Epitaxial lateral overgrowth of gallium nitride on silicon substrate

Abstract

Many studies have been undertaken on how to reduce defects and dislocations in gallium nitride films due to the lattice mismatch and difference in thermal conductivity between GaN and the substrate. The ability of epitaxial lateral overgrowth (ELO) for extended defect reduction in the heteroepitaxial growth of III–V semiconductors has been demonstrated and utilized in the deposition of GaN. The purpose of this study is to experimentally investigate the effect of growth conditions on GaN film growth in the MOCVD process. The effect of different buffer layers was studied for the second growth of GaN in the ELO process. It was found that ELO significantly improved the morphology of GaN films. The best such films obtained in this work, as measured by X-ray rocking curve and photoluminescence, were obtained when a low-temperature GaN buffer layer was used prior to the deposition of the GaN seeding layer and the GaN overgrowth layer.