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