shown in FIG. 9 is the same as the plasma processing apparatus shown in FIG.
0 and the seal flange 131 are removed. In this experiment, the frequency of the high frequency power source connected to the plasma processing apparatus shown in FIG. 9 was changed variously, and the high frequency power generated by the high frequency power source 111 was changed to the high frequency power distributor 1.
It is divided into three by 20 and matching circuits 109A, 109B, 1
09C through cathode electrodes 109A, 109B, 1
It was supplied to 09C to form a film. Specifically, Experiment-1
Samples 22a, 22b to 29a and 29b were obtained by preparing an electrophotographic photoreceptor sample under the same conditions as those of the samples 2a, 2b to 9a and 9b prepared in. In addition to this, film forming conditions were the same as those of the other samples except that a high frequency power source with a frequency of 350 MHz was used, and 30a was obtained by rotating the substrate and 30b was obtained by rotating the substrate. These samples were evaluated in the same manner as Experiment-1. The results obtained are summarized in Table 5. In the film formation of the samples 30a and 30b using a high frequency power source with a frequency of 350 MHz, abnormal discharge sometimes occurred and stable film formation could not be performed.

From the results shown in Table 5, the following was found. That is, (i) the cathode electrode is divided into a plurality of portions in the axial direction of the cylindrical substrate, and electric power is supplied to each of the divided cathode electrodes to form a film. Even when using, it is possible to suppress the film thickness unevenness in the axial direction of the cylindrical substrate to be low; (ii)
The film is formed while rotating the cylindrical substrate, and the frequency is 60
When a high frequency power source of not less than MHz and not more than 300 MHz is used, a deposited film excellent in electrophotographic characteristics can be formed at a large film forming rate of 40 μm or more; (iii) film formation while rotating a cylindrical substrate. Frequency is 200MH
When a high frequency power source of z is used, the film formation rate becomes maximum, and when the frequency is further increased, the film formation rate decreases and film thickness unevenness also increases; (iv) film formation without rotating the cylindrical substrate. If a high frequency power source having a frequency of 60 MHz or more is used, the thickness unevenness in the circumferential direction of the cylindrical substrate becomes large, and a deposited film having excellent electrophotographic characteristics cannot be formed.

(Experiment-6) From Experiment-5 described above, a high-frequency power source having a frequency of 60 MHz or more was used to form a film while rotating the cylindrical substrate to form a deposited film having excellent electrophotographic characteristics. However, in this experiment, it was examined whether or not a deposited film having excellent electrophotographic characteristics could be formed even when the cylindrical substrate was not rotated. In the present experiment, in view of the finding that the thickness unevenness in the circumferential direction of the cylindrical substrate can be suppressed to be low when the power supply to the cathode electrode obtained in the above Experiment-2 is performed from a plurality of points. , The cathode electrode was divided into a plurality of portions in the axial direction of the cylindrical substrate, and a plasma processing apparatus was formed to supply electric power from a plurality of points to each of the divided cathode electrodes to form a film. . The plasma processing apparatus used in this experiment has the configuration shown in FIG. 10, and this apparatus is a partial modification of the apparatus shown in FIG. The plasma processing apparatus shown in FIG. 10 has matching circuits 109A and 109A.
B and 109C, cathode electrodes 109A and 109B,
High-frequency power supply line 1 for supplying power to each of 109C
18A, 118B and 118C are replaced by 118A and 1 respectively.
18A, 118B, 118b, 118C, 118c, and the same configuration as that of the apparatus shown in FIG. 9 except that each cathode electrode can be supplied with electric power from two points. The contact between the high frequency power supply line 118A and the cathode electrode 103A and the high frequency power supply line 118
The contact point between a and the cathode electrode 103A is the cylindrical substrate 10
It was provided at a position symmetrical about 6. The same applies to other power supply lines and other cathode electrodes. In this experiment, using the plasma processing apparatus shown in FIG. 10, samples 2a, 2b to 9a, 9b prepared in Experiment-1 were used.
Electrophotographic photosensitive member samples were prepared under the same conditions as described in 1. above to obtain samples 32a, 32b to 39a, 39b. In addition to this, the film forming conditions were the same as those of the other samples except that a high frequency power source with a frequency of 350 MHz was used, and 40a was obtained by rotating the substrate and 40b was obtained by rotating the substrate. These samples were evaluated in the same manner as Experiment-1. About the results obtained No. 6
It is summarized in the table.

From the results shown in Table 6, the following was found. That is, (i) the cathode electrode is divided into a plurality of portions in the axial direction of the cylindrical substrate, and film formation is performed while supplying power from a plurality of points to each of the divided cathode electrodes. Thus, even when the cylindrical substrate is not rotated, the film thickness unevenness in the circumferential direction of the cylindrical substrate can be suppressed to a low level; (ii) Even when the substrate is not rotated,
By using a high frequency power source having a frequency of 60 MHz or more and 300 MHz or less, a deposited film having a large film forming rate of 40 μm or more and excellent electrophotographic characteristics can be formed; (iii) When the frequency exceeds 300 MHz, the axial direction Film thickness unevenness increases, and the electrophotographic characteristics of the electrophotographic photosensitive member obtained thereby deteriorate. (IV) From the viewpoint of film formation rate and electrophotographic characteristics, a preferable frequency range is 100 MHz to 250MHz, optimally 10
It is in the range of 0 MHz to 200 MHz.

(Experiment-7) The above Experiment-4 to Experiment-6.
As a result, when the cathode electrode was divided into a plurality of parts in the axial direction of the cylindrical substrate and electric power was supplied to each of the divided cathode electrodes to form a film, a high frequency power source having a frequency of 60 MHz or more was used. Even in the case, it was confirmed that the axial unevenness of the film thickness of the cylindrical substrate can be suppressed to a low level, and a deposited film having excellent electrophotographic characteristics can be formed at a high film forming rate. In this experiment, how to divide the cathode electrode was examined. In this experiment, first,
A high frequency power supply with a frequency of 13.56 MHz which is generally used is used, and when a power supply with this frequency is used, the length of the cathode electrode is uniform and the plasma is uniform between the cylindrical substrate and the cathode electrode. It was examined whether the density could be obtained. Specifically, the plasma processing apparatus for plasma density measurement shown in FIG. 3 is changed to an apparatus corresponding to the following two cases, and the plasma density in the region surrounded by the cylindrical substrate 106 and the cathode electrode 103 is changed. It was measured. (1) When using a cathode electrode 103 having a length of 800 mm and an inner diameter of 208 mm and an aluminum cylindrical substrate having a length of 800 mm and a diameter of 108 mm; and (2) a length of 1000 mm,
Cathode electrode 103 with inner diameter of 208 mm and length of 1000
When using an aluminum cylindrical substrate having a diameter of 108 mm and a diameter of 108 mm.

In each of the cases (1) and (2), a high-frequency power source having a frequency of 13.56 MHz was used, and a plasma density measuring probe corresponding to the cathode electrode and the cylindrical substrate of the above size was used. Experiments other than
The plasma density in the axial direction of the cylindrical substrate was measured in the same manner as described in 3. The results obtained in the case of (1) above are shown in FIG. 11 and the results obtained in the case of (2) above are shown in the form of a graph in FIG. Figure 11
From the results shown in FIG. 12 and the following, the following was found.
That is, when the length of the cathode electrode is up to 800 mm, a uniform plasma density is obtained over the entire region in the longitudinal direction of the cathode electrode, while the length of the cathode electrode is 1 mm.
If it is 000 mm, the plasma density becomes low near the center of the electrode, and a uniform plasma density is not obtained.
Therefore, the following consideration was made on the basis of the length of the cathode electrode of 800 mm.

When the cathode electrode is a cylindrical electrode having a radius a and a length l, the inductance L is given by the following equation. L = μ ₀ / 2π × [l·ln [{1+ (a ² + l ² )
^1/2 } / a]-{(a ² + l ² ) ^1/2 } -a] (where μ ₀ is the magnetic permeability of vacuum) Using this formula, a cathode electrode having a diameter of 208 mm The impedance Z (Z = ωL) of each frequency with respect to the cathode electrode length was obtained. Frequency 13.56MHz,
FIG. 13 is a graph showing the ratio of the impedance when the frequency and the cathode length are changed with the impedance when the cathode electrode length is 800 mm being 1.0. FIG.
From this, it was found that the impedance ratio was 1.0 or less in the following cases.

[0035] Frequency 60MHz: electrode length 0.33m or less Frequency 100MHz: electrode length 0.25m or less Frequency 200MHz: electrode length 0.17m or less Frequency 300MHz: electrode length 0.14m or less

Therefore, if the length of the divided cathode electrode is within the above range according to the frequency of the high frequency power source used, the plasma density is uniform between the cylindrical substrate and the cathode electrode. It has been found that a plasma can be formed.

The present invention has been completed based on the results of Experiments 1 to 6 described above. The present invention is VH
It includes an F plasma CVD method and a plasma CVD apparatus suitable for carrying out the plasma CVD method. VHF of the present invention
The plasma CVD method includes the following two modes. That is,
According to a first method aspect of the present invention, a source gas for forming a deposited film is supplied into a reaction vessel under reduced pressure, and a cathode provided around a rotatable cylindrical substrate arranged in the reaction vessel. The high frequency power generated by the VHF band high frequency power source is supplied to the electrode through the high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form a plasma on the surface of the cylindrical substrate. a VHF plasma CVD method for forming a deposited film, the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, split by said cathode - the cathode electrode Ultrashort wave energy in a frequency range of 60 MHz to 300 MHz is supplied to each of them to generate plasma in the reaction vessel to form a deposited film on the cylindrical substrate. A.

In the second method aspect of the present invention, a raw material gas for forming a deposited film is supplied into a reaction vessel under reduced pressure and is provided around a rotatable cylindrical substrate disposed in the reaction vessel. The high frequency power generated by the VHF band high frequency power source is supplied to the cathode electrode through the high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form the cylindrical substrate. A VHF plasma CVD method for forming a deposited film on a surface, wherein the cathode electrode is electrically divided into a plurality of portions in the axial direction of one cylindrical substrate, and the division is performed. Each of the cathode electrodes provided has a plurality of connection points independently connected to the high-frequency power supply means,
Frequency of 60 MHz to 300 via the connection points
Ultrashort wave energy in the range of MHz is supplied to generate plasma in the reaction vessel to form a deposited film on the cylindrical substrate. The plasma CVD apparatus of the present invention includes the following two modes. That is,
A first apparatus mode is a reaction vessel capable of depressurizing, a raw material gas supply means for supplying a raw material gas for forming a deposited film into the reaction vessel, a rotatable substrate holding means arranged in the reaction vessel, and the substrate holding. And a cathode electrode and a VHF band high frequency power source provided so as to surround a cylindrical substrate arranged in the means, and the high frequency power generated by the VHF band high frequency power source is supplied to the cathode through the high frequency power supply means. A plasma CVD apparatus for forming a deposited film on the surface of the cylindrical substrate by supplying plasma to the cathode electrode and generating plasma between the cylindrical substrate and the cathode electrode. is divided electrically into a plurality in the axial direction of one of said cylindrical body, each being divided cathode - the in each cathode electrode via the high-frequency power supply unit frequency 60MHz~3
It is characterized in that ultrashort wave energy in the range of 00 MHz is supplied.

The second apparatus mode is a reaction vessel capable of reducing pressure,
A raw material gas supply means for supplying a raw material gas for forming a deposited film into the reaction vessel, a substrate holding means arranged in the reaction vessel, and a cylindrical substrate arranged in the substrate holding means are provided so as to surround the substrate. And a cathode electrode and a VHF band high frequency power source, and the high frequency power generated by the VHF band high frequency power source is supplied to the cathode electrode through a high frequency power supply means to supply the cylindrical substrate and the cathode. A plasma CVD apparatus for forming a deposited film on the surface of the cylindrical substrate by generating plasma between the cathode electrode and the cathode electrode, wherein the cathode electrode is electrically connected in the axial direction of one of the cylindrical substrates. is divided into a plurality, each has been split cathode - each cathode electrode is independently a plurality of connection points for electrically connecting to the high-frequency power supply means, frequency 60 via a plurality of connection points
It is characterized in that ultrashort wave energy in the range of MHz to 300 MHz is supplied to each cathode electrode.

According to the plasma CVD method and the plasma CVD apparatus of the present invention having the above-described structure, the film thickness on the surface of the cylindrical substrate is extremely large in both the axial direction and the circumferential direction of the cylindrical substrate. A deposited film having a uniform and high quality can be stably formed. Further, it is possible to stably form a deposited film having excellent electrophotographic characteristics. Furthermore, it is possible to prevent the loss of the high frequency power due to the increase of the frequency of the high frequency power supply and efficiently generate the plasma, so that the deposited film can be formed at a high speed.

The present invention will be described below with reference to the drawings. The plasma CVD apparatus shown in FIG. 9 shows an example of the first aspect of the apparatus of the present invention. The plasma CVD apparatus shown in FIG. 9 is configured as follows. In FIG. 9, 100 indicates a reaction container. The reaction container 100 is a base.
Spray 101, insulating member 102A, cathode electrode 103C, insulating member 121B, cathode electrode 103B,
Insulating member 121A, cathode electrode 103A, insulating member 1
02B and the upper lid 115. 105A is a substrate holder, and the substrate holder has a heater inside.
It has a pillar 105A '. 105A "is a heater
It is a heater for heating the substrate, which is attached to the column 105A '. Reference numeral 106 denotes a cylindrical substrate arranged on the substrate holder 105A. 105B is an auxiliary holding member for the cylindrical substrate 106. The base body holder 105A is provided with a rotating mechanism (not shown) connected to the motor at its lower portion so that it can be rotated if necessary. 107
Is an exhaust pipe having an exhaust valve, and the exhaust pipe communicates with an exhaust mechanism 107 'having a vacuum pump. Reference numeral 108 is a source gas supply system including a gas cylinder, a mass flow controller, a valve, and the like. The source gas supply system 108 is connected via a gas supply pipe 117 to a gas emission pipe 116 having a plurality of gas emission holes. The raw material gas is supplied into the reaction vessel through a plurality of gas emission holes of the gas emission pipe 116. Reference numeral 111 denotes a high frequency power source, and the high frequency power generated here is supplied to the cathode electrode 103 via the high frequency power supply line 118 and the matching circuit 109. In the plasma CVD apparatus shown in FIG. 9, the cathode electrode is 10 in the axial direction of the cylindrical substrate.
3A, 103B, and 103C are electrically divided. The high-frequency power generated by the high-frequency power supply 111 is divided into three by the high-frequency power dividing means 120, and is passed through the matching circuits 109A, 109B, 109C, and then the cursors.
It is supplied to the gate electrodes 109A, 109B and 109C. 1
Reference numeral 04 is a shield wall.

In the plasma CVD apparatus of the present invention, the division length for electrically dividing the cylindrical cathode electrode into a plurality of portions depends on the diameter of the cathode electrode and the frequency of the high frequency power source used. For example, if the inner diameter of the electrode is 208 mm,
The length of the divided cathode is 3 at a frequency of 60 MHz.
30 mm or less, 250 mm or less at frequency 100 MHz, 170 mm or less at frequency 200 MHz, frequency 3
At 00 MHz, it is desirable to set it to 140 mm or less. The number of divided electrodes depends on the size of the cylindrical substrate,
When a cylindrical substrate having an inner diameter of 208 mm and a length of 358 mm is used, it is desirable that the frequency is 60 MHz or more, the frequency 100 MHz is 2 or more, the frequency 200 MHz is 3 or more, and the frequency 300 MHz is 3 or more. When a plurality of cylindrical substrates are stacked to form a deposited film, a value obtained by dividing the total length of the stacked substrates by the maximum value of the above-mentioned divided cathode lengths is represented by one decimal place. It is desirable to round up and set the number of divisions to an integer value or more. In the plasma CVD apparatus shown in FIG. 9, the high frequency power generated by the high frequency power supply 111 is supplied to the power distributor 12
0 and supply to the cathode electrode.
It is also possible to provide a plurality of high frequency power supplies 111A, 111B and 111C without providing a power distributor as shown in FIG.

FIG. 10 shows an example of the second aspect of the plasma CVD apparatus of the present invention. The plasma CVD apparatus shown in FIG. 10 has matching circuits 109A, 109B, 1
09C, cathode electrodes 109A, 109B, 109
High frequency power supply line 118 for supplying power to C respectively
A, 118B and 118C are replaced by 118A and 118C, respectively.
The apparatus has the same configuration as that of the apparatus shown in FIG. 9 except that the cathode electrodes a, 118B, 118b, 118C, and 118c are branched so that the respective cathode electrodes are supplied with power from two points. The plasma CVD apparatus shown in FIG.
FIG. 15 is a sectional view taken along the line. In FIG. 15, the power distributor is omitted, but after passing through the matching circuit 109A, the branched power supply line 118A and the power supply line 118 are branched.
a is 150 A and 150 a, respectively, and is the cathode electrode 10.
It is connected to 3A. The connection point to the cathode electrode is shown in Fig. 16.
As shown in FIG. 17, three points of 150D, 150E, and 150F can be set, or as shown in FIG.
It is also possible to set four points of 150E, 150F, and 150G. The number of connection points is preferably two or more, and it is desirable to appropriately increase the number according to the diameter of the cathode electrode used.
It is desirable that the connection points be provided at positions symmetrical with respect to each other with respect to the cathode electrode.

The plasma CVD method of the present invention is performed as follows. An example of using the plasma CVD apparatus shown in FIG. 9 will be described. After the cylindrical substrate 106 is set on the substrate holder 105A, the inside of the reaction container 100 is evacuated by operating the exhaust mechanism 107 ', and the inside of the reaction container 100 is depressurized to a desired pressure. Then, the heater 105A ″ is energized to heat and maintain the substrate 106 at a desired temperature.
The raw material gas is supplied from the raw material gas supply system 108 via the gas supply pipe 117 and the gas discharge pipe 116 to the reaction vessel 10.
0, and the inside of the reaction vessel is adjusted to a desired pressure.
In such a place, the frequency 60
A high frequency of MHz to 300 MHz is generated, the high frequency power is divided by the high frequency power distributor 120, and the matching circuit 109
It is supplied to the cathode electrodes 103A, 103B and 103C via A, 109B and 109C, respectively. Thus, in the space surrounded by the cylindrical substrate 106 and the cathode electrode, the source gas is decomposed by the high frequency energy to generate active species, which causes the formation of a deposited film on the cylindrical substrate 106.

In the present invention, the electric power supplied to each of the divided cathode electrodes is preferably such that the electric energy per unit area of the electrode is equal for each cathode electrode. The amount of power per hit can be different. Any specific power can be adopted as long as it can generate plasma.
Preferably ^{0.001W / cm 2 ~10W / cm 2} , more preferably it is desirable to ^{0.01W / cm 2 ~5W / cm 2} .

In the present invention, the frequency of the high frequency power source is
Preferably 60 MHz to 300 MHz, more preferably 100 MHz to 250 MHz, optimally 100 MHz to
The range of 200 MHz is desirable in consideration of the film forming rate and film quality.

In carrying out the method of the present invention, known gases can be appropriately selected as the gas to be used. For example, in the case of forming an a-Si-based functional deposited film, silane, disilane, higher order silane, or the like or a mixed gas thereof is mentioned as a preferable source gas. If another functional deposited film is to be formed, for example, germane,
Source gases such as methane and ethylene, or a mixed gas thereof can be used.

Examples of the carrier gas used when the source gas is supplied using the carrier gas include hydrogen or an inert gas such as argon or helium.

As the characteristic improving gas for changing the band gap width of the deposited film, for example, a gas containing a nitrogen atom such as nitrogen or ammonia, a gas containing an oxygen atom such as oxygen, nitric oxide or nitrous oxide, Methane, ethane, ethylene,
Hydrocarbon gases such as acetylene and propane, gaseous fluorine compounds such as silicon tetrafluoride, disilicon hexafluoride and germanium tetrafluoride, and mixed gases thereof can be used.

Examples of the dopant gas for the purpose of doping include diborane, boron fluoride, phosphine, phosphorus fluoride and the like.

The pressure inside the reaction vessel at the time of film formation may be any pressure as long as it is a pressure at which plasma is generated.
When forming a -Si film, it is preferably 5 Torr or less, more preferably 0.1 mTorr to 3 Torr, and most preferably 0.3 mTorr to 500 mTorr.

The substrate temperature at the time of forming the deposited film can be set as appropriate, but when forming an amorphous silicon-based deposited film, it is preferably 20 ° C. to 500 ° C., more preferably 5 ° C.
It is desirable that the temperature is 0 ° C to 450 ° C.

[0053]

The present invention will be described in detail below with reference to specific examples, but the present invention is not limited to these examples.

(Example 1) The apparatus shown in FIG. 9 is used as the high frequency power source 111 of the apparatus shown in FIG. Film formation was performed under the conditions, and an amorphous silicon film was deposited on the substrate to manufacture an electrophotographic photosensitive member.

As the base 106, an Al cylindrical base having a diameter of 108 mm and a length of 358 mm was used. The film formation was performed as follows. That is, after the Al-made cylindrical substrate 106 is set on the substrate holder 105A, the inside of the reaction container 100 is evacuated using the exhaust mechanism 107 ', and the inside of the reaction container 100 is 1 ×.
The pressure was adjusted to 10 ^-6 Torr. Then, the base 106
And the heater 105A ″ was energized to heat and maintain the substrate 106 at a temperature of 250 ° C. Next, from the source gas supply system 108, via the gas supply pipe 117 and the gas release pipe 116, Gas was introduced into the reaction vessel under the conditions shown in Table 7, and the pressure inside the reaction vessel was adjusted to 50 mTorr.
Then, high frequency was generated, and high frequency power was supplied to each cathode electrode as shown in Table 7. In this way, the charge injection blocking layer, and then the photoreceptive layer including the photoconductive layer and the surface protective layer were formed in about 30 minutes in total, to prepare an electrophotographic photoreceptor. This film forming operation was repeated to obtain 5 electrophotographic photosensitive members. Each of the obtained photoreceptors was evaluated for charging ability and image density in the same manner as in Experiment-1. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

(Comparative Example 1) Instead of the apparatus shown in FIG.
Using the apparatus of FIG. 1 in which the cathode electrode is composed of a single unit having a diameter of 208 mm and a length of 400 mm, an electric power of 800 W is applied from one place after the charge injection blocking layer is formed, and a photoconductive layer of 1000 W is formed. Film formation was carried out in the same manner as in Example 1 except that the electric power of 1 was applied from one location to prepare 5 electrophotographic photosensitive members. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. As a result, it was found that none of the electrophotographic photoconductors had considerable charging ability unevenness and image unevenness and could not be put to practical use.

(Embodiment 2) Instead of the device shown in FIG. 9, the device shown in FIG. 10 is used in which power is supplied to each of the cathode electrodes 103A, 103B and 103C from two connection points. Five electrophotographic photosensitive members were prepared in the same manner as in Example 1 except for the above. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. as a result,
All electrophotographic photoreceptors showed excellent results for all evaluation items. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

Example 3 Five electrophotographic photosensitive members were prepared in the same manner as in Example 2 except that the cylindrical substrate 106 was not rotated. Experiment on each of the obtained photoreceptors-
The same evaluation as in 1 was performed. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items.
From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

(Example 4) Five electrophotographic photosensitive members were produced in the same manner as in Example 1 using the apparatus shown in FIG. The device shown in FIG. 18 differs from the device shown in FIG. 9 in that the cathode electrode is divided into two electrodes 103A and 103B. Here, the cathode electrodes 103A and 103B are respectively 208 mm in diameter and 195 mm in length.
Composed of. The same electric power is applied to the cathode electrodes 103A and 103B (at the time of forming the charge injection blocking layer and the surface protection layer, 40
Five electrophotographic photosensitive members were produced in the same manner as in Example 1 except that 0 W and 500 W when supplying the photoconductive layer were supplied. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

Example 5 Five electrophotographic photosensitive members were produced in the same manner as in Example 4 using the apparatus shown in FIG. The apparatus shown in FIG. 19 is different from the apparatus shown in FIG. 18 in that cathode electrodes 103A and 103B are provided with 18A and 1A, respectively.
18a and 118B, 118b are different in that power is supplied from two power supply lines. Further, at this position, the contact point between the power supply line and the cathode electrode is designed to be symmetrical with respect to the base body. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

Example 6 Five electrophotographic photosensitive members were produced in the same manner as in Example 5 except that the cylindrical substrate 106 was not rotated. Experiment on each of the obtained photoreceptors-
The same evaluation as in 1 was performed. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items.
From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

(Example 7) An electrophotographic photosensitive member was produced in the same manner as in Example 1 using the apparatus shown in FIG. Figure 20
The device shown in FIG. 9 differs from the device shown in FIG. 9 in that the cathode electrode is divided into four cathode electrodes 103A, 103B, 103C and 103D.
A, 103B, 103C and 103D each have a diameter of 2
The length is 08 mm and the length is 92.5 mm. Electric power equal to that of the cathode electrodes 103A, 103B, 103C and 103D (200 W when the charge injection blocking layer and the surface protection layer are formed,
Five electrophotographic photosensitive members were produced in the same manner as in Example 1 except that 250 W) was supplied when the photoconductive layer was formed. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

Example 8 An electrophotographic photosensitive member was manufactured in the same manner as in Example 7 using the apparatus shown in FIG. The apparatus shown in FIG. 21 is different from the apparatus shown in FIG. 20 in that the cathode electrodes 103A, 103B, 103C and 103D are provided with 18A, 118a, 118B, 118b and 118, respectively.
They are different in that power is supplied from two power supply lines C, 118c, 118D and 118d, and the contacts between the power supply line and the cathode electrode are arranged in symmetrical positions with respect to the base body. ing. The same evaluation as in Experiment-1 was performed for each of the obtained photoreceptors. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items. From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

Example 9 Five electrophotographic photosensitive members were produced in the same manner as in Example 8 except that the cylindrical substrate 106 was not rotated. Experiment on each of the obtained photoreceptors-
The same evaluation as in 1 was performed. As a result, all electrophotographic photosensitive members showed excellent results for all evaluation items.
From this, it was found that all the electrophotographic photosensitive members had excellent electrophotographic characteristics.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Table 6]

[0071]

[Table 7]

[0072]

As described above, according to the plasma CVD method and the plasma CVD apparatus of the present invention, the cylindrical substrate is extremely excellent in both the axial direction and the circumferential direction on the surface of the cylindrical substrate. It is possible to stably form a deposited film having a uniform film thickness and a high film quality. Further, it is possible to stably form a deposited film having excellent electrophotographic characteristics. Furthermore, it is possible to prevent the loss of the high frequency power due to the increase of the frequency of the high frequency power supply and efficiently generate the plasma, so that the deposited film can be formed at a high speed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a conventional plasma CVD apparatus.

FIG. 2 is a schematic diagram showing a plasma CVD apparatus obtained by partially modifying the plasma CVD apparatus of FIG. 1 for an experiment.

FIG. 3 is a schematic diagram showing a plasma CVD apparatus obtained by partially modifying the plasma CVD apparatus of FIG. 1 for an experiment.

FIG. 4 40 MHz in a conventional plasma CVD apparatus
5 is a graph of the results of measuring the plasma density in the case of using electric power of the frequency of 1 above in relation to the position of the cylindrical substrate.

FIG. 5: 100 MH in a conventional plasma CVD apparatus
It is a graph of the result of having measured the plasma density in the case of using the electric power of the frequency of z with respect to the position of a cylindrical substrate.

FIG. 6 is a plasma CVD apparatus according to the present invention (for experiment)
It is a schematic diagram which shows.

FIG. 7 is 40 MHz in the plasma CVD apparatus of FIG.
5 is a graph of the results of measuring the plasma density in the case of using electric power of the frequency of 1 above in relation to the position of the cylindrical substrate.

FIG. 8 shows a plasma CVD apparatus of FIG.
It is a graph of the result of having measured the plasma density in the case of using the electric power of the frequency of z with respect to the position of a cylindrical substrate.

FIG. 9 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 10 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 11 is a graph showing the results of measuring the plasma density in relation to the position of the cylindrical substrate in the case where electric power having a frequency of 13.56 MHz is used in the plasma device obtained by partially modifying the device of FIG.

FIG. 12 is a graph in which the plasma density in the plasma CVD apparatus is plotted with respect to the position of the cylindrical substrate.

FIG. 13 is a graph showing the relationship between the length of the cathode electrode and the impedance in the case of using a high frequency power source of various frequencies.

FIG. 14 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 15 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 16 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 17 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 18 is a schematic view showing an example of a plasma CVD apparatus of the present invention.

FIG. 19 is a schematic view showing an example of a plasma CVD apparatus of the present invention.

FIG. 20 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

FIG. 21 is a schematic diagram showing an example of a plasma CVD apparatus of the present invention.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI G03G 5/082 G03G 5/082 H01L 21/31 H01L 21/31 C 31/08 31/08 Q (56) Reference JP-A-60-148108 (JP, A) JP-A-5-32489 (JP, A) JP-A-4-100215 (JP, A) JP-A-2-225674 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) H01L 21/205 B01J 19/08 C23C 16/24 C23C 16/509 C23C 16/52 G03G 5/082 H01L 21/31 H01L 31/08

Claims (23)

(57) [Claims] 1. A VHF band high frequency wave is supplied to a cathode electrode provided around a rotatable cylindrical substrate disposed in the reaction vessel by supplying a raw material gas for film formation into the reaction vessel under reduced pressure. VHF for supplying high-frequency power generated by a power source through high-frequency power supply means to generate plasma between the cylindrical substrate and the cathode electrode to form a deposited film on the surface of the cylindrical substrate. a plasma CVD method, the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, split by said cathode - the high-frequency power supplied to each of the cathode electrode Through the means microwave energy in the frequency range of 60 MHz to 300 MHz
Is supplied to generate a plasma in the reaction vessel to form a deposited film, which is a VHF plasma CVD method. 2. The microwave energy per unit area of the cathode electrode supplied to the cathode electrode is controlled to be substantially equal for each electrode.
VHF plasma CVD method described in 1. 3. The microwave energy is 0.001 W / cm ^{2 to} 10 W / per unit area of the cathode electrode.
The VHF plasma CVD method according to claim 1, which is supplied in a range of cm ² . 4. The VHF plasma CVD method according to claim 1, wherein the pressure in the reaction vessel at the time of forming the deposited film is maintained at 5 Torr or less. 5. The VHF plasma CV according to claim 1, wherein the cylindrical substrate is maintained at a temperature of 20 ° C. to 500 ° C.
Method D. 6. The VHF plasma CVD method according to claim 1, wherein the deposited film is a silicon-based deposited film. 7. The VHF plasma CVD method according to claim 6, wherein the deposited film is for an electrophotographic photoreceptor. 8. A VHF band high frequency wave is supplied to a cathode electrode provided around a rotatable cylindrical substrate arranged in the reaction vessel by supplying a raw material gas for film formation into the reaction vessel under reduced pressure. VHF for supplying high-frequency power generated by a power source through high-frequency power supply means to generate plasma between the cylindrical substrate and the cathode electrode to form a deposited film on the surface of the cylindrical substrate. a plasma CVD method, the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, split by said cathode - RF respective cathode electrode is independently It has a plurality of connection points for connecting to an electric power supply means, and supplies microwave energy in a frequency range of 60 MHz to 300 MHz through the plurality of connection points to generate plasma in the reaction vessel to form a deposited film. That Characteristic VHF plasma CVD
Law. 9. The microwave energy per unit area of the cathode electrode supplied to the cathode electrode is controlled to be substantially equal for each electrode.
VHF plasma CVD method described in 1. 10. The microwave energy is the energy of the cathode.
0.001 W / cm ^{2 to} 10 W per unit area of the electrode
The VHF plasma CVD method according to claim 8, wherein the VHF plasma CVD method is supplied in the range of / cm ² . 11. The VHF plasma CVD method according to claim 8, wherein the pressure in the reaction vessel when forming the deposited film is maintained at 5 Torr or less. 12. The cylindrical substrate is 20 ° C. to 500 ° C.
9. The VHF plasma C according to claim 8, which is maintained at a temperature of
VD method. 13. The VHF plasma CVD method according to claim 8, wherein the deposited film is a silicon-based deposited film. 14. The VHF plasma CVD method according to claim 13 , wherein the deposited film is for an electrophotographic photoreceptor. 15. A reaction vessel capable of reducing the pressure, a source gas supply means for supplying a source gas for forming a deposited film into the reaction vessel,
A rotatable substrate holding means arranged in the reaction container, a cathode electrode provided so as to surround a cylindrical substrate arranged in the substrate holding means, and a VHF band high frequency power source, and the VHF band. The high frequency power generated by the high frequency power source is supplied to the cathode electrode through the high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form a surface on the cylindrical substrate. A plasma CVD apparatus for forming a deposited film on the cathode electrode, wherein the cathode electrode is
Electrically divided into a plurality in the axial direction of one of said cylindrical body, divided by the the cathode - via the high-frequency power supply means to each of the cathode electrode frequency 60MHz~300
A plasma CVD apparatus characterized in that it supplies ultra-short wave energy in the range of MHz. 16. The plasma CVD apparatus according to claim 15, wherein the divided cathode electrode has a cylindrical shape. 17. The plasma CV according to claim 15, wherein the length of the divided cathode electrode is 330 mm or less.
D device. 18. The plasma CVD apparatus according to claim 15, wherein the ultra-high frequency energy is divided into a plurality of pieces by a power distributor and supplied to the divided cathode electrodes. 19. A reaction vessel capable of reducing the pressure, a source gas supply means for supplying a source gas for forming a deposited film into the reaction vessel,
The substrate holding means arranged in the reaction vessel, the cathode electrode provided so as to surround the cylindrical substrate arranged in the substrate holding means, and the VHF band high frequency power source, the VH
The high frequency power generated by the F band high frequency power supply is supplied to the cathode electrode through the high frequency power supply means, and plasma is generated between the cylindrical substrate and the cathode electrode to form the cylindrical substrate. Plasma CV that forms a deposited film on the surface
A D device, the cathode - cathode electrode is electrically divided into a plurality in the axial direction of one of said cylindrical body, each being divided cathode - each cathode electrode is independently a high frequency power supply means Has a plurality of connection points to be electrically connected to, and a frequency of 60 MHz to 300 MH via the plurality of connection points.
A plasma CVD apparatus characterized in that ultrashort wave energy in the range of z is supplied to each cathode electrode. 20. The plasma CVD apparatus according to claim 19, wherein the connection points are arranged symmetrically with respect to the cylindrical substrate. 21. The plasma CVD apparatus according to claim 19, wherein the divided cathode electrode has a cylindrical shape. 22. The plasma C according to claim 21, wherein the height of the divided cathode electrodes is 330 mm or less.
VD device. 23. The plasma CVD apparatus according to claim 19, wherein the microwave energy is divided into a plurality of pieces by a power divider and is supplied to the divided cathode electrodes.