The Growth of GaAs on Si by Molecular Beam Epitaxy

Abstract

ABSTRACTSuccessful growth of GaAs on Si has recently been demonstrated. This work is directed toward an understanding of the processes occurring during the growth and their effects on the quality of the GaAs epilayers. Reflection High Energy Electron Diffraction monitoring of the growth in situ shows that the islands that are initially formed coalesce into an epilayer with a 2×4 surface reconstruction. Ion channeling indicates that the crystallinity of the entire epilayer improves with coverage. Substantial reordering of the material occurs when buffer layers grown at low temperatures are annealed at 575°C before and during further growth at this temperature. Comparison of 300 nm layers differing in the growth temperature of the first 100 nm shows no variation in the crystallinity as determined by ion channeling. Surface morphology degrades, however, and 77K photoluminescence intensity rises with the initial growth temperature. The optical and structural properties of 2μm thick films are also discussed.