Silicon carbide layer on diamond substrate for supporting group III nitride heterostructure device

• US 7,579,626 B2
• Filed: 02/06/2006
• Issued: 08/25/2009
• Est. Priority Date: 01/22/2004
• Status: Active Grant

• Current Assignee: Wolfspeed, Inc.
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Saxler, Adam William
• Primary Examiner(s): Smoot; Stephen W
• Application Number:
  US11/347,953
• Publication Number:
  US 20060138455A1
• Time in Patent Office: 1,296 Days
• Field of Search: 257/76
• US Class Current: 257/77
• CPC Class Codes: H01L 21/02378 Silicon carbide
• CPC Class Codes: H01L 21/02527 Carbon, e.g. diamond-like carbon
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 29/1602 Diamond
• CPC Class Codes: H01L 29/778 with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface H01L29/803 takes precedence

Abstract

A high power, wide-bandgap device is disclosed that exhibits reduced junction temperature and higher power density during operation and improved reliability at a rated power density. The device includes a diamond substrate for providing a heat sink with a thermal conductivity greater than silicon carbide, a single crystal silicon carbide layer on the diamond substrate for providing a supporting crystal lattice match for wide-bandgap material structures that is better than the crystal lattice match of diamond, and a Group III nitride heterostructure on the single crystal silicon carbide layer for providing device characteristics.

Claims

1. A high power, wide-bandgap structure that exhibits reduced junction temperature and higher power density during operation and improved reliability at a rated power density, said structure comprising:

a diamond substrate for providing a heat sink with a thermal conductivity greater than silicon carbide;

a single crystal silicon carbide layer of at least two inches diameter on said diamond substrate for providing a supporting crystal lattice match for wide-bandgap material structures that is better than the crystal lattice match of diamond, said diamond substrate on said single crystal silicon carbide layer in a size substantially similar to that of said single crystal silicon carbide layer; and

a Group III nitride heterostructure on said single crystal silicon carbide layer for providing device characteristics.

2. A structure according to claim 1 comprising a polycrystalline diamond substrate.

3. A structure according to claim 1 wherein said silicon carbide layer is semi-insulating.

4. A structure according to claim 1 further comprising a Group III nitride buffer layer on said silicon carbide layer for providing a crystal and electronic transition between said heterostructure and said silicon carbide layer.

5. A structure according to claim 4 wherein said buffer layer comprises aluminum nitride.

6. A structure according to claim 1 wherein said silicon carbide has a polytype selected from the 3C, 4H, 6H and 15R polytypes of silicon carbide.

7. A structure according to claim 1 further comprising respective ohmic contacts to said heterostructure.

8. A structure according to claim 1 packaged in a high-thermal conductivity material.

9. A packaged structure according to claim 8 wherein said high-thermal conductivity material comprises diamond.