JPH05132394A - Synthesis of diamond film by vapor-phase process - Google Patents

Abstract

PURPOSE:To effect the uniform growth of a diamond thin film on a substrate in high density and high deposition strength at a high speed by coating the surface of a substrate with an ester solution containing fine particles of a carbonaceous material, heating the coated substrate and supplying a raw material for the synthesis of diamond. CONSTITUTION:In a process for depositing a diamond film on a substrate by a vapor-process, the surface of the substrate is coated with an ester solution containing carbon black or soot, the substrate is heated at 100-600 deg.C and a gaseous raw material is supplied to the substrate. When a vapor-phase synthetic reaction of diamond is carried out by using the above gas, the deposition probability of the diamond precursor radical to the carbon compound particle is increased to facilitate the formation of diamond nucleus. Further, the nucleus formation density is also increased to increase the deposition strength of the formed diamond to the substrate and the film thickness becomes extremely uniform. The amount of the fine particles of the carbonaceous material in the ester solution is preferably 1mg to 0.3g based on 100cc of the ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for synthesizing a film-like diamond by a vapor phase method, and more particularly to a method for increasing the density of diamond nucleation on a substrate, thereby easily forming a film-like diamond of uniform thickness. Regarding processing method.

[0002]

2. Description of the Related Art In the synthesis of vapor phase diamond, it is necessary to generate more nuclei in order to control the shape and homogeneity of diamond. In the growth of diamond in the vapor phase method, first, fine diamond nuclei are generated at singular points on the substrate, and then the nuclei grow three-dimensionally, and then adjacent crystal grains coalesce into a film shape. become. Therefore, if the nucleation density is too low, film growth does not occur. As a method of increasing the density of diamond nuclei generation, scratch treatment with diamond powder etc. (The 48th Annual Meeting of the Applied Physics Society of Japan,
18a-T-5) has been proposed. Also, the nucleation density,
As a method for increasing the adhesion strength between the diamond film and the substrate interface, etching with chemicals such as acids and alkalis (The 48th Applied Physics Society Academic Meeting, 18a-T-
4), etching in a specific gas containing alcohol or the like (JP-A-1-145396) is known. However, the maximum nucleation density is 10 ⁷ /
It is on the order of cm ² .

The present inventors have conducted research for the purpose of developing a method for increasing the nucleation density, and have confirmed that carbon black or graphite particles are excellent as nucleating agents, and found that Japanese Patent Application No. 3388 (Japanese Patent Laid-Open No. 2-1845
97) was filed. However, this method is suitable for producing diamond grains, but when the purpose is to produce a diamond film, the uniformity of the film is insufficient and it is not suitable for producing a diamond film.

[0004]

Accordingly, the conditions for synthesizing a practically useful homogeneous diamond, that is, the development of a method in which a diamond thin film is uniformly grown at a high density and a high adhesion strength on a substrate. Is strongly demanded.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted research to meet the above-mentioned demands, and as a result, a treatment agent comprising carbonaceous fine particles and an ester solvent was applied to the substrate, and the heat-treated substrate was used. Knowing that by doing so,
The present invention has been completed. That is, according to the present invention, the ester solution containing carbonaceous fine particles is applied to the surface of the substrate, and then the substrate is heated to 100 ° C.
The present invention relates to a method for synthesizing a film-shaped diamond by a vapor phase method, characterized in that a raw material gas for synthesizing diamond is supplied after being heated to 600 ° C.

The carbon black or soot of the present invention has a maximum particle size of 0.1 μm, preferably 0.005 to 0.07 μm.
Is. Although the heating time is not particularly limited, it is practically 1 to several hours. Specifically, the ester solvent and the carbonaceous fine particles are bonded by heating, and dispersed and scattered as carbon compound particles on the substrate.

When the gas phase diamond synthesis reaction is carried out using such a gas, the probability of the diamond precursor radicals adhering to the carbon compound grains is increased, the formation of diamond nuclei is facilitated, and the nucleation density is increased by the conventional method. In comparison with the above, the adhesion strength of the produced diamond to the substrate becomes large, and the film thickness becomes extremely uniform.

Acetate is specifically used as the ester solution, and a commercially available marker is particularly practically preferable. The amount of carbonaceous particles in the ester solution is 1
The range of 1 mg to 0.3 g in 00 cc is preferable.

[0009]

EFFECTS OF THE INVENTION It is possible to form a uniform diamond film by the vapor phase method.

[0010]

【Example】

Examples and Comparative Examples Next, the present invention will be described with reference to Examples and Comparative Examples. Example A carbon black particle size of 0.01 to 0.05 μm is 100
An ester solution containing 10 mg in cc (actually a commercially available white plate marker) was uniformly applied to the surface of a 25 mm square silicon wafer. This silicon wafer was heated at 250 ° C. for 2 hours using a normal hot filament method diamond synthesizer (diameter: 25).
cmφ × height 20 cm), 90 torr, H ₂
The treatment was performed in an atmosphere of 100 cc / min and ethanol 3 cc / min. The distance between the silicon wafer substrate and the hot filament was set to 5 mm, gasified ethanol was introduced at 3 cc / min and hydrogen was introduced at 100 cc / min into the reaction furnace at a pressure of 90 torr for 2 hours to deposit diamond. The reaction continued. Diamond particles of 0.5 μm on average are deposited in high density on the substrate to form a film. The diamond was confirmed by an optical microscope and Raman spectroscopy. The diamond nucleus generation density was determined from the value calculated from the SEM photograph 5 minutes after the start of synthesis. The result was 5 × 10 ⁹ / cm ² .
Further, FIG. 1 is a SEM photograph (magnification: 200
Times).

Comparative Example 1 Diamond synthesis was performed under the same conditions except that the ester solution was not applied to the silicon wafer and the heat treatment was not performed. After the synthesis, 5 to 8 μm particles were scattered on the substrate.
Incidentally, FIG. 2 shows SEM 2 hours after the start of synthesis (magnification: 200 times).
Is. Nucleation density is about 10 ³ / cm ² to 10 ⁴ / cm
^{Was 2} . Comparative Example 2 A graphite electrode was ground with sandpaper, the obtained powder having a diameter of submicron to several μm was dispersed in ethanol, and the same was applied on the surface of a silicon wafer as in the examples. The diamond synthesis reaction was performed under the same conditions as in the examples. As a result of observing on the silicon wafer after completion of the reaction, it was confirmed that a small amount of diamond automorphism was mixed in the roundish aggregate of diamond-like carbon in a non-uniformly dispersed state. The nucleus generation density is 10 ¹ / cm ² to 10 ³ / c.
It was m ² .

[Brief description of drawings]

FIG. 1 is 200 times S 2 hours after the start of synthesis in Examples.
It is an EM micrograph.

FIG. 2 is a 200 × SEM micrograph taken 2 hours after the start of synthesis in Comparative Example 1.

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[Procedure amendment]

[Submission date] October 26, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a 200 × SEM micrograph of a deposited diamond thin film 2 hours after the start of synthesis in an example.

FIG. 2 is a 200 × SEM micrograph showing the grain structure of precipitated diamond 2 hours after the start of synthesis in Comparative Example 1. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 13, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

EXAMPLES [Examples and Comparative Examples] Next, the present invention will be described with reference to Examples and Comparative Examples. Example A carbon black particle size of 0.01 to 0.05 μm is 100
An ester solution containing 10 mg in cc (actually a commercially available white plate marker) was uniformly applied to the surface of a 25 mm square silicon wafer. This silicon wafer was heated at 250 ° C. for 2 hours using a normal hot filament method diamond synthesizer (diameter: 25).
cmφ × height 20 cm), 90 torr, H ₂
The treatment was performed in an atmosphere of 100 cc / min and ethanol 3 cc / min. The distance between the silicon wafer substrate and the hot filament was set to 5 mm, gasified ethanol was introduced at 3 cc / min and hydrogen was introduced at 100 cc / min into the reaction furnace at a pressure of 90 torr for 2 hours to deposit diamond. The reaction continued. Diamond particles of 0.5 μm on average are deposited in high density on the substrate to form a film. The diamond was confirmed by an optical microscope and Raman spectroscopy. The diamond nucleus generation density is S of the diamond which is 5 minutes after the start of synthesis.
It was determined from the value calculated from the EM photograph. The result is 5 × 10 ^3.
Was / cm ² . In addition, FIG. 1 is an SEM photograph (magnification: 200) of the deposited diamond formed into a film 2 hours after the start of synthesis.
Times).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

Comparative Example 1 Diamond synthesis was performed under the same conditions except that the ester solution was not applied to the silicon wafer and the heat treatment was not performed. After the synthesis, 5 to 8 μm particles were scattered on the substrate.
Note that FIG. 2 is an SEM (magnification: 200 times) of particulate precipitated diamond 2 hours after the start of synthesis. Nucleation density is about 1
It was 0 ³ / cm ² to 10 ⁴ / cm ² . Comparative Example 2 A graphite electrode was ground with sandpaper, the obtained powder with a diameter of submicron to several μm was dispersed in ethanol, and the same was applied on the surface of a silicon wafer as in the example. The diamond synthesis reaction was performed under the same conditions as in the examples. As a result of observing on the silicon wafer after the completion of the reaction, it was confirmed that a small amount of diamond automorphism was mixed in the lump-shaped aggregate of diamond-like carbon, which was inhomogeneously dispersed. The nucleus generation density is 10 ¹ / cm ² to 10 ³ / c.
It was m ² .

Claims (1)

[Claims] 1. A method of depositing film diamond on a substrate by a vapor phase method, wherein an ester solution containing carbon black or soot is applied to the surface of the substrate, and then the substrate is heated at 100 ° C. to 600 ° C. A method for synthesizing membranous diamond by a vapor phase method, which comprises supplying hydrogen.