Defect reduction by thermal annealing of GaAs layers grown by molecular beam epitaxy on Si substrates

Abstract

Post growth thermal annealing has been used to reduce the defect density of GaAs layers grown on Si substrates by molecular beam epitaxy. Transmission electron microscopy indicates a 100× reduction of the true defect density. Twins and stacking faults were eliminated entirely. Most misfit dislocations were confined within the first ∼150 Å GaAs layer and formed a regular and narrow network along the Si/GaAs interface. Similar results were obtained from an ion implanted and annealed specimen.