Claims
- 1. A method for synthesizing a diamond film on a substrate in a reaction vessel in a low-pressure gaseous phase, consisting essentially of
- preparing a raw material gas from a carbon source and hydrogen, said carbon source selected from the group consisting of solid carbon, a hydrocarbon, a hydrocarbon containing O or N in a bonding group, and carbon tetrachloride, and
- activating said raw material gas by a thermoelectron-radiating material and by formation of a DC plasma to deposit the diamond film on a surface of the substrate,
- wherein the surface of the substrate is heated from 600.degree. to 1200.degree. C., the thermoelectron-radiating material is heated to at least 1,600.degree. C. and is connected to a negative pole while the substrate to be coated is connected to a positive pole, the DC plasma is formed between the thermoelectron-radiating material and the substrate by applying a direct current voltage from a direct current power source and a pressure within the reaction vessel, in which the plasma is formed, is set between 100 and 500 Torr.
- 2. A method for synthesizing a diamond film according to claim 1, further comprising controlling the temperature of the substrate by using a substrate-supporting table having a means for cooling the substrate by flowing a coolant through the substrate-supporting table, wherein the temperature of the substrate can be adjusted by adjusting the flow of coolant in the substrate-supporting table.
- 3. A method for synthesizing a diamond bulk material on a substrate in a reaction vessel in a low-pressure gaseous phase, comprising
- preparing a raw material gas from a carbon source and hydrogen, said carbon source selected from the group consisting of solid carbon, a hydrocarbon, a hydrocarbon containing O or N in a bonding group, and carbon tetrachloride, and
- activating said raw material gas by a thermoelectron-radiating material and by formation of a DC plasma to deposit the diamond bulk material on a surface of the substrate,
- wherein the surface of the substrate is heated from 850.degree. to 1200.degree. C., the thermoelectron-radiating material is heated to 2,200.degree. C. or more and is connected to a negative pole while the substrate to be coated is connected to a positive pole, the DC plasma is formed between the thermoelectron-radiating material and the substrate by applying a direct current voltage from a direct current power source, the electric power applied for forming the DC plasma is 50 W/cm.sup.3 or more per unit volume of DC plasma-forming space, the ratio of carbon atoms to hydrogen atoms in the raw material gas is between 1% and 10%, and a pressure within the reaction vessel, in which the plasma is formed, is between 150 and 500 Torr.
- 4. A method for synthesizing a diamond bulk material on a substrate in a reaction vessel in a low-pressure gaseous phase, comprising
- preparing a raw material gas from a carbon source and hydrogen, said carbon source selected from the group consisting of solid carbon, a hydrocarbon, a hydrocarbon containing O or N in a bonding group, and carbon tetrachloride, and
- activating said raw material gas by a thermoelectron-radiating material and by formation of a DC plasma to deposit the diamond bulk material on a surface of the substrate,
- wherein the surface of the substrate is heated from 850.degree. to 1200.degree. C., the thermoelectron-radiating material is heated to 2,200.degree. C. or more and is connected to a negative pole while the substrate to be coated is connected to a positive pole, the DC plasma is formed between the thermoelectron-radiating material and the substrate by applying a direct current voltage from a direct current power source, the electric power applied for forming the DC plasma is 50 W/cm.sup.3 or more per unit volume of DC plasma-forming space, and a pressure within the reaction vessel, in which the plasma is formed, is between 150 and 500 Torr.
- 5. A method for synthesizing a diamond film on a substrate according to claim 1, wherein the heating of the substrate surface and the thermoelectron-radiating material is controlled by using a substrate-supporting table having a means for cooling the substrate by flowing a coolant through the substrate-supporting table, and the density of the direct current is 50 W/cm.sup.3 or more.
- 6. A method for synthesizing a diamond bulk material on a substrate in a reaction vessel in a low-pressure gaseous phase according to claim 4, in which the growth rate of diamond is 20 microns per hour or more.
Priority Claims (3)
Number |
Date |
Country |
Kind |
61-173365 |
Jul 1986 |
JPX |
|
62-75282 |
Mar 1987 |
JPX |
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62-116598 |
May 1987 |
JPX |
|
Parent Case Info
This application is a continuation of now abandoned application, Ser. No. 07/392,286 filed on Aug. 11, 1989, which was a divisional of Ser. No. 07/76,721 filed on Jul. 22, 1987, U.S. Pat. No. 4,900,628.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4734339 |
Schachner et al. |
Mar 1988 |
|
4740263 |
Imai et al. |
Apr 1988 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
59-232991 |
Dec 1984 |
JPX |
Non-Patent Literature Citations (2)
Entry |
Sawabe et al, "Growth of Diamond Thin Films by Electron Assisted CVD", Applied Physics Letters, 1985. |
Matsumoto et al, "Growth of Diamond Particles from Methane Hydrogen Gas", Nat Inst. for Research in Inorg. Mat., Japan J. of Materials Science 17 (1982) 3106-3112. |
Divisions (1)
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Number |
Date |
Country |
Parent |
76721 |
Jul 1987 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
392286 |
Aug 1989 |
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