JP2673766B2 - Method for manufacturing carbon-based material - Google Patents

Description

Description: The present invention is based on carbon or carbon having an energy band width of 2.0 eV or more, similar to diamond, which has the highest thermal conductivity in solids and the most abrasion resistance. The purpose is to form a carbon coating with the material. [0002] The present invention relates to a plasma-enhanced gas-phase process such as amorphous (semi-amorphous, hereinafter referred to as AS) or semi-amorphous (semi-amorphous, hereinafter referred to as SAS) having a crystallinity of 5 to 20 ° At a low temperature of 100 to 450 ° C, preferably 200 to 350 ° C. The purpose is to provide the carbon coating on silicon. [0003] As a result, a film similar to diamond having an energy band width of 2.0 eV or more and having poor adhesion to carbon or a film containing carbon as a main component can be applied to a film containing carbon or carbon as a main component. It can be applied. According to the present invention, such a film is formed by a plasma gas phase method, that is, a DC high frequency of 500 KHz to 50 MHz under a reduced pressure of 0.01 to 10 torr.
z) or by applying electromagnetic energy of microwaves (for example, a frequency of 2.45 GHz) or generating an arc discharge to form a plasma, and the reactive gas vaporized by such electromagnetic energy, for example, a hydrocarbon gas such as ethylene or propane; By activating and decomposing, the main component is carbon or carbon having an energy bandwidth of 2.0 eV or more similar to that of diamond containing 30 mol% or less of hydrogen or silicon in insulating carbon or carbon of AS or SAS. Is formed. The energy band width of the carbon formed by the plasma gas phase method is 2.0 eV or more, typically 2.5 to
It is an insulator having 3 eV and its thermal conductivity is 2.5 or more typically 5.0 (W / cm deg) and 6.60 (W / cm
deg). Further, the Vickers hardness of 4500 kg / mm ² or more, typically 6500 kg / mm ² , which is extremely excellent in diamond-like hardness is found. , And has high-speed heat-sensitive response. Further, the present invention provides such an AS or SAS 450
When boron or phosphorus, which is a trivalent or pentavalent impurity, is added to a concentration of 0.1 to 3 mol% in a carbon coating formed at a temperature of not more than 10 ° C., an electric conductivity of 10 ⁻² to 10 ⁻⁶ (Ωcm) ⁻¹ is obtained. Can be given. Therefore, in this case, it has another characteristic that it can be used as a heating element, and can have characteristics such as not necessarily forming a wear-resistant layer due to its mechanical characteristics. In the present invention, since the wear-resistant layer is formed by the plasma vapor deposition method under reduced pressure, the side portion of the heat generating layer can be protected with the same thickness as the upper surface. Therefore, in the case where it has been made by a sputtering method, a normal pressure gas phase method, or the like, the wear-resistant layer is covered with a thickness of 2 μm or more (0.2 μm or more in side thickness) as a result to cover this side surface.
Needed. However, in the present invention, since the upper surface and the side surfaces can be formed to have substantially the same thickness, the upper surface has a thickness of 0.1 to 0.3.
μm is sufficient, and as a result, the thickness is reduced to about 1/10, so that the response speed of heat sensitivity can be further improved. In the present invention, the reactive gas is a hydrocarbon such as acetylene (C ₂ H ₂ ) or a methane-based hydrocarbon (C _n H _{2n + 2} ).
Gas or silicon partially contained, tetramethylsilane ((CH ₂ ) ₄ Si), tetraethylsilane ((C ₂ H ₅ ) ₄ Si
) May be used. In the former, hydrogen is 30 in carbon
Although it was present in an amount of 0.01 to 5% by mole, particularly when SAS was defined as 0.01 to 5% by mole, covalent bonds between carbon atoms were strong and had properties similar to diamond. In the latter, hydrogen is 0.01 ~
Insulating material containing 20 mol% and further containing 1/3 to 1/4 of carbon, so-called carbon-excess silicon carbide, and having carbon as a main component (optical energy bandwidth Eg> 2.0 eV typically Was 2.5 to 3.0 eV). An embodiment will be described below with reference to the drawings. EXAMPLE In this example, a thermal head is used as an application of the present invention. FIG. 1 is a vertical sectional view of a thermal head printer used in the present invention. FIG. 1B is a sectional view taken along line AA ′ of FIG. 1A.
(C) shows a cross-sectional view of BB ′. In the drawing, a glass layer (2), a heating element layer (3), and an electrode (4) which are glazed on a substrate, particularly a ceramic substrate.
And a wear-resistant layer (5). Also the first
As shown in FIG. (C), the portion where the thermal paper is rubbed is the heating layer
(3) A wear-resistant layer (5) is provided in contact with the upper part. In the present invention, since the wear-resistant layer (5) is made of carbon or a material containing carbon as a main component and this material is formed by a plasma vapor phase method, as shown in FIGS. 1 (B) and 1 (C). The feature is that the thickness of the side portion of the heating element layer can substantially match the thickness on the heating element layer. This is because the pressure is under reduced pressure (0.01 to 10 torr), the mean free path of the reactive gas becomes long, and when the gas phase method is carried out, the wraparound to the side is large. In addition, the reaction gas is turned into plasma, giving a large kinetic energy to the reactive gases and causing them to collide with each other, thereby promoting flight in all directions. The wear-resistant layer was prepared as follows. That is, a substrate having a surface to be formed is sealed in a reaction vessel, the reaction vessel is evacuated to 10 ^-3 torr, and the substrate is heated to 100 to 450 ° C, preferably 200 to 350 ° C, for example, 300 ° C by a heating furnace. Heated. Thereafter, hydrogen and helium were introduced into the atmosphere, and the pressure was adjusted to 10 ^-2 to 10 torr, and then electromagnetic energy was applied by an induction method or a capacitive coupling method. For example, the frequency of the applied electric energy is 13.56MHZ
z, the output is 50-500 W, and the actual electrode gap is 15
~ 150 cm long. This is because carbon, which is a reactive gas when it is turned into plasma, is an extremely stable material, and gives high energy to each element or an associated molecule in which carbon is associated, thereby causing carbon to form a covalent bond with each other. When the power applied to the formed film is 50-150 W, the AS
When 250 to 500 W was applied, SAS was observed, and in the middle, a mixed structure was observed by electron diffraction. Further, with respect to the plasma atmosphere,
A carbide gas such as methane or propane was introduced. Then, the reactive gas was dehydrogenated, and the bonds of carbon were covalently bonded to each other, so that a carbon film could be formed on the formation surface. When the temperature of the substrate is 100 to 200 ° C, the hardness is slightly low and the adhesion to the substrate is not always preferable. However, when the temperature is 200 ° C or more, especially at 250 to 350 ° C, an extremely stable strong surface is formed. Had adhesion to the surface. If the heat treatment is performed at 450 ° C. or higher, there is a problem that stress is inherent due to a difference in thermal expansion coefficient with the substrate, and a film formed at 250 to 450 ° C. is an ideal wear-resistant material. . The starting materials are TMS ((CH ₂ ) ₄ Si), TES ((C ₂ H ₆ ) ₄ S
When i) was used, the formed film was a film containing carbon containing 15 to 30 atomic% of silicon as a main component. This had the same hardness as carbon alone. The thermal conductivity of carbon alone was 5 W / cm deg, but was as low as 2-3 W / cm deg. The carbon film formed as described above has a thickness of 0.1 mm.
05 to 0.2 even thickness or thinness of the conventional 1/5 to 1/10 of μm had a wear resistance to withstand the use of 10 ⁵ hours. [Embodiment 2] In this embodiment, a thermal head having the same hardness as that of the embodiment 1 is formed by using the same plasma vapor phase method as that of the embodiment 1 to form a heating element layer. The production was performed by the plasma gas phase method under the same conditions as in Example 1. However, since the formed film needs to be conductive (resistive) or semiconductive, the formed film is doped with trivalent or pentavalent impurities such as boron or phosphorus, for example, impurity gas / silicide gas = A silicon film of AS or SAS added to 0.01% or less or a film mainly composed of resistive or semiconducting carbon in which such impurities are added to impurity gas / carbide gas = 0.01 to 3% were formed. That is, for the former silicon film, silane (SinH _{2n + 2} n ≧ 1) silicon tetrafluoride is used as a starting material,
It was formed at a similar temperature of 100 to 450 ° C, for example, 200 to 350 ° C.
The high frequency energy was 13.56 MHz at 10 to 50 W, AS, or 50 to 200 W to form SAS. The trivalent impurity was, for example, boron using B ₂ H _6, and the pentavalent impurity was, for example, phosphorus using PH ₃ , with a small doping or non-doping as in the ratio described above. Hydrogen in the formed film
Although the content was 20 mol% or less, they were released to the outside by heat generation. The same acetylene as in Example 1 was used for carbon. Where B ₂ H ₆ / C ₂ H ₂ = 0.01-3%, PH
₃ / C ₂ H ₂ = was formed as a 0.01 to 3%. As a result, the electric conductivity of the formed film was 10 ⁻⁸ to 10 ⁻⁴ (Ωcm) ⁻¹ . As is apparent from the above description, the present invention uses the plasma vapor phase method as a basic idea, and thus the conventional film forming method in which the substrate temperature is 100 to 450 ° C., typically 250 to 400 ° C., and particularly 300 ° C. It is possible at low temperatures if you think about. Particularly, when the temperature is 500 ° C. or less, when glass is used as a substrate material, the distortion of thermal expansion is extremely reduced, and a large defect such as substrate warpage due to conventional high-temperature processing can be prevented. As a result, only six heat-generating parts of a conventional thermal printer could be made per mm.
This can be increased to 24. As is apparent from the above description, the present invention uses insulating light-transmitting carbon having an energy band width of 2.0 eV or more and typically 2.5 to 3 eV as a wear-resistant material, and further comprises carbon or carbon. It is characterized in that a resistor or a semiconductor containing carbon as a main component is used as a heating element layer. For this purpose, the present invention forms one or both of them by a plasma gas phase method, and can be made at a temperature of 500 ° C. or less, which is 300 to 500 ° C. lower than the temperature formed by the conventional gas phase method, and selects a substrate material. It had a great degree of freedom and was very excellent in reducing the price. When the method of the present invention is applied to a thermal head, the thickness of the top surface and the side surface of the heating element layer of the thermal head can be formed to be almost the same thickness. If the thickness is more than the required amount, the thick portion does not become ten times thicker. When the top and side surfaces are covered, the effect of increasing the adhesion between the substrate and the heating element layer is obtained. The present invention has mainly described the plasma gas phase method. However, as long as such abrasion resistance can be obtained, electromagnetic energy or light energy such as ion plating or other plasma or laser may be used. The structure shown in FIG. 1 in the embodiment of the present invention is an example of the structure of the present invention. The heating element layer may be a single crystal and may have a transistor structure, and may be used for a silicon mesa structure, a planar structure or the like. Can be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a thermal printer of the present invention.

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Claims (1)

(57) [Claims] Electromagnetic energy or light energy is applied to a compound gas in which a part of hydrocarbons is replaced with silicon and hydrogen to dehydrogenate the carbon to have a covalent bond between carbons, and to reduce carbon containing 30 mol% or less of silicon. A method for producing a material containing carbon as a main component, which is characterized by being produced. 2. Electromagnetic energy or light energy is applied to a compound gas obtained by substituting a part of hydrocarbons with silicon and hydrogen to dehydrogenate the carbon to have a covalent bond between carbons, and hydrogen is added to 0.01
A method for producing a material containing carbon as a main component, which comprises producing silicon carbide containing carbon in excess of 20 mol%.