Growth of Thick GaN Films on Mixed-Polarity Buffer by Halide Vapor Phase Epitaxy
利用混合极性制备多孔缓冲层及其在GaN厚膜外延中的应用

GaN thin films with mixed-polarity were initially grown on (0001) sapphire substrates by molecular beam epitaxy (MBE).The samples were etched by alkali solution,and porous GaN films were formed.GaN thick films were grown on the porous GaN layers by hydride vapor phase epitaxy (HVPE).These HVPE-GaN epilayers were characterized by atomic force microscopy,X-ray diffraction,and photoluminescence spectroscopy.The results indicate that the crystalline quality of HVPE-GaN is improved by using the porous GaN buffer,as the stress is reduced markedly.