Wafer precursor prepared for group III nitride epitaxial growth on a composite substrate having diamond and silicon carbide layers, and semiconductor laser formed thereon

• US 8,513,672 B2
• Filed: 11/23/2010
• Issued: 08/20/2013
• 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:
  US12/952,278
• Publication Number:
  US 20110064105A1
• Time in Patent Office: 1,001 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 wafer precursor for semiconductor devices comprising:

a substrate of single crystal silicon carbide that is at least two inches in diameter; and

a layer of diamond on a first face of said silicon carbide substrate;

wherein an opposite face of said silicon carbide substrate is prepared for Group III nitride epitaxial growth thereon.

2. A wafer precursor according to claim 1 comprising a Group III nitride active structure on said prepared opposite face.

3. A wafer precursor according to claim 2 wherein said Group III nitride active structure includes at least one heterostructure.

4. A wafer precursor according to claim 3 comprising a buffer layer on said silicon carbide substrate and between said substrate and said at least one heterostructure.

5. A wafer precursor according to claim 1 wherein said silicon carbide substrate is at least three inches in diameter.

6. A wafer precursor according to claim 1 wherein said silicon carbide substrate is at least 100 mm in diameter.

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

8. A wafer precursor according to claim 1 comprising a plurality of individual active structures on said prepared opposite face of said silicon carbide substrate.

9. A semiconductor laser comprising:

a diamond substrate;

a single crystal silicon carbide layer on said diamond substrate;

at least a first cladding layer on said silicon carbide layer;

a Group III nitride active portion on said at least a first cladding layer; and

at least a second cladding layer on said active portion.

10. A semiconductor laser according to claim 9 further comprising a buffer layer between said silicon carbide layer and said at least a first cladding layer.

11. A semiconductor laser according to claim 9 comprising a polycrystalline diamond substrate.

12. A semiconductor laser according to claim 9 wherein said silicon carbide has a polytype selected from the 3C, 4H, 6H and 15R polytypes of silicon carbide.