Comparative study of the substrate-film interfaces of GaAs grown by two molecular beam epitaxial methods

Carrier concentration profiles in the region of a substrate-film homojunction for n- and p-type GaAs were studied using a capacitance-voltage carrier profiling technique. The GaAs films were grown on GaAs substrates by molecular beam epitaxy (MBE) and by gas-source molecular beam epitaxy (GSMBE). The GaAs homojunctions grown by MBE exhibited a much larger reduction in carrier concentration than those prepared by GSMBE. The highest quality interface, without an observable depletion region, was obtained when an additional hydrogen plasma was used during heat treatment prior to GSMBE growth.