JPH0234787A - Laminated body having carbon-based coating film - Google Patents

Abstract

PURPOSE:To solve problems due to mechanical stress and static electricity and to satisfy transparency by forming a carbon-based coating film contg. halogen, nitrogen and hydrogen by CVD on the surface of a substrate. CONSTITUTION:The surface of a substrate of a metal, glass, ceramics, org. resin, etc., is coated with a carbon-based coating film contg. about 0.1-50atomic% halogen and nitrogen or hydrogen, halogen and nitrogen by plasma CVD to form a laminated body. A fluorine compd. is preferably utilized as a halogen source in consideration of the corrosion of the inner wall of a reaction chamber. Such characteristics of the coating film as the electrical conductivity, hardness and transmissivity can easily be varied by varying discharge parameters such as the flow rates of starting materials for carbon, halogen and nitrogen, impressed electric power, pressure during reaction and the shape of a discharge vessel. The service life of the laminated body can be prolonged and the reliability can be improved.

Description

Detailed Description of the Invention "Field of Application of the Invention" The present invention aims to simultaneously solve mechanical stress resistance and static electricity countermeasures on the surfaces of glass, metals, ceramics, organic resins, etc. The present invention relates to a composite body having a carbon-based coating, which is coated with a transparent carbon-based coating.

``Prior art'' Coating the surface of relatively soft materials such as glass, metal, plastic, resin, etc. with a film that is harder than those soft materials is effective against mechanical stresses such as abrasion and scratches. It is.

Such membranes include A1. Off, TiN, BN,
Inorganic films such as WC, SiC, Si, Na, SiO□, and "composite having a carbon film" filed by the present inventor (Patent Application No. 146930 of 1982) are known. However, the above-mentioned known protective film already has high electrical resistivity, tends to generate static electricity, and tends to attract dirt and dust in the atmosphere to its surface. In addition, when used in composite materials that actively apply an electric field and utilize static electricity, such as photoreceptors used in electrophotographic processes, charges accumulate in the protective film with high electrical resistance. However, there was a problem that the expected performance could not be achieved for a long period of time.

One possible way to solve such problems is to add a conductive substance to the known film.

In this case, the added conductive substance becomes a light absorption center,
Light absorption occurs in the known protective film, making it unsuitable for applications requiring transparency in the infrared and visible ranges.

Furthermore, depending on the conditions of the film forming process, the known protective film has the problem of accumulation of internal stress and peeling of the film. Therefore, it is necessary to take measures such as thinning the film thickness or providing an intermediate layer between the protective film and the underlying material to improve adhesion, but a reduction in film thickness means a reduction in mechanical stress resistance. However, the presence of an intermediate layer causes the problem of increased costs due to increased processes.

"Structure of the Invention" The purpose of the present invention is to solve the above-mentioned problems and to simultaneously satisfy mechanical stress resistance as a protective film, problems arising from static electricity, and transparency. Zero halogen element and nitrogen or hydrogen, halogen element and nitrogen in the coating
．． 1 to 50 atomic percent added, and the substrate surface is coated with a film mainly composed of carbon to which the halogen element and nitrogen or halogen element, nitrogen, and hydrogen are added. An object of the present invention is to provide a composite having a coating.

The coating mainly composed of carbon to which a halogen element and nitrogen are added is used in the composite according to the present invention.
4) It can be formed by introducing a hydrocarbon such as acetylene (czH) into plasma, decomposing and exciting the carbon raw material, and depositing it on a predetermined substrate. At this time, at the same time, N F s is used as a raw material for the halogen element,
Fluorides such as SF, W F b, chlorides such as CCL,
Bromides such as CH, Br, or NH, N2, etc. as raw materials for iodide nitrogen are introduced into the plasma to produce F, CI, Br.
, I, etc. and nitrogen are added. The amount added can be controlled by the flow rate of the substance containing the halogen element and nitrogen. Here, as a raw material gas containing carbon,
In addition to the above-mentioned hydrocarbons, fluorinated carbons such as CF, CHz F 2 and the like, chlorinated carbons such as CC14, and brominated hydrocarbons such as CH and Br may be used.

However, as the halogen element, fluorine and nitride are most easily used due to the problem of corrosion of the walls of the plasma reaction chamber. Furthermore, from the viewpoint of controlling the amounts of halogen elements and nitrogen added, hydrocarbons that do not contain fluorine and nitrogen are effective as carbon raw materials.

The film according to the present invention is produced by introducing the above-mentioned raw materials, that is, a carbon raw material, a halogen element, and a nitrogen raw material into a plasma reaction chamber at the same time, and at this time adjusting the flow rates of the halogen-based raw material and the nitrogen raw material. By this, the amount of halogen element and nitrogen added to the film can be controlled.

The amounts of halogen elements and nitrogen added are observed as differences in conductivity, transmittance, and hardness. The experimental results of changes in electrical conductivity when the flow rates of halogen elements and nitrogen source materials are changed are shown below.

N F x was used as the halogen element and nitrogen source material. Ethylene was used as the carbon raw material, the ethylene flow rate was 11003 CC, the reaction pressure was 10 Pa, and the input power density was 0.
08W/cm". As shown in Figure 1, N F z
As the amount of NH's increases, the conductivity increases. In addition, as shown in Figure 2, as the flow rate of NF and N Hz increases, the permeability increases (becomes higher).Furthermore, as shown in Figure 3, as the flow rate of NF and N H3 increases, the hardness decreases.Hardness In other words, a decrease in internal stress means a decrease in internal stress.

By using a film whose main component is a halogen element and nitrogen, or carbon to which a halogen element, nitrogen, and hydrogen are added, it is possible to change the conductivity, hardness, and transmittance of the film over a relatively wide range, as described above. can. That is, as described above, the optimal characteristics required for various applications can be obtained by changing the amounts of halogen elements and nitrogen added by changing the flow rates of 6 or more halogen elements and nitrogen raw materials, which can be easily obtained at relatively low cost. Of course, the power input during discharge, the reaction pressure,
Discharge conditions such as the shape of the discharge vessel and the flow rate of the carbon raw material are constant. Further, even if one or more of these discharge conditions are changed, the amounts of the halogen element and nitrogen added can be changed.

- As an example, FIG. 4 shows the change in conductivity when the input power is changed. That is, as the input power increases, the conductivity increases. In this case, of course, the discharge parameters other than the input power are the reaction pressure, the shape of the discharge vessel, NF, and NH.
, flow rate, C, H, flow rate, etc. are constant.

As mentioned above, the film properties such as electrical conductivity, hardness, and transmittance of a film whose main components are a halogen element and nitrogen or hydrogen, a halogen element, and carbon containing nitrogen are determined by input power, reaction pressure,
By changing discharge parameters such as the shape of the discharge vessel, the flow rate of the carbon raw material, and the flow rate of the raw material of halogen elements and nitrogen, it is possible to easily and inexpensively change the discharge parameters over a relatively wide range.

Furthermore, a film whose main component is carbon to which a halogen element and nitrogen or a halogen element, nitrogen, and hydrogen are added is characterized by low internal stress. This is because the dangling bonds that normally exist in carbon are terminated with hydrogen, which relieves the attractive force of the dangling bonds and reduces internal stress. However, some dangling bonds remain in the film, and this is thought to be one of the causes of internal stress.

When halogen elements and nitrogen, which are more reactive than hydrogen, such as fluorine and nitrogen, are present in the plasma, fluorine and nitrogen easily form C-F and C-N bonds with carbon, and the only dangling bond of carbon is hydrogen. This is considered to be lower than in the case of .

In other words, internal stress is reduced. Another feature is that the reduction in internal stress prevents the occurrence of peeling of the film.

Furthermore, a film whose main component is a halogen element and nitrogen, or carbon to which a halogen element, nitrogen, and hydrogen are added is also excellent in terms of heat resistance.

Another feature is that films whose main components are halogen elements and nitrogen, or carbon to which halogen elements, nitrogen, and hydrogen are added, can be formed at low deposition substrate temperatures ranging from room temperature to 150°C or less. be. Therefore, organic substances such as plastics and resins, selenium semiconductors, etc., can be used as the base of the composite.
It can also be constructed from materials that cannot be heated to high temperatures.

The production method will be described below according to the drawings.

FIG. 5 shows an outline of a plasma CVD apparatus used in the present invention for forming a film mainly composed of a halogen element and nitrogen or carbon to which a halogen element, nitrogen, and hydrogen are added.

In the drawing, in the doping system (1), hydrogen as a carrier gas is added as a carrier gas, a hydrocarbon gas as a reactive gas such as methane or ethylene is added as a doping system (3), and a gas containing a halogen element and nitrogen as an example as N F 3 is added as a reactive gas. and NHL (4
), the reaction system (8) passes through the valve (6) and flow meter (7).
It is introduced into the interior through a nozzle (9). Before reaching this nozzle, microwave energy is applied for excitation of the reactive gas (00).
It is effective to activate it in advance in addition to the above.

The reaction system (8) includes a first electrode OD and a second electrode (121
has been established. In this case, condition 1 (first electrode area/second electrode area) was satisfied. A pair of electrodes (11)
, 02), electric energy is applied from the high frequency power source 03), the matching transformer side, and the DC bias power source 051, and plasma is generated. The exhaust system 06) includes a pressure adjustment valve 07), a turbo molecular pump 00, and a rotary pump 0.
9) to exhaust unnecessary gas. Energy of 0.1 to 5 KW is applied to the reactive gas by high frequency or direct current energy at a pressure in the reaction space QO of 0.001 to 10 Torr, typically 0.01 to 1 TorrO.

In particular, when the excitation source has a frequency of IGH or higher, for example 2.45 GH2, hydrogen is separated from the C-H bond, and the frequency source is 0.1 to 50 MH2, for example 13.56 GH2.
At the frequency of , the C-C bond and C=C bond are decomposed,
-C-C- bonds are formed, and the unpaired bonds of carbon collide with each other to form a covalent bond, resulting in a structure locally having a stable diamond structure.

DC bias is -200 to 600V (substantially -4
00 to +400 V). This is because when the DC bias is zero, the self-bias has a voltage of 1200V (with the second electrode at the ground level).

As described above, fluorine and nitrogen or carbon containing fluorine, nitrogen, and hydrogen having an amorphous structure with a large number of C--C bonds formed on the surface to be formed or an amorphous structure having a microcrystalline structure was generated by plasma. Furthermore, this electromagnetic energy supplies 50W~1W and 0.0W per unit area.
3 to 3 w/c++] plasma energy was applied. As shown in FIG. 6, the transmittance of this carbon containing fluorine and nitrogen was 95% or more in the wavelength range of 600 nm or more, and an almost transparent film with 50% or more transmission was obtained even at 400n+n. Furthermore, the internal stress of the film was very small, at 1710 or less, compared to a film containing no fluorine or nitrogen. Even if the surface was immersed in chemicals such as acids, alkalis, and organic solvents for one hour at room temperature, no change was observed when observed under an optical microscope at 400x magnification. Although the film was left in (air) for 1 hour, no change was observed on the surface, and a chemically and thermally stable film could be obtained.

The above-described production method is just an example, and the well-known glow discharge plasma, arc discharge plasma, or plasma using ECR may be used.

Hereinafter, a composite to which the present invention is applied will be described in more detail according to Examples.

"Example 1" An example in which the composite according to the present invention is applied to a photoreceptor used in an electrophotographic process will be described below.

FIG. 7 shows the structure of a photoreceptor to which a coating mainly composed of carbon according to the present invention is applied. Approximately 200μm thick PE
AI vapor deposition layer (2) with a thickness of 600 people on the T-sheet (1),
A charge generation layer (4) with a thickness of 0.6 to 1.2 μm is provided between the intermediate layer (3), and a protective film (6) according to the present invention is formed with a thickness of about 20 μm.
When light (7) is incident through the charge transfer layer (5) of tIm, it is absorbed by the charge generation layer, and electron-hole pairs are generated. If the charge transfer layer or the protective layer is negatively charged in advance, holes generated in the charge generation layer move through the charge transfer layer only in areas where light is incident, neutralizing the negative charges. At this time, electrons generated in the charge generation layer pass through the intermediate layer, reach one deposited layer, and are discharged. The negative charge remaining in the area where no light was incident then adsorbs toner and is transferred to the transfer paper, forming an image on the transfer paper depending on whether or not light is incident.

The protective layer formed here uses the present invention,
Depending on the flow rate of NF3 and NH, the specific resistance is 1011~1
0' (0 cm). Therefore,
There is no lateral movement of charged charges that occurs because the resistivity is too low, and the boundaries of the area where light is incident are clear without blurring. Therefore, the transferred image was also clear. Furthermore, if the specific resistance is too high, charges will gradually accumulate in the protective film due to repeated use, making it impossible to remove used toner and causing the transfer paper to become black. Since the resistivity was controlled to such an extent that no accumulation occurred, it was possible to obtain high-quality transferred images over a long period of time without such a phenomenon.

Further, the transmittance of the protective film used here was 80% or more in a wavelength range of 500 nm or more, and 60% or more in a wavelength range of 400 nm or more. Therefore, the photoreceptor of this practical example was sufficiently usable even in the visible light range.

Of course, it goes without saying that durability against mechanical stress such as abrasion resistance and scratch resistance is improved.

Furthermore, the protective film used here had reduced internal stress and good adhesion. That is, even when the sheet-like photoreceptor was bent to a radius of curvature of 10 ma+, no cranking was observed in the protective film, and no beering occurred.

In this embodiment, a sheet-like organic photoreceptor has been described as a photoreceptor, but the protective film according to the present invention can be similarly constructed for a drum-shaped organic photoreceptor, an amorphous silicon photoreceptor, and a selenium photoreceptor. The effect of this can be obtained.

“Example 2j A typical thermal print head structure is shown in FIG.

A glaze (2) is formed on an insulating substrate (1), a protruding glaze (3) is formed on the part corresponding to the heating element at the same time as the glaze (2), and then a heating element (4) is formed on the substrate (]]). )
and an electric conductor (5) are sequentially laminated, and then a heating element portion (21) is formed on the protruding glaze using a known photolithography technique, and finally, fluorine and nitrogen or fluorine according to the present invention are laminated. A film mainly composed of carbon containing nitrogen and hydrogen was formed as a protective film (6).

The protective film usually used is an inorganic film such as a silicon nitride film.
Although the film thickness is as large as 5 μm, the protective film (6) used in this example has the same characteristics as the protective film formed in Example 1, and controls the flow rates of NF3 and NH3. As a result, a hard film with a Vickers hardness of 2000 kg/m+a" or more can be formed. Therefore, a film with a thickness of about 1 μm is sufficient for practical use.

Furthermore, the internal stress of the protective film used in this example was 109 dy.
It was confirmed that the adhesion was small (n/cm" or less) and had good adhesion, and that it was also good in a heat resistance test at 500°C for 1 hour (in air).

Further, a specific resistance of about 10''Ωcm is convenient for countermeasures against static electricity, and it is possible to reduce dirt and dust that can cause scratches, and also to reduce the influence of static electricity on electronic circuits.

In this application example, a known heating element (4) was used, but it is also possible to use a coating mainly composed of carbon containing a halogen element and nitrogen according to the present invention as the heating element. That is, if a film is formed under film-forming conditions such that the concentrations of the halogen element and nitrogen are high, and the resistivity of the film is set to 10 3 to 10 4 Ωcm, this film can be used as a heating element.

``Example 3'' In this example, a coating mainly composed of carbon according to the present invention was applied to a contact type image sensor, and a coating mainly composed of carbon having the structure shown in FIG. 9 was formed.

As shown in FIG. 9, electrodes and amorphous silicon are laminated on a transparent glass substrate (33) using a known plasma CVD method, and the electrodes and amorphous silicon layer are processed using an excimer laser to form a photosensor element (34). ) was formed, and then a transparent polyimide (35) was applied by a known spinner method to produce a contact image sensor. Thereafter, a protective film (
36) to 2. Ol! It was formed to a thickness of m.

The Vickers hardness of the protective film was measured and was 2500.
Kg/mm', and the specific resistance is lXl0'ΩcII
It was +. The formed carbon film has a hardness similar to that of diamond on the surface to be formed and a suitable electrical insulation property for static electricity countermeasures. There were no scratches, and even if static electricity was generated due to friction between the document and the protective film, it was possible to prevent static electricity from accumulating.Also, in addition to suppressing the electrical influence on the optical sensor element, the translucent polyimide It was possible to prevent impurities from entering the container.

"Effects" As described above, the present invention is a composite having a film mainly composed of a halogen element and nitrogen, or hydrogen, a halogen element, and carbon to which nitrogen is added. , the hardness of the coating can be easily and inexpensively adjusted,
Translucency and specific resistance can be changed, and in addition, the internal stress of the coating is small and the adhesion is good.

As described in the examples, in a composite to which a coating mainly composed of carbon to which a halogen element and nitrogen or hydrogen, a halogen element, and nitrogen are added according to the present invention, the coating mainly composed of carbon according to the present invention is applied. Compared to the case where this method did not work, the lifespan and reliability of the composite could be significantly improved.

[Brief explanation of the drawing]

FIG. 1 shows the relationship between the flow rate and conductivity of NF, and NH. FIG. 2 shows the relationship between the flow rate and permeability of NF and NH3. FIG. 3 shows the relationship between the flow rates of NF and NH3 and the hardness. FIG. 4 shows the relationship between input power and conductivity. FIG. 5 shows an outline of a plasma CVD apparatus for forming carbon or a film containing carbon as a main component according to the present invention. FIG. 6 shows the transmittance of carbon containing fluorine, nitrogen, and hydrogen. FIG. 7 shows the structure of a photoreceptor to which a coating mainly composed of carbon according to the present invention is applied. FIG. 8 shows a typical thermal print head structure. FIG. 9 shows a contact type image sensor to which the film containing carbon as a main component of the present invention is applied. /θjiλrishi0, ~'R+ /Vl'/3 Ureigo1 and (S here!
Go) Fig. 2 /l//”3 + N1-b flow back (sccFl) Ne I Tohachiq also ten people H3 U! L% (sccH) Name 3 figure input t Ka (w) Fig. 4 So ( Ugo (rlnsu No. 2

Claims (1)

[Claims] Carbon-based coatings created using plasma CVD (chemical vapor deposition) and actively added with halogen elements and nitrogen or hydrogen and halogen elements and nitrogen are used on glass, metals, ceramics, organic resins, etc. A composite having a film mainly composed of carbon, which is formed on a substrate.