Diamond crystal forming method

• US 5,607,560 A
• Filed: 10/10/1995
• Issued: 03/04/1997
• Est. Priority Date: 03/25/1993
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hirabayashi, Keiji, Yamagami, Atsushi
• Primary Examiner(s): Breneman, R. Bruce
• Assistant Examiner(s): MCDONALD, RODNEY GLENN
• Application Number:
  US08/541,592
• Time in Patent Office: 511 Days
• Field of Search: 204/192.12, 204/192.15, 204/192.16, 204/192.22, 204/192.25, 204/192.26, 204/192.28, 423/446, 117/108, 117/929
• US Class Current: 204/192.15
• CPC Class Codes: C23C 14/0611 Diamond
• CPC Class Codes: C23C 14/345 using substrate bias
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: C30B 23/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/04 Diamond

Abstract

A diamond crystal forming method with which a diamond crystal is formed on a substrate by a sputtering process uses high-frequency energy in the frequency range of 40 MHz to 250 MHz to form plasma.

Claims

1. A diamond crystal forming method comprising the steps of:

positioning a substrate and a target in a reaction vessel;

supplying a sputtering gas to the reaction vessel; and

forming a diamond crystal on the substrate by applying high-frequency energy in the frequency range of 40 MHz to 250 MHz to the target for performing a plasma discharge while applying a DC bias voltage to the substrate, wherein the DC bias voltage satisfies the following formula;

-20 V≦

plasma potential-bias voltage applied to the substrate≦

10 V.

2. A diamond crystal forming method according to claim 1, further comprising the step of keeping a temperature of the substrate in the range of 300°

C. to 1400°

C.

3. A diamond crystal forming method according to claim 1, further comprising the step of forming the diamond crystal while a pressure inside the reaction vessel is controlled to be kept in the range of 1 Pa to 10⁴ Pa.

4. A diamond crystal forming method according to claim 1, further comprising the step of using a sputtering gas that contains at least hydrogen and oxygen.

5. A diamond crystal forming method according to claim 4, further comprising the step of setting a ratio of oxygen atoms to hydrogen atoms to a range of 0.005 to 1 and keeping a temperature of the substrate in the range of 400°

C. to 900°

C. so that a crystal is formed as a flat-plate diamond with ratio of height to horizontal width being not larger than 1/4.

6. A diamond crystal forming method according to claim 1, further comprising the step of forming a granular diamond crystal with a ratio of height to horizontal width not less than 1/3.

7. A diamond crystal forming method according to claim 1, wherein the step of plasma discharge is in the frequency range of 80 MHz to 200 MHz.