JP2000305300A - Photoconductive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoconductive element free from exfoliation between an electroconductive substrate and a photoconductive film by providing an adhesion- reinforcing film between the electroconductive substrate and the photoconductive film. SOLUTION: A photoconductive film 3 which is an amorphous film based on silicon atoms is provided on an electroconductive substrate 2, and a surface protecting film 4 is laminated on the photoconductive film 3. Further, an adhesion-reinforcing film 5 is added between the electroconductive substrate 2 and the photoconductive film 3. The adhesion-reinforcing film 5 is an amorphous a-Si:N film containing silicon as a main component and at least nitrogen atoms. It is preferable that the film thickness of the adhesion-reinforcing film 5 is in the range of 300 to 10,000 Å when the content of nitrogen atom is in the range of 20 to 55% and in the range of 300 to 3,000 Å when the content of nitrogen atom is in the range of 55 to 57%. Though the adhesion-reinforcing film 5 can be formed using a polycrystalline material or a single crystalline material, it is preferable to form the adhesion-reinforcing film 5 of an amorphous material because the same production facilities as that used in the production of the photoconductive film 3 and the surface protecting film 4 can be used and the adhesion to each other becomes stronger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive member used in a copying machine or a printer using electrophotography, a silicon sensor light receiving element in an image sensor, or a photoconductive element used in a solar cell or the like. It is.

[0002]

2. Description of the Related Art As a photoconductive element used in an electrophotographic copying machine or a printer, for example, a photoconductive element having a structure as shown in FIG. 2 has been proposed. In the figure, 1 is a photoconductive element, 2 is a conductive substrate, 3 is a photoconductive film, 4 is a surface protective film, and the photoconductive film 3 and the surface protective film 4 are formed of an amorphous material. Then, the photoconductive element 1 having this laminated structure
When the photoconductive film 3 absorbs light, the electrical conductivity increases due to the photoconductive effect, and a photocurrent can be obtained by applying a voltage to the conductive substrate 2.

The conductive substrate 2 is generally made of an aluminum material, but in a special case, a transparent electrode made of ITO, SnO ₂ , ZnO or the like is formed on an insulating material such as glass or plastic. The photoconductive film 3 is a film in which at least one or more photoconductive layers having photosensitivity characteristics are laminated. The surface protective film 4 is a film that protects the photoconductive film 3 from moisture, NOx oxidation, and external stress.

The photoconductive element 1 having such a structure uses amorphous silicon (a-Si). However, H ₂ is used to reduce dangling bonds, and H ₂ is used to improve the charge holding function. Is doped with an appropriate amount of boron, and a film is formed by decomposing a SiH ₄ (silane) gas by a method such as RF glow discharge. The dark resistivity can be increased to 10 ¹¹ to 10 ¹³ Ωcm or more. Can be applied to the copying process.

[0005]

However, in the above-described photoconductive element, there has often been a problem that the photoconductive film is partially or entirely separated from the conductive substrate. Causes for this are that the surface shape of the conductive substrate is rough (rough), the surface of the conductive substrate is uneven due to insufficient cleaning, adhesion of foreign matter, scratches, etc. It is conceivable that stress is applied due to stress.

It is possible to take countermeasures against all of these factors so that they do not occur, but there is a problem that it takes too many steps. In addition, this type of peeling occurs during film formation, occurs several hours after film formation, and occurs several days after film formation, which makes it more difficult to determine the cause.

The present invention has been made in view of the above problems, and has as its object to provide a photoconductive element in which the conductive substrate and the photoconductive film are not separated.

[0008]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, there is provided a photoconductive element in which a photoconductive layer of an amorphous film containing silicon atoms as a base is provided on a substrate. The object of the present invention is to solve the problem by providing a photoconductive element characterized in that an adhesion strengthening film is provided between a substrate and an amorphous film.

[0009] Further, the adhesion enhancement film is characterized in that silicon is a main component and at least nitrogen atoms are contained.

Further, the adhesion enhancing film is amorphous.

When the nitrogen atom content is 20 to 55%, the adhesion reinforcing film has a thickness of 300 to 10000 °.
And when the nitrogen atom content is 55 to 57%, the film thickness is 300 to 3000 °.

[0012]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, and the same reference numerals as those in FIG. 2 denote the same components.

In FIG. 1, reference numeral 2 denotes a conductive substrate, which is generally made of aluminum as described in the conventional example. As a special example, ITO, a transparent insulating plate such as glass, acrylic, or plastic is used. A film formed of a transparent electrode such as SnO ₂ or ZnO is also used.

In FIG. 1, reference numeral 3 denotes an amorphous photoconductive film mainly composed of silicon atoms, which changes the sensitivity to a single layer or each wavelength of light or injects carriers from the conductive substrate 2 side. It has a structure in which a plurality of layers having different functions, such as for preventing the occurrence of pits, are laminated. Reference numeral 4 denotes a surface protective film laminated on the photoconductive film 3 for protecting the photoconductive film 3 from the influence of moisture, NOx, oxidation or external stress. The configuration up to this point is the same as the conventional one, but in the present invention, in addition to these, an adhesion strengthening film 5 is added between the conductive substrate 2 and the photoconductive film 3 which is the amorphous film. The adhesion reinforcing film 5 is an a-Si: N film containing silicon as a main component and containing at least nitrogen.

In order to confirm the performance of the photoconductive element 1 of the present invention configured as described above, the inventors conducted a test described below to form the adhesion reinforcing film 5 with the conductive substrate 2 and the amorphous film. It has been clarified that the provision between the photoconductive film 3 prevents the conductive substrate 2 and the photoconductive film 3 from peeling off.

In order to confirm the effect of preventing peeling, the inventors first prepared a sample as follows. That is, first, 24 conductive bases 2 were prepared, and a group of photoconductive elements for implementing the present invention was set to Group A, and a group of conventional photoconductive elements was set to Group B. Twelve in Group A were formed with an adhesion enhancing film, a photoconductive film, and a surface protective film on a conductive substrate, and in Group 12, 12 were formed with a photoconductive film and a surface protective film on a conductive substrate.

The film was formed under the same conditions including the cleaning conditions. That is, approximately 30 as a photoconductive film (amorphous film).
A film having a thickness of μm was formed to a thickness of about 3000 ° as a surface protective film. The adhesion strengthening film was an a-Si: N film having a silicon to nitrogen ratio of 1: 1 and was formed to a thickness of about 3000 °.

In order to determine the peeling effect of the sample in a short time, a test was performed under more severe conditions than those usually used (accelerated test). That is, although the cleaning of the conductive substrate is performed in two steps of ordinary rough cleaning and finish cleaning, only rough cleaning is performed, and the finish cleaning is omitted, and the temperature and humidity are set to a higher temperature and a higher humidity. It was confirmed that no peeling occurred in any of the completed samples of Group A and Group B. The test was conducted under the following conditions in consideration of the above.

The samples of Group A and Group B were placed in an environment of a temperature of 80 ° C. and a humidity of 90%, and the peeling state of the samples was observed every predetermined time. That is, after 2 hours, 24 hours, 48 hours, 100
After 0 hour, it was examined for peeling. Table 1 summarizes the results.

[0020]

[Table 1]

From the above results, all the samples in Group B, which is a conventional photoconductive element, were peeled off within 24 hours. There was no peeling even after hours. The samples of group B all failed within 24 hours. However, as described above, the samples were not defective from the beginning, but those that were good at first became defective as a result of the accelerated test. Things.

Next, in order to examine the adhesion between the substrate of the a-Si: N film as the adhesion reinforcing film and the photoconductive film as the amorphous film, the film thickness and the element content (atm%) of the adhesion reinforcing film were determined. At a high temperature and a high humidity (8%) as in the above embodiment.
(0 ° C., 90%) was examined for the state of peeling after leaving for 1000 hours. Table 2 summarizes the results.

As shown in Table 2, the thickness of the a-Si: N film is 100, 300, 1000, 3000, 7000, 1
0000, 15000 °, and the ratio of the content of Si and N (atm%) was changed in a matrix form from 43:57 to 85:15.

[0024]

[Table 2]

In Table 2, "O" indicates that no peeling occurred between the substrate and the photoconductive film after the above test, and "X" indicates that peeling occurred between the substrate and the photoconductive film. is there.

Table 3 shows the inspection results of the photoconductor electrical characteristics (charge potential, sensitivity, etc.) and image characteristics of the photoconductive element produced as described above.

[0027]

[Table 3]

In Table 3, "O" indicates that there is no problem in both the electrical characteristics and image characteristics, and "X" indicates that there is a problem in one or both of the electric characteristics and the image characteristics.

From the above test results, it was found that a-
The Si: N film has a content ratio of Si and N of 45:55 to 55:55.
When the ratio is 80:20, the film thickness is preferably 300 to 10000 °, and when the content ratio of Si and N is 43:57 to 45:55, the film thickness is 300 to 3000 °. A photoconductive element having good characteristics can be formed.

In the above embodiment, since the photoconductive film 3 and the surface protective film 4 are formed of an amorphous material, the adhesion reinforcing film 5 is also formed of an amorphous material similar to these. However, the present invention is not limited to this, and the adhesion strengthening film 5 can be formed of a polycrystalline material or a single-crystal material.

However, when the adhesion strengthening film 5 is formed of an amorphous material, the same apparatus as that for manufacturing the photoconductive film 3 and the surface protective film 4 can be used, and continuous film formation is possible. It can be simplified. In addition, bonding of similar amorphous materials and continuous film formation enhance the mutual adhesion.

[0032]

As described above, by providing the adhesion enhancing film 5 between the conductive substrate 2 and the photoconductive film 3, there is an effect that the peeling between the conductive substrate 2 and the photoconductive film 3 does not occur.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment according to the present invention.

FIG. 2 is a sectional view showing a conventional configuration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Photoconductive element 2 ... Conductive base 3 ... Photoconductive film 4 ... Surface protective film 5 ... Adhesion enhancement film

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Fumiyuki Suda 400 Soya, Hadano-shi, Kanagawa Stanley Electric Co., Ltd. Hadano Works F-term (reference) 2H068 DA57 DA64 DA67 FA08

Claims (5)

[Claims] 1. A photoconductive element in which a photoconductive film of an amorphous film containing silicon atoms as a base is provided on a substrate, wherein an adhesion enhancing film is provided between the substrate and the photoconductive film. Conductive element. 2. The adhesion strengthening film contains silicon as a main component,
2. The photoconductive device according to claim 1, wherein the photoconductive device contains at least a nitrogen atom. 3. The photoconductive element according to claim 1, wherein said adhesion enhancing film is amorphous. 4. The adhesion enhancing film has a nitrogen atom content of 2%.
4. The photoconductive element according to claim 2, wherein the thickness is from 300 to 10000 [deg.] At 0 to 55%. 5. The adhesion enhancing film has a nitrogen atom content of 5%.
4. The photoconductive element according to claim 2, wherein the thickness is 300 to 3000 [deg.] At 5 to 57%.