Diamond film structure with high thermal conductivity

• US 5,525,815 A
• Filed: 10/03/1994
• Issued: 06/11/1996
• Est. Priority Date: 10/03/1994
• Status: Expired due to Term

• Current Assignee: Diamond Innovations Incorporated (Sandvik AB)
• Original Assignee: General Electric Company
• Inventors: Einset, Erik O.
• Primary Examiner(s): LOKE, STEVEN HO YIN
• Application Number:
  US08/316,998
• Time in Patent Office: 617 Days
• Field of Search: 257/77, 257/712, 428/408, 427/212, 427/249, 423/446
• US Class Current: 257/77
• CPC Class Codes: C23C 16/271 using hot filaments
• CPC Class Codes: C23C 16/279 control of diamond crystallography
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A continuous diamond structure deposited by chemical vapor deposition is disclosed having at least two thermal conductivity diamond layers controlled by the diamond growth rate where one thermal conductivity diamond layer is grown at a high growth rate of at least one micron per hour for hot filament chemical vapor deposition and at least 2-3 microns per hour for microwave plasma assisted chemical vapor deposition, on a substrate such as molybdenum in a chemical vapor deposition chamber and at a substrate temperature that promotes the high growth rate, and the other thermal conductivity diamond layer is grown at a growth rate and substrate temperature lower than the high growth rate diamond layer. High growth rate and low growth rate diamond layers can be deposited in any sequence to obtain a continuous diamond structure that does not show distinguishable, separate, crystalline columnar layers, having improved thermal conductivity.

Claims

1. A continuous free-standing diamond film having an uninterrupted columnar structure of diamond crystals deposited by chemical vapor deposition having at least two thermal conductivity diamond layers, said diamond film comprising:

a thermal conducting diamond layer A having thermal conductivity in a direction perpendicular to a diamond film plane greater than thermal conductivity in a direction parallel to the diamond film plane, and a thermal conducting diamond layer B having thermal conductivity in the direction perpendicular to the diamond film plane equal to thermal conductivity in the direction parallel to the diamond film plane, with thermal conductivity in diamond layer A and diamond layer B respectively controlled by a different diamond growth rate and a different chemical vapor deposition substrate temperature, where diamond layer A is deposited at the diamond growth rate and substrate temperature greater than the diamond growth rate and substrate temperature used to deposit diamond layer B, wherein the substrate temperature for depositing diamond layer A is between 900°

-1000°

C. and the substrate temperature for depositing diamond layer B is between 700°

-850°

C., said substrate temperature being a temperature of a substrate in a chemical vapor deposition chamber used as a surface for depositing the diamond film, and said diamond film plane being the same plane as a surface of the substrate that said diamond film is deposited on in the chemical vapor deposition chamber, and diamond layer A being up to fifty times as thick as diamond layer B and diamond layer B being up to twenty percent as thick as diamond layer A.

2. A continuous free-standing diamond film according to claim 1 where said chemical vapor deposition is hot filament chemical vapor deposition or microwave plasma assisted chemical vapor deposition.

3. A continuous free-standing diamond film according to claim 2 where the microwave plasma assisted chemical vapor deposition diamond growth rate for diamond layer A is 3-5 microns per hour, and the growth rate for diamond layer B is 1.0-2.0 microns per hour.

4. A continuous free-standing diamond film according to claim 1 where the thermal conductivity layers A and B are deposited in any sequence provided there is at least one diamond layer A and one diamond layer B in the continuous free-standing diamond film.

5. A continuous free-standing diamond film according to claim 1 where the substrate temperature for layer A is between 900°

-960°

C. and the substrate temperature for layer B is about 800°

C.