Claims
- 1. A process for producing diamond, comprising the steps of:
- (a) bringing both a columnar cathode and a tubular pilot anode, provided concentrically around said cathode set apart with a clearance from said cathode, into proximity to a plasma jetting port of a front end portion of a tubular main anode, provided concentrically around said pilot anode set apart with a clearance from said pilot anode,
- (b) applying a discharge voltage across said cathode and said pilot anode to convert a pilot gas introduced in the clearance between said cathode and said pilot anode to a plasma,
- (c) after step (b), moving the cathode which is close to said pilot anode away from said pilot anode along a common axis,
- (d) holding the discharge voltage across said cathode and said pilot anode to a first preselected voltage,
- (e) after step (d), applying a discharge voltage across said cathode and said main anode to convert a main gas introduced in the clearance between said main anode and said pilot anode to a plasma,
- (f) after step (e), moving at least the pilot anode which is close to the main anode away from the main anode along said common axis while maintaining the discharge voltage across said cathode and said pilot anode at the first preselected voltage,
- (g) holding the discharge voltage across said cathode and said main anode to a second preselected voltage, and
- (h) jetting the main gas in the form of plasma from said jetting port toward a substrate while generating a main arc between said main anode and said cathode and maintaining the second preselected voltage, thereby producing diamond on the substrate.
- 2. A process as set forth in claim 1, wherein said pilot gas is argon gas or another inert gas and said main gas is a mixed gas of hydrogen gas or an inert gas and a gas comprised of a carbon compound used as a feedstock gas.
- 3. A process as set forth in claim 1, which introduces a gas including a feedstock gas into the plasma jet from the plasma jetting port of said main anode.
- 4. A process as set forth in claim 3, wherein said pilot gas is argon gas or another inert gas, said main gas is hydrogen gas or an inert gas, and said feedstock gas is a gas comprised of a carbon compound.
- 5. A process as set forth in claim 1, wherein said diamond is produced in a chamber having a reduced pressure, and atmospheric gas is introduced into said chamber from a gas introduction port in a wall of said chamber.
- 6. A process as set forth in claim 5, wherein said pilot gas is argon gas or another inert gas, said main gas is hydrogen gas or an inert gas, and said atmospheric gas is a gas comprised of a carbon compound.
- 7. A process as set forth in claim 5, wherein said pilot gas is argon gas or another inert gas, said main gas is hydrogen gas or an inert gas, and said atmospheric gas is a mixed gas comprised of a gas comprising a carbon compound, an oxidizing gas, a halogen gas, and a halogenated hydrogen gas.
Priority Claims (2)
Number |
Date |
Country |
Kind |
4-113852 |
May 1992 |
JPX |
|
4-282006 |
Oct 1992 |
JPX |
|
Parent Case Info
This application is a division of application Ser. No. 08/057,823 filed May 7, 1993, now pending.
US Referenced Citations (13)
Foreign Referenced Citations (2)
Number |
Date |
Country |
62-124080 |
Jun 1987 |
JPX |
1-33096 |
Feb 1989 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Ohtake et al., "Diamond Film Preparation by Arc Discharge Plasma Jet Chemical Vapor Deposition in the Methane Atmosphere", J. Electrochem. Soc., vol. 137, No. 2, Feb. 1990. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
57823 |
May 1993 |
|