Characterization and Optimization of Mbe Grown GaAs On Silicon On Sapphire Incorporating A Low Temperature Buffer

GaAs grown on silicon on sapphire (SOS) offers a major advantage over GaAs on Si because of the closer match in thermal expansion coefficients. In this paper, we compare MBE grown GaAs on orientated and selectively misoriented SOS with previously optimized GaAs on Si. The comparisons are made for active layer structures suitable for microwave low noise and power FET applications. Optimization of MBE growth on SOS used comparison criteria of morphology, surface defect density, X-ray spectra, electron mobility and 10K photoluminescence spectra as indicators of residual stress. MBE growth on 6° misoriented SOS produces nearly stress free layers with the incorporation of the low temperature buffer. Electrical profiles and wafer mapping of ion implanted GaAs on SOS with low temperature buffer show excellent confinement of the FET channel layer and good electrical activation.