Low-dislocation-density GaAs epilayers grown on Ge-coated Si substrates by means of lateral epitaxial overgrowth

Abstract
Single-crystal GaAs layers have been obtained by means of lateral epitaxial overgrowth seeded within stripe openings in a SiO2 mask over GaAs layers grown on Ge-coated Si substrates. Transmission electron microscope and scanning cathodoluminescence studies indicate that the laterally overgrown GaAs layers have a dislocation density of less than 104 cm−2, compared to 107–108 cm−2 for the GaAs layers grown directly on the Ge/Si substrates. Initial experiments indicate that the electrical properties of the laterally overgrown layers are comparable to those of conventional GaAs epilayers grown on single-crystal GaAs substrates.