JPH01100093A - Production of diamond thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a diamond thin film by a hot filament CVD method among vapor phase synthesis methods.

[Prior art]

Conventionally, diamond thin films have been produced by vapor phase synthesis.
The gas phase synthesis method is roughly divided into the following three types. In other words, ■Chemical vapor phase synthesis method (CVD method)...
Pyrolysis CVD method, hot filament CVD method, ■Plasma CVD method...RF plasma CVD method, microwave C
These methods include the VD method and the ion beam evaporation method.

However, in these conventional vapor phase synthesis methods, in order to form a diamond film with good crystallinity, it is necessary to raise the substrate temperature to a high temperature of 700°C or higher, and if the substrate temperature is lower than that, amorphous diamond-like carbon This method has the problem of forming a diamond film, and even if a diamond thin film is formed, the deposition rate is slow.

On the other hand, diamond thin films can be used in semiconductors and electronic devices,
For example, when applied to high-temperature operation transistors, semiconductor lasers, high-power devices, etc., it is essential to form the film at a relatively low temperature of at least 600° C. or lower.

〔the purpose〕

An object of the present invention is to provide a method that can be applied to the semiconductor and electronic device fields and can produce a diamond thin film with excellent crystallinity at a relatively low temperature and at a high deposition rate.

〔composition〕

The inventors of the present invention have conducted intensive research to achieve the above-mentioned problems, and as a result have found that 1. Low-temperature film formation is possible by irradiating the substrate surface with inert charged energy particles.

Furthermore, the present invention was completed based on the knowledge that the deposition rate was significantly increased.

The present invention will be explained in more detail with reference to Examples below.

FIG. 1 shows an example of an apparatus used to carry out the present invention. In FIG. 1, 1 is a chamber, a susceptor 2 is provided in the chamber 1, and a substrate 3 is placed on it. The substrate 3 is heated by heat supply from the susceptor 2, and is heated to 250 to 85 G'C during the reaction.
1 Preferably, the temperature is maintained at 300 to 700°C. Therefore,
As the substrate 3, not only metal plates such as W, Mo, Ta, etc. but also S
The 0M material gas, which can be used for inorganic materials such as i-wafer, SiC, and quartz glass, is inserted from above the chamber 1 and supplied from a gas introduction tube 6 that opens above the substrate 3. The heating element 4 (thermal filament) disposed between the part and the substrate 3 thermally decomposes the activated species, and active species effective for film formation are generated. As the raw material gas, a mixed gas of hydrogen gas and at least one of hydrocarbon gas or organic compound gas containing CH or groups is used. Specifically, hydrocarbon gases include methane, ethane, propane,
It may be a saturated hydrocarbon such as butane, an unsaturated hydrocarbon such as ethylene, propylene, acetylene, butadiene, or an aromatic hydrocarbon such as cyclopropane, cyclohexadi, cyclobutadiene, benzene, toluene, etc. The organic compound gas may be any of alcohols such as methyl alcohol, ethyl alcohol, and isopropanol, ketones such as acetone, and ethers such as isopropyl ether and diethyl ether. Two or more of these carbon compounds may be used. It may be used in combination, and the mixing ratio of this carbon compound and hydrogen gas is such that the value of carbon compound gas/carbon compound gas in hydrogen gas is 0.1 to 10. Preferably it is in the range of 0.5 to 5. Hydrogen gas in such a raw material gas generates atomic H through thermal decomposition, and active species such as CH3 radicals, CH
It is thought that this serves to assist the movement of 3 ions on the surface of the substrate 3. As the heating element 4, a wire or boat of a metal heating element such as W, Mo, Ta, Kanthal, etc., or a rond of a lamic heating element such as 5iC1C can be suitably used, and the temperature is usually 1800 to 2300°C, preferably 19
It is heated to about 00 to 2100°C. In addition, the ion source 5
From there, charged energy particles consisting of an inert gas force 1 such as Ar, N, He, etc. are irradiated toward the substrate 3 with an energy of several tens to several thousand eV and an amount of several tens to several hundred mA/aj. irradiated.

In such a device, the inside of the chamber 1 is 10-3~
lO-”T o r r, and the raw material gas is several tens to several hundred 8
When a film is formed by CCM flow, the temperature of the substrate 3 must be at least 850°C or higher in order to obtain a high-quality diamond thin film without irradiation with charged energy particles from an ion source. When energetic particle irradiation was performed, a diamond thin film with good crystallinity was obtained even at a substrate temperature of 250 to 850°C, preferably 300 to 700°C. Moreover, when irradiation with charged energy particles is performed, the deposition rate of the diamond thin film is 150 ~
It showed a relatively large value of 400 people/min. The Raman spectrum and electron diffraction results of the obtained thin film were
It is shown in the figure and Table 1.

(The following is a blank space) Table 1 From the results shown in FIG. 2 and Table 1, it can be seen that the thin film obtained by the present invention is a diamond thin film having almost the same structure as natural diamond.

In the present invention, the reason for low-temperature film formation and improvement in deposition rate by irradiation with charged energy particles from an ion source is that the irradiated charged energy particles collide with active species on the substrate surface, increasing the excited state of the active species. This seems to be because it also energetically excites the substrate surface (reaction surface) and promotes the migration of active species on the surface.

〔effect〕

According to the present invention as described above, a diamond thin film with good crystallinity can be formed at a low temperature, making it possible to apply diamond thin films to semiconductors and electronic devices.Moreover, it is possible to deposit at high speed, and to improve efficiency. This has the effect of making it possible to form a good diamond thin film.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of an apparatus for carrying out the present invention. Figure 2 is a Raman spectrum diagram of the thin film obtained according to the present invention.

Claims (1)

[Claims] 1. When depositing a diamond thin film on the substrate by decomposing the source gas with a heating element placed near the substrate in a vacuum container, irradiating the surface of the substrate with charged energy particles. A method for producing a diamond thin film characterized by: