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