CHARACTERIZATION OF GAAS GROWN ON SI EPITAXIAL LAYERS ON GAAS SUBSTRATES

GaAs has been grown on 9 and 18 angstrom thicknesses of epitaxial Si which was grown on GaAs (100) substrates. The GaAs on Si interface was characterized by cross-sectional transmission electron microscopy. A 9 angstrom thickness of Si on GaAs is pseudomorphic while 18 angstrom of Si is relaxed. Antiphase domains (APDs) were observed to annihilate near the GaAs on Si interface. Annihilation occurred within 100 angstrom of the interface for the 9 angstrom thickness of Si and around 1500 angstrom for the 18-angstrom Si case. From a detailed analysis of the APD shapes and sizes, we deduce the Ga-Ga bonds are energetically favored in the {111} planes and that two separate APD annihilation mechanisms occur. The growth mode of epitaxial Si on GaAs was also studied by in situ high-energy electron diffraction.