JP3229428B2 - Method for forming diamond generating nuclei - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a diamond generating nucleus, and more particularly, to a method for synthesizing diamond suitable for tools, semiconductors, coating members and the like on a surface of a substrate easily and simply. The present invention relates to a method for forming a diamond generating nucleus, which can form a diamond generating nucleus at a high density with high reproducibility and can improve the productivity of diamond.

[0002]

2. Description of the Related Art Diamond has extremely high hardness and excellent electrical properties, and is therefore useful as an industrial material useful in various fields including electronic and electric equipment. Attention has been paid.

Recently, a method of forming such a diamond on the surface of a substrate by a vapor phase method has been developed. In this case, if a nucleus for diamond synthesis (hereinafter referred to as a diamond generating nucleus) is formed on the surface of the substrate, the diamond generation rate increases. Therefore, in order to synthesize diamond efficiently, it is necessary to form diamond generating nuclei on the surface of the substrate in advance by various methods at a density as high as possible. For example, Japanese Patent Publication No. Sho 62-27039 discloses that diamond generating nuclei are formed on a surface of a substrate at a high density of 10 ⁶ to 10 ⁸ / cm ² by colliding diamond abrasive grains with the substrate. It is disclosed that when diamond is synthesized by a gas phase method, diamond can be synthesized efficiently.

[0004] However, in order to produce diamond efficiently, the density of diamond generating nuclei is not sufficient to the extent described in the above publication, and it is necessary to form diamond generating nuclei at a higher density. However, a method that can form diamond generating nuclei with high density is
It is not yet provided.

The inventors of the present invention have conducted intensive studies and as a result, when diamond particles containing a specific metal in a specific ratio are used to form a diamond generating nucleus,
It has been found that diamond generation nuclei can be formed at a high density.

The present invention has been made based on such knowledge by the inventor of the present invention, and includes tools, semiconductors,
On a surface of a substrate for synthesizing a diamond suitable for a coating member or the like, a diamond generating nucleus can be easily and simply formed at a high density with high reproducibility, and the productivity of diamond can be improved. An object of the present invention is to provide a method for forming a diamond generating nucleus.

[0007]

According to a first aspect of the present invention, there is provided a semiconductor device comprising:
3. A method for forming a diamond generating nucleus, comprising performing a scratching treatment using diamond particles containing at least one selected from the group consisting of o, Ni and Mn in a total amount of 200 ppm or more. The invention is characterized in that the diamond particles include at least one selected from the group consisting of Fe, Co, Ni and Mn in a total of 500 p.
2. The method according to claim 1, wherein the particles are diamond particles containing not less than pm.
The method for forming a diamond generating nucleus according to the above.

Hereinafter, a method of forming a diamond generating nucleus according to the present invention will be described in detail.

(Scratch treatment) In the method of the present invention,
A diamond generating nucleus is formed on the surface of the substrate by performing a scratching process using specific diamond particles.

The substrate is not particularly limited in its material and the like. For example, Si, gallium-arsenic, SiC,
SiO _2, Si ₃ N _4, alumina, AlN, WC-C
o, TaC, ceramics, sapphire, cemented carbide, M
A substrate formed from o, W, Ta, or the like can be given. Among them, Si, SiC, SiO ₂ and a cemented carbide are preferable. In the present invention, a silicon wafer can be particularly preferably used as the substrate. Further, the substrate may be a P-type or N-type semiconductor. The specific resistance of the substrate is usually 10 ⁻⁶ to 10 ³
Ω · cm.

The diamond particles include Fe, C
One or more selected from the group consisting of o, Ni and Mn are usually added in a total of 200 ppm or more, preferably 50
Diamond particles containing 0 ppm or more, more preferably 500 ppm to 5% by weight in total can be mentioned. If the content of at least one selected from the group consisting of Fe, Co, Ni and Mn is lower than 100 ppm in total, it is not possible to form diamond generating nuclei at a high density on the surface of the substrate.

Fe, C contained in the diamond particles
The proportion of one or more selected from the group consisting of o, Ni and Mn can be measured by an appropriate analysis method.For example, a diamond sample is heated and ashed using an electric furnace or the like to prepare a measurement sample. It can be measured by analyzing this using a known analyzer according to atomic absorption spectrometry, ICP emission spectroscopy, or the like.

The diamond particles may be natural diamond or synthetic diamond, and are not particularly limited.

The synthesized diamond particles can be obtained, for example, by a high-pressure synthesis method. That is, Fe, C
After dissolving o, Ni and Mn and graphite using an appropriate solvent, the resulting mixture is heated and pressurized to synthesize diamond particles.

[0015] Commercially available diamond particles can also be used. Since commercially available diamond particles are usually washed beforehand with an acid or the like, they contain various metals in arbitrary amounts. In the present invention,
Among the commercially available diamond particles, Fe, Co, Ni
And at least one selected from the group consisting of
Diamond particles containing at least 00 ppm can be appropriately selected and used.

The particle size of the diamond particles is not particularly limited and can be appropriately selected depending on the purpose.
Usually 0.1 to 500 μm, preferably 1 to 100
μm. If the particle size is less than 0.1 μm, the scratching effect may be reduced, while if it exceeds 500 μm, the nucleation density may be reduced.

It should be noted that the diamond particles used in the present invention do not need to be particularly diamond particles having a uniform particle size.

The scratching treatment can be performed, for example, by the following 1) ultrasonic cleaning method or 2) lapping method.

1) Ultrasonic cleaning method The scratching treatment can be performed by an ultrasonic cleaning method. That is, first, a solvent in which the diamond particles are dispersed is accommodated in a container such as a beaker. Then, the substrate is immersed in the solvent. Thereafter, the container is placed at a predetermined position in the ultrasonic cleaning device, and the ultrasonic cleaning device is operated for an appropriate time. Then, receiving the ultrasonic waves from the ultrasonic cleaning device, the diamond particles violently collide with the surface of the substrate in the container such as the beaker. As a result, it is possible to form minute scratches serving as diamond generation nuclei on the surface of the substrate.

The container is not limited to a beaker,
A container known per se can be appropriately selected and used.

The solvent is not particularly restricted but includes, for example, alcohols such as methanol, acetone, water, hydrofluoric acid and the like.

The amount of the diamond particles dispersed in the solvent is usually 0.1 to 100 ml per 100 ml of the solvent.
50 g, preferably 0.2 to 10 g. If the amount is less than 0.1 g, it may not be possible to form diamond generating nuclei at a high density on the surface of the substrate, while if it is more than 50 g, it may not be possible to obtain an effect corresponding thereto. .

The ultrasonic cleaning apparatus is not particularly limited, and a known apparatus can be used.

The time for performing the scratching treatment by the ultrasonic cleaning method can be appropriately selected according to the purpose, but is usually from 10 seconds to 5 hours, preferably from 1 to 60 minutes. If the time is shorter than 10 seconds, the diamond generating nucleus may not be formed sufficiently, and if it is longer than 5 hours, there may be no effect corresponding thereto.

2) Lapping method The above-mentioned scratching treatment can be performed by a lapping method. That is, the substrate is first placed on a rotatable lap plate. Then, the lap plate is rotated. Thereafter, a diamond slurry containing diamond particles is dropped on the rotating lap plate. Then, the dropped droplets of the diamond slurry move violently on the surface of the rotating lap plate. At this time, the surface of the substrate disposed on the surface of the lap plate is damaged by diamond particles contained in the droplets of the diamond slurry. As a result, a large number of fine nuclei serving as diamond generating nuclei can be formed on the surface of the substrate.

The wrap plate is not particularly limited.
It can be appropriately selected according to the purpose.

The speed of rotating the lap plate is as follows.
There is no particular limitation as long as diamond generation nuclei can be formed on the surface of the substrate, but it is usually 0.01 to 500 rpm, preferably 0.02 to 300 rpm. If the speed is lower than 0.01 rpm, diamond generating nuclei may not be sufficiently formed on the surface of the substrate. On the other hand, if the speed is higher than 500 rpm, an effect corresponding thereto may not be obtained.

Examples of the diamond slurry include a diamond slurry containing generally 0.01 to 5 g, preferably 0.02 to 1 g of diamond particles per 100 ml of a solvent. If the amount is less than 0.01 g, it may not be possible to form diamond generating nuclei at a high density on the surface of the substrate, while if it is more than 5 g, it may not be possible to obtain an effect corresponding thereto. .

As the solvent, the above-mentioned solvents can be used.

The time for performing the scratching treatment by the lapping method can be appropriately selected depending on the purpose, but is usually 10 seconds to 5 hours, preferably 1 to 60 minutes. If the time is shorter than 10 seconds, the diamond generating nucleus may not be formed sufficiently. On the other hand, if it is longer than 5 hours, the effect corresponding thereto may not be obtained.

As described above, diamond generating nuclei can be easily and simply formed on a surface of a substrate for synthesizing diamond with high density and high reproducibility.

(Synthesis of diamond) In order to synthesize diamond on the surface of a substrate on which a diamond generating nucleus has been formed at a high density by performing the above-described scratching treatment, various types of diamond vapor known per se are used. Synthetic methods can be used. Specifically, CVD method, PVD
Method, a PCVD method, a method combining these, or the like can be used. Among these, generally, various hot filament methods including the EACVD method, various direct current plasma CVD methods including the thermal plasma method, microwave plasma CVD methods including the thermal plasma method, and the like can be preferably used.

As the carbon source gas used in these diamond synthesis methods, for example, methane, ethane, propane,
Paraffinic hydrocarbons such as butane; olefinic hydrocarbons such as ethylene, propylene and butylene; acetylene;
Acetylene-based hydrocarbons such as allylene; diolefin-based hydrocarbons such as butadiene and allene; alicyclic hydrocarbons such as cyclopropane, cyclobutane, cyclopentane and cyclohexane; aromatics such as cyclobutadiene, benzene, toluene, xylene and naphthalene Hydrocarbons; ketones such as acetone, diethyl ketone and benzophenone; alcohols such as methanol and ethanol; other oxygen-containing hydrocarbons; amines such as trimethylamine and triethylamine; other nitrogen-containing hydrocarbons; Examples thereof include carbon oxide and carbon peroxide.

Among these, paraffinic hydrocarbons such as methane, ethane, and propane; alcohols such as ethanol and methanol; ketones such as acetone and benzophenone; amines such as trimethylamine and triethylamine; carbon dioxide; and carbon monoxide. Preferred, especially carbon monoxide. These may be used alone.
Two or more kinds may be used in combination as a mixed gas or the like.

These may be mixed with an active gas such as hydrogen or an inert gas such as helium, argon, neon, xenon or nitrogen.

The conditions for synthesizing diamond are not particularly limited. For example, the reaction pressure is usually 10 ⁻⁶ to 1.
0 is ³ Torr, preferably 1～760Torr. If the reaction pressure is lower than 10 ^-6 Torr, the diamond synthesis rate may be reduced. On the other hand, if higher than 10 ³ Torr is, 10 ³ Torr
There may be no further effect compared to the effect obtained at the time.

Since the surface temperature of the substrate varies depending on the means for activating the carbon source gas and the like, it cannot be specified unconditionally, but is usually from room temperature to 1,200 ° C., preferably from room temperature to 1,100 ° C. ° C. If the surface temperature of the substrate is lower than room temperature, the synthesis of crystalline diamond may be insufficient. On the other hand, when the temperature exceeds 1,200 ° C., etching of the synthesized diamond may easily occur.

The reaction time for synthesizing diamond is not particularly limited, and is preferably set appropriately according to the diamond synthesis speed so that the diamond has a desired thickness.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
The present invention is not limited to the following embodiments.

Example 1 The particle size was 1 μm or less, and F
e, containing 260 ppm, Co, 350 ppm and Ni, 6.9 ppm, and combining these with a total of 616.9 p.
A substrate as a 10 mm square p-type Si wafer was immersed in a beaker containing a scratching solution in which 0.2 g of pm-containing diamond particles were dispersed in 20 ml of acetone. Then, the beaker was placed at a predetermined position in an ultrasonic cleaning apparatus (Branson tabletop type; 2200), and the ultrasonic cleaning apparatus was operated to perform a scratching process on the substrate for 15 minutes. Thereafter, the substrate was taken out of the beaker and rinsed with acetone to prevent diamond particles from remaining on the substrate.

The F contained in the diamond particles
The amounts of e, Co and Ni were measured as follows.
First, 0.5 g of diamond particles were heated and ashed at a temperature of 800 ° C. in an electric furnace. The incinerated diamond is thermally decomposed using sulfuric acid, nitric acid and hydrofluoric acid,
It was dissolved with dilute nitric acid and filtered. At this time, the filtrate was made constant in volume using diluted nitric acid, and the insolubles were further heated and ashed, the insolubles were melted using potassium hydrogen sulfate, and the volume was made constant using diluted nitric acid. The dilute nitric acid solutions thus determined were combined into one, and this was combined with an ICP emission spectrometer (manufactured by Seiko Denshi Kogyo Co., Ltd .;
I using an emission spectrometer (SPS 1200VR)
CP emission spectroscopy was performed to measure the amounts of Fe, Ni and Co contained in the diamond particles of the sample.

Next, a microwave plasma CVD method (2.45 GH)
According to z), CO / H ₂ mixed gas is used as a source gas for 10 times.
/ 90sccm at a flow rate of 40 Torr
r, diamond was synthesized under the conditions that the substrate temperature was 900 ° C. and the reaction time was 1 hour.

As a result, 5.6 × 1
0 ⁹ / cm ² of a high density, the diamond occurs nuclei were formed. The formation density of the diamond generating nuclei was measured by SEM.

(Comparative Example 1) As diamond particles, F
Except for using diamond particles containing a total of 60 ppm of e, Co, Ni and Mn, the substrate was scratched in the same manner as in Example 1 to synthesize diamond.

As a result, 2.8 × 1
0 ⁷ / only at a density of cm ^2, diamond generated nuclei was not formed.

[0046]

According to the present invention, diamond generating nuclei can be easily and simply generated on a surface of a substrate for synthesizing diamond with high density and high reproducibility, thereby improving the productivity of diamond. be able to,
A method for forming a diamond generating nucleus can be provided.

Claims (2)

(57) [Claims] At least one member selected from the group consisting of Fe, Co, Ni and Mn is applied on a surface of a substrate for a total of 200 p.
A method for forming a diamond generating nucleus, wherein a scratching process is performed using diamond particles containing at least pm. 2. The method according to claim 1, wherein the diamond particles are Fe, Ni,
The method for forming a diamond generating nucleus according to claim 1, wherein the diamond particles contain at least 500 ppm of at least one selected from the group consisting of Co and Mn.