Characterization of GaAs grown on Si epitaxial layers on GaAs substrates

GaAs has been grown on 9 and 18 Å 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 Å thickness of Si on GaAs is pseudomorphic while 18 Å of Si is relaxed. Antiphase domains (APDs) were observed to annihilate near the GaAs on Si interface. Annihilation ocurred within 100 Å of the interface for the 9 Å thickness of Si and around 1500 Å for the 18-Å Si case. From a detailed analysis of the APD shapes and sizes, we deduce that GaGa 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.