JP2009013003A - Diamond manufacturing method and manufacturing apparatus - Google Patents

Abstract

An object of the present invention is to prevent occurrence of defects due to peeling of a diamond film on a heat dissipation holder during a diamond generation process, abnormal growth, and the like.
A holder is prepared in which diamond is not deposited on the surface, or even when diamond is deposited, a holder in which the deposited diamond does not peel at the holder temperature of 1300 ° C. to room temperature and diamond and carbide do not grow abnormally is prepared. Then, a diamond manufacturing method and a manufacturing apparatus are characterized in that after a substrate on which a diamond film is formed is placed on the holder, a diamond film is formed on the substrate. It is preferable that the vicinity of the substrate of the holder has a surface roughness Ra of 0.01 μm or less.
[Selection] Figure 1

Description

  The present invention relates to a diamond manufacturing method and a manufacturing apparatus, and relates to a diamond manufacturing method and a diamond manufacturing method for preventing deposition failure caused by separation and scattering of diamond deposited on a heat dissipating holder for setting a substrate on which diamond is deposited, and carbide. The present invention relates to a manufacturing apparatus.

Diamond has many unique properties that are unparalleled as a semiconductor material, such as high thermal conductivity, high electron / hole mobility, high breakdown field strength, low dielectric loss, and wide band gap. In particular, in recent years, ultraviolet light emitting elements utilizing a wide band gap and field effect transistors having excellent high frequency characteristics are being developed.
Various methods have been tried to produce diamond, and there are a method using a heating filament and a method using plasma excited by a microwave or the like. Other special ones include flame method, sputtering method, ion beam method, ultraviolet radiation, etc. With these excitation means, a mixed gas of hydrocarbon and hydrogen such as methane is decomposed and excited, and diamond is deposited on the substrate etc. Can be made.

For example, in the case of forming a film by microwave plasma CVD, it is possible to generate diamond on the substrate by using a gas obtained by mixing a carbon-based gas such as methane gas and hydrogen gas, and raising the pressure to about 800 to 1200 ° C. . When this method is performed, it is necessary to dissipate heat from the substrate on which the diamond is generated. In general, diamond is generated on the substrate after the substrate is placed on the heat dissipation holder.
At this time, the surface opposite to the substrate surface on which diamond is deposited, or the side surface of the substrate is placed in contact with the heat dissipation holder. Further, the heat radiation holder is brought into contact with a stage for receiving thermal energy, and heat is radiated by cooling the stage with water. A material having a high melting point and high thermal conductivity such as molybdenum is generally used for the heat dissipation holder for installing the substrate (see Patent Document 1).
JP 2005-508279 A

  When a diamond film is formed on the substrate, diamond or carbide may be deposited on a heat dissipation holder using a material such as molybdenum, and the deposited diamond or carbide may be peeled off during synthesis. Then, the diamond or carbide that has been peeled off and scattered adheres to the substrate on which diamond should be originally formed, thereby causing problems such as film formation defects. In addition, there is a problem called “abnormal growth” such as poor synthesis that occurs when diamonds or carbides generated abruptly increase. An object of the present invention is to prevent occurrence of defects, abnormal growth, and the like in a diamond production process.

  In order to solve the above-mentioned problems, the present invention is characterized in that when a substrate is placed on a heat dissipation holder to form a diamond film, a heat dissipation holder that does not deposit diamond on the surface or does not peel even when diamond is deposited is used. Have That is, by using a material such as silicon or silicon carbide that is difficult to peel diamond, or by reducing the surface roughness, the holder material can be prevented from being deposited and peeled off. It is possible to suppress film formation defects on the power substrate. In addition, by making the heat dissipation holder separable, even a thick diamond film can be changed at any time, and film formation defects can be suppressed by peeling and scattering.

The present invention adopts the following configuration in order to solve the above problems.
(1) In a diamond manufacturing method in which diamond is generated by a vapor phase synthesis method, a holder on which diamond is not deposited is prepared, or even when diamond is deposited, the deposited diamond does not peel at the holder temperature of 1300 ° C. to room temperature. In addition, after preparing a holder on which diamond and carbide do not grow abnormally, a diamond film is formed on the substrate after the substrate on which the diamond film is formed is placed on the holder. is there.
(2) The above (characterized in that at least the vicinity of the holder for setting the substrate on which the diamond film is formed is formed of any one of silicon, silicon carbide, silicon nitride, aluminum oxide, and aluminum nitride. It is a diamond manufacturing method as described in 1).
(3) The method for producing diamond according to (1) or (2) above, wherein at least the vicinity of the substrate for placing the substrate on which the diamond is deposited has a surface roughness Ra of 0.01 μm or less. It is.
(4) The diamond production according to any one of (1) to (3) above, wherein a holder for placing the substrate on which the diamond is to be formed is separable and at least a part of the holder can be replaced. Is the method.
(5) The holder according to any one of (1) to (4) above, wherein any one of diamond, oxide, nitride, and carbide is formed in advance before forming diamond on the substrate. The diamond production method according to any one of the above.

(6) A diamond manufacturing apparatus that generates diamond by a vapor phase synthesis method has a holder for setting a substrate on which a diamond film is to be formed, and the holder does not deposit diamond on the surface or even when diamond is deposited. In the holder temperature of 1300 ° C. to room temperature, the deposited diamond does not peel and diamond and / or carbide do not grow abnormally.
(7) The above (6) is characterized in that at least the substrate vicinity of the holder for setting the substrate on which the diamond is deposited is any one of silicon, silicon carbide, silicon nitride, aluminum oxide, and aluminum nitride. It is a diamond manufacturing apparatus of description.
(8) The diamond manufacturing apparatus according to the above (6) or (7), wherein at least the vicinity of the substrate on which the substrate on which the diamond is to be deposited is placed has a surface roughness Ra of 0.01 μm or less. .
(9) The diamond manufacturing apparatus according to any one of (6) to (8), wherein a holder on which the substrate on which the diamond is to be formed is separable is separable and at least a part of the holder can be replaced. is there.
(10) The holder according to any one of (6) to (9), wherein any one of diamond, oxide, nitride, and carbide is formed in advance before forming the diamond on the substrate. The diamond production apparatus according to any one of the above.

Examples of the material for the substrate on which the diamond film according to the present invention is formed include various materials such as single crystal diamond, polycrystalline diamond, and silicon substrate.
In addition, the holder used in the present invention is not particularly specified in shape, but may have a circular shape or a rectangular shape, and a substrate on which a diamond film is formed can be placed.
Furthermore, abnormal growth means that diamond or carbide produced on the holder has a higher film formation rate than other parts, and diamond or carbide increases rapidly. If this abnormal growth occurs when using the microwave plasma CVD method or the like, the plasma is concentrated at the abnormal growth occurrence portion, and the growth conditions in the periphery are changed. As a result, in other parts where diamond film formation is poor, for example, when a single crystal film is formed, the plasma concentrates on the part where abnormal growth occurs, so that the growth conditions change and a polycrystalline film is formed on the substrate. Will be.
Therefore, by using the diamond manufacturing method and manufacturing apparatus according to the present invention, the diamond deposited on the holder can be prevented from peeling and scattering, and the diamond peeled onto the substrate installed for the purpose of forming the diamond film. It is possible to prevent film formation defects caused by the adhesion of the film.

Next, it is preferable that at least a part of the material of the holder is silicon, silicon carbide, silicon nitride, aluminum oxide, or aluminum nitride. For example, by forming a 5 mmφ region in the vicinity of a substrate on which diamond is formed with silicon, silicon carbide, silicon nitride, aluminum oxide, or aluminum nitride, even when diamond is deposited on the holder, the adhesion with the diamond is improved. It is high and does not peel off as much as when using molybdenum material. Therefore, it is possible to prevent the occurrence of defects due to diamond adhering to the base material by peeling and scattering of diamond in the vicinity of the substrate.
It is preferable that the surface roughness of at least a part of the holder on which the substrate on which the diamond film is formed is set is Ra 0.01 μm or less. By setting the surface roughness to Ra 0.01 μm or less, it is possible to prevent the occurrence of defects due to diamond adhering to the base material by peeling and scattering in the vicinity of the substrate in the same manner as described above.

  It is preferable that the holder on which the substrate on which the diamond film is to be formed is separable and at least a part is replaceable. As a result, diamond may be deposited on the holder by synthesizing for a long time, and even if there is a part where the film thickness of diamond is increased and peeling is likely to occur by repeated use, before peeling Separation can be prevented by exchanging only that portion in advance. For example, by making it possible to replace the 5 mm square near the place where the substrate is installed, it is possible to suppress the occurrence of defects due to diamond peeling off and scattering to adhere to the base material.

  It is preferable that a film is formed in advance on the surface of the portion where the holder can be replaced before the diamond is formed. When synthesizing for a long time, peeling of the diamond film or abnormal growth occurs before exchanging the separable portion. Forming a diamond film with good adhesion by synthesizing in advance or forming an oxide, nitride, or carbide to prevent diamond peeling or abnormal growth Can do. In addition, by making it separable, it becomes easy to form a film of diamond, oxide, nitride, or carbide on the surface in advance.

  In the present invention, by changing the holder material and the surface roughness used when depositing diamond, the diamond film is peeled off and scattered during deposition to prevent deposition failure, and further, diamond is not deposited. By doing so, it is possible to prevent film formation condition fluctuations and film formation defects due to abnormal growth.

  In the case where a substrate is placed on a holder to form a diamond film, diamond is not formed on the surface of the holder, or is not peeled even when diamond is deposited. That is, the holder is made of a material such as silicon or silicon carbide that is difficult to peel diamond, or the surface roughness is reduced. In addition, even if a diamond film is formed on the surface, it can be separated and replaced. Film defects can be prevented.

  According to the diamond manufacturing method and manufacturing apparatus of the present invention, it is possible to prevent the occurrence of defects due to peeling of the diamond film on the heat dissipation holder during the diamond production process, abnormal growth, and the like.

Hereinafter, the present invention will be described in detail based on examples. The following examples are examples of the present invention and do not limit the present invention.
[Example 1]
An artificial Ib type single crystal {100} substrate having a size of 3 mm × 6 mm and a thickness of 0.7 mm was prepared, and a 50 mmφ-3 mmt holder on which the substrate can be set was prepared. The holder material was prepared from five types of silicon, silicon carbide, silicon nitride, aluminum oxide, and aluminum nitride.
Epitaxial growth by microwave plasma CVD was performed on the substrate placed in the holder. The substrate temperature was 1100 ° C. and the pressure was 90 torr. The introduced gas was methane 200 sccm (standard cubic cm) and hydrogen 1000 sccm. Film formation was performed for a total of 20 hours.
After 20 hours of film formation, the introduction of microwaves was stopped and the system was cooled to room temperature.
Diamond deposition was observed on the holder surface for all of the five types used at this time, but no diamond peeling was observed. We have also successfully deposited single-crystal diamond on a single-crystal substrate.

[Comparative Example 1]
A holder made of a molybdenum material was prepared. Except that, epitaxial growth was performed on the substrate in the same manner as in Example 1. Here, the surface roughness of the holder was Ra: 0.02 μm.
As a result, after 35 hours from the start of film formation, the diamond deposited on the holder made of molybdenum was peeled off and scattered to adhere to the Ib single crystal substrate. As a result, the diamond film on the single crystal substrate became defective.
[Example 2]
Prepare an artificial Ib type single crystal {1 10} substrate of 2 mm × 5 mm and thickness 0.4 mm, 40 m
A holder of mφ-7 mmt was prepared. The holder material was molybdenum, and Ra: 0.01 μm by mirror polishing.
Epitaxial growth by microwave plasma CVD was performed on the substrate placed on the mirror-polished holder. The substrate temperature was 1050 ° C. and the pressure was 70 torr. The introduced gas was methane 180 sccm (standard cubic cm) and hydrogen 1200 sccm. Film formation was performed for a total of 25 hours. After the film formation for 25 hours, the introduction of the microwave was stopped and the system was cooled to room temperature.
No diamond deposition was observed on the holder surface used at this time. As a result, diamond was successfully deposited on a single crystal substrate.

[Example 3]
An artificial Ib type single crystal {110} substrate having a size of 5 mm × 5 mm and a thickness of 1.0 mm was prepared, and a holder of 50 mm □ −3 mmt was prepared. The holder material was molybdenum, and Ra: 0.01 μm by mirror polishing.
As shown in FIG. 1, a groove having a width of 1 mm for fitting a separable portion was formed in a portion near the substrate of a holder material on which a substrate on which a diamond film is to be formed is placed, and the separable portion was fitted on the holder. By adopting such a structure, the vicinity of the substrate on the holder can be separated and replaced.
Epitaxial growth by microwave plasma CVD was performed on the substrate placed in the holder. The substrate temperature was 1100 ° C. and the pressure was 90 torr. The introduced gas was methane 200 sccm (standard cubic cm) and hydrogen 1000 sccm. When 40 hours had elapsed, the film formation was temporarily stopped, the separable part of the holder was replaced, and the film formation was further performed for 40 hours, and the film formation was performed for a total of 80 hours.

2 is a cross-sectional view taken along the line II-II in FIG. 1 for explaining the exchange of the separable part of the holder. As shown in FIG. 2, the separable portion of the holder material fitted before epitaxial growth was separated from the fitting groove. Then, after replacing | exchanging to a new holder separable part, the film-forming for 40 hours was performed by said method.
As a result, although the deposition of the diamond film was observed on the holder, no separation was observed at the replaced holder part near the substrate, and there was no influence on the single crystal substrate due to the separation or scattering of the diamond film. Successful film formation.

[Comparative Example 2]
In the same manner as in Example 3, synthesis was temporarily stopped in 40 hours, but the separable part of the holder was not changed, and film formation was further performed for 40 hours, and film formation was performed for a total of 80 hours.
As a result, peeling occurred at the separable portion of the holder after 32 hours from the start of additional film formation, and scattered diamond adhered to the single crystal substrate, resulting in film formation failure.

[Example 4]
An artificial Ib type single crystal {100} substrate of 5 mmφ and thickness 1.2 mm is prepared, and 65 mmφ−
A 5 mmt holder was prepared. The holder material was molybdenum, and Ra: 0.01 μm by mirror polishing. As shown in FIG. 3, a separable portion having a width of 1.5 mm was produced on the holder in the vicinity of the substrate.
Five types of holders are prepared, and diamond, SiO ₂ , SiN are provided in separable parts.
An SiC was vapor-deposited on the surface, and no SiC was vapor-deposited on the surface. Using each holder, epitaxial growth by microwave plasma CVD was performed on the substrate. The substrate temperature was 1200 ° C. and the pressure was 50 torr. The introduced gas was methane 180 sccm (standard cubic cm) and hydrogen 900 sccm. When 50 hours had elapsed, the film formation was temporarily stopped, the separable part of the holder was replaced, and the film formation was further performed for 50 hours, for a total of 100 hours.

As a result, diamond was deposited on the diamond film, but no peeling occurred. In the case of depositing SiO ₂ , SiN, or SiC, diamond deposition was not observed. In the case where no film was formed on the surface in advance, abnormal growth occurred after 40 hours, and the diamond on the single crystal was polycrystallized.

6 is a plan view showing a holder and a substrate used in Example 3. FIG. It is II-II arrow sectional drawing in FIG. 6 is a plan view showing a cylindrical holder and a substrate used in Example 4. FIG.

Claims (10)

In a diamond manufacturing method in which diamond is generated by a vapor phase synthesis method, a holder on which diamond is not deposited is prepared, or even when diamond is deposited, the deposited diamond does not peel off at the holder temperature of 1300 ° C. to room temperature. And a diamond manufacturing method, comprising: preparing a holder on which carbides do not grow abnormally; setting a diamond film on the holder; and depositing a diamond film on the substrate. 2. The holder for installing the substrate on which the diamond film is to be formed is formed of at least the vicinity of the substrate by any of silicon, silicon carbide, silicon nitride, aluminum oxide, and aluminum nitride. Diamond manufacturing method. The diamond manufacturing method according to claim 1 or 2, wherein at least the vicinity of the substrate for mounting the substrate on which the diamond is deposited has a surface roughness Ra of 0.01 µm or less. The diamond manufacturing method according to any one of claims 1 to 3, wherein a holder for installing the substrate on which the diamond film is to be formed is separable and at least a part thereof is replaceable. The diamond according to any one of claims 1 to 4, wherein the holder is formed in advance with a diamond, oxide, nitride, or carbide film before forming the diamond film on the substrate. Production method. In a diamond production apparatus for producing diamond by a vapor phase synthesis method, the apparatus has a holder for setting a substrate on which a diamond is to be formed, and the holder temperature does not deposit diamond on the surface or even when diamond is deposited. A manufacturing apparatus characterized in that deposited diamond does not peel at 1300 ° C. to room temperature, and diamond and / or carbide do not grow abnormally. The diamond manufacturing method according to claim 6, wherein at least the vicinity of the holder for installing the substrate on which the diamond is to be deposited is one of silicon, silicon carbide, silicon nitride, aluminum oxide, and aluminum nitride. apparatus. The diamond manufacturing apparatus according to claim 6 or 7, wherein at least the vicinity of the substrate on which the substrate on which the diamond film is formed is placed has a surface roughness Ra of 0.01 µm or less. The diamond manufacturing apparatus according to any one of claims 6 to 8, wherein a holder on which the substrate on which the diamond film is to be formed is separable and at least a part thereof is replaceable. 10. The holder according to claim 6, wherein any one of diamond, oxide, nitride, and carbide is formed in advance before forming the diamond on the substrate. Diamond manufacturing equipment.

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