CHARACTERIZATION OF GALLIUM ARSENIDE LAYERS ON INSULATORS WITH GERMANIUM INTERFACE ISLANDS.

Abstract

GaAs layers were grown by molecular beam epitaxy on single-crystal Ge-island layers, grown by zone melting recrystallization with SiO//2 capping layers, on the thermal oxide of Si wafers. It was found, by microprobe laser Raman scattering, that local tensile stresses of 2. 7 to 5. 5 kbar remained in single-crystal Ge islands after zone melting recrystallization. The GaAs layers, grown on the single crystal Ge islands, show smooth surfaces without any grain boundaries, while those, grown on the SiO//2 layers, have grain boundaries. The GaAs layers on the single-crystal Ge islands emit photoluminescence (PL), the intensity of which was almost comparable to that of GaAs layers on bulk Ge crystals. The stress in the GaAs layers on the Ge islands was also estimated from the photoluminescence spectra and was found to range from 2. 1 to 3. 2 kbar, which was in good agreement with the value for the underlying Ge islands obtained from Raman scattering.