JPH02208292A - Production of diamond film - Google Patents

Abstract

PURPOSE:To obtain a diamond film in improved profitability and reliability by changing raw material gases into a plasma jet with an arc discharge and allowing a diamond film synthesized from the raw gases to grow on the surface of a substrate in a chamber. CONSTITUTION:Raw material gases such as H2 and methane gases are fed from a gas-introducing opening 6a at the upper portion of a reaction chamber 4 and converted into a plasma jet 9 with an arc discharging 8. The plasma jet 9 is applied to a substrate in the chamber 4 to thermally melt the substrate and simultaneously form a diamond film on the surface of the melted liquid. When a substrate 1 such as gallium having a melting point of 30 deg.C and a boiling point of 2400 deg.C is employed, the substrate is thermally melted with the plasma jet 9 but does not evaporate even at 1000 deg.C used for synthesizing the diamond film 2, thereby stably allowing the diamond film to grow on the surface of the melted substrate. Thus, a 0.5mm thick diamond film is synthesized on the surface of the substrate 1 in the growing process of approximately 5hr.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for producing a diamond film synthesized from raw material gas by CVD method, production of a diamond film capable of synthesizing a thick diamond film by a simple and easily performed process. The purpose of the present invention is to provide a method for producing a diamond film using a CVD method, in which a raw material gas is turned into a plasma jet by arc discharge, and a diamond film synthesized from the raw material gas is melted in a container with a low melting point and a low melting point. It is configured to grow on the surface of a substrate made of a material with a high boiling point.

[Industrial application field]

The present invention relates to a method for producing a diamond film synthesized from a raw material gas by a CVD method.

Diamond is used as a high-performance cutting tool due to its high hardness, and it also has a high thermal conductivity several times that of copper, so it is used in active devices that generate a large amount of heat, such as laser diodes. It is used as a heat sink for cooling.

However, when manufacturing a thick diamond film, the temperature of the substrate during diamond synthesis is
Since the thermal expansion coefficients of the substrate and diamond are different, the stress increases as the film thickness increases, and peeling occurs during the film formation process. Have difficulty.

Under the above circumstances, there is a need for a diamond film manufacturing method that can produce a thick diamond film.

[Conventional technology]

In the conventional diamond film manufacturing process, the substrate temperature is over 1,000°C and the thermal expansion coefficients of the substrate and diamond are different. This stress acts during the process and increases as the thickness of the film increases.
It has been difficult to produce thick diamond films.

There was a problem in that it was difficult to manufacture a thick Diamond I film.

In view of the above-mentioned circumstances, the present invention aims to provide a method for manufacturing a diamond film that can synthesize a thick diamond film by a simple and easy process.

[Means for Solving the Problems] The method for producing a diamond film of the present invention is a method for producing a diamond film by the CVD method, in which a raw material gas is converted into a plasma jet by AC discharge, and a diamond film is synthesized from this raw material gas. A diamond film is configured to grow on a substrate made of a low melting point, high boiling point material that is molten in a container.

[Problem to be solved by the invention]

In the conventional diamond film manufacturing method described above, the substrate temperature is high and the thermal expansion coefficients of the substrate and diamond are different, so it is difficult to remove the diamond film from the substrate! In other words, in the present invention, hydrogen scum and methane gas are converted into plasma dieso I by arc discharge, and the substrate +A $'4, which has a low melting point and a high boiling point, is placed in a container. Since the diamond film is grown using the CV l) method by injecting a plasma jet onto the surface of the diamond film, the gap between the diamond film and the substrate is maintained both during the growth of the diamond film and even when the temperature decreases after growth. Since no stress is applied to
It becomes possible to manufacture a thick diamond film.

〔Example〕

An embodiment of the present invention using gallium as the substrate material will be described below with reference to FIG.

First, a diamond film 2 is formed on the surface of a substrate 1 made of gallium placed in a container 3 using a CVD apparatus as shown in FIG. 1 under the following conditions.

Introduced gas and gas flow rate --- Hydrogen gas (H) 10 to 5012/min and methane gas (CH4,) 0.5 to 1.02/min DC power supply voltage --- −1−−−−−−−−−−−
-----------50~15V arc current------
−−−−〜−−−−−−−−−−−−−−10 to 70
A reaction chamber pressure------, 1,000 to 10,00
0 pass power Figure 1 is a schematic structural diagram of the CVD apparatus, in which the lower part of the reaction chamber 4 is cooled, the chamber pressure being maintained at the above reaction chamber pressure by the exhaust device 1 connected to the exhaust port 10. Stage 5 where water is supplied from the cooling water supply port 5a
A container 3 with a substrate 1 placed therein is placed therein, and an electrode 6 equipped with a gas conductor 6a is provided in the upper part of the reaction chamber 4, and this electrode 6 is connected to a DC power supply. A voltage is applied by 7, and a plasma jet 9 is generated by the AC discharge 8.
occurs.

Hydrogen gas and methane gas are supplied from the gas inlet 6a, so when the plasma jet 9 hits the substrate 1, the substrate 1 becomes high temperature and melts, and a diamond film 2 grows on the surface of the molten liquid. .

The substrate 1 is made of gallium, which has a melting point of 30'C and a boiling point of 2.0C.
Since the temperature is 400°C, it is heated and melted by the plasma jet 9, and the diamond film synthesis temperature is 1,000°C.
It becomes possible to stably grow the diamond film 2 on the surface without evaporating even if the temperature reaches °C.

In this way, a thickness of 0.5 mm was obtained during the 5-hour growth process.
It becomes possible to synthesize the diamond film 2 on the surface of the substrate 1 without peeling it off.

Furthermore, even when the growth of the diamond film 2 is restarted after the growth of the diamond film 2 is interrupted, the substrate 1 becomes liquid and has good contact with the diamond film 2 that has already been synthesized, so that the diamond film 2 continues to be stable. This made it possible for the company to continue its growth.

[Effects of the Invention] As is clear from the above description, according to the present invention, raw *S
4 gas is turned into a plasma jet, and the diamond film synthesized from this raw material gas can be grown on the surface of a substrate made of a material with a low melting point and a high boiling point that is melted in a container, making it extremely economical. Furthermore, it is possible to provide a method for manufacturing a diamond film that can be expected to have the effect of improving reliability.

It is.

In the figure, 1 is the board, 2. Diamond film, 3ba container, 4 is a reaction chamber; 5ba stage, 5a is a cooling water supply port; 6 is an electrode, 6a is a gas inlet; 7 is a DC power supply, 8 arc discharge, 9 is plasma geso 1-1 10 is an exhaust port, 11 is an exhaust system, shows.

[Brief explanation of the drawing]

Claims (1)

[Claims] A method for producing a diamond film by the CVD method, which comprises converting raw material gas into a plasma jet (8) using an arc discharge (8).
9), and the diamond film (2) synthesized from the raw material gas is grown on the surface of the substrate (1) made of a material with a low melting point and a high boiling point, which is melted in the container (3). A method for producing a diamond film.