LOW-TEMPERATURE GAAS EPITAXIAL-GROWTH ON SI(100) BY MOLECULAR-BEAM EPITAXY AND THE POSTGROWTH RAPID THERMAL ANNEALING

This article presents low temperature GaAs epitaxial growth on Si(100) by molecular beam epitaxy and the improvement of epitaxial quality by post-growth rapid thermal annealing. The silicon wafer was ex-situ cleaned by spin-etch method to obtain a hydrogen-passivated surface before wafer loading. An in-situ cleaning process for hydrogen removal was carried out in the growth chamber by heating the silicon substrate to a low pre-growth desorption temperature (250-600-degrees-C) prior to epitaxial growth. Epitaxial films were grown at 250-580-degrees-C with strained layer superlattice to reduce defect density. The epitaxial films were characterized by cross-sectional transmission electron microscopy, scanning electron microscopy, photoluminescence, and double crystal X-ray diffraction. The GaAs epitaxial quality improves with pre-growth desorption temperature and deposition temperature. The epitaxial films were treated by rapid thermal annealing to improve epitaxial quality. Optimum annealing conditions of epitaxial films grown at different temperature were also investigated.