Initial stages of growth of GaAs on silicon (211) substrates by migration-enhanced molecular beam epitaxy

Abstract

The nucleation of GaAs films grown by the alternate deposition of gallium and arsenic monolayers on Si(211) and (100) substrates has been studied in situ using Auger and energy-loss spectroscopies, and low-energy electron diffraction. Films were observed to become continuous at much smaller thicknesses when grown on (211), as compared to (100), substrates. This implies that the nucleation site density is much greater on the (211) surface, as expected from the very high step density for this orientation. The observed growth was consistent with a layer-by-layer growth mode.