SiC SOI Compliant Substrate for SiC and III-V Nitrides

The wide band-gap semiconductors SiC and III-V nitrides have been receiving greatly increased attention for high temperature and high power semiconductor devices, and for light emitting devices and laser applications at blue and UV wavelengths. Currently, one of the major hurdles in the development of these technologies is the substrate technology: (a) for SiC, substrates are extremely expensive and available only in small diameter sizes; (b) for the 111-N there is a complete lack of suitable single crystal substrate material which is lattice-matched. Epitaxy on substitute substrates usually results in films with high dislocation density. The SiC SOI structure, which has a very thin film of crystalline cubic 3C-SiC (50 - 1000A) on an insulator layer (SiO2) is a potential candidate for a low cost, large area, high quality compliant substrate. This approach could reduce the dislocation density in the grown films by force the threading dislocations downward towards the compliant oxide layer. In addition, the lattice mismatch for subsequent growth of SiC is eliminated and for GaN is greatly reduced (I%). Combining the formation of the SiC SOI structure and III-V nitride growth by MOCVD technology, a new and effective compliant substrate technology can be developed for these important materials.