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相比于蓝宝石,6H-SiC是制作GaN高功率器件更有前途的衬底。本文研究了表面处理如研磨、化学机械抛光对6H-SiC衬底表面特性的影响。用显微镜、原子力显微镜、拉曼光谱、卢瑟福背散射谱表征了衬底表面。结果表明经过两步化学机械抛光后提高了表面质量。经第二步化学机械抛光后的衬底具有优异的表面形貌、高透射率和极小的损伤层,其表面粗糙度RMS是0.12nm。在该衬底上用MOCVD方法长出了高质量的GaN外延膜。
Compared to sapphire, 6H-SiC is a more promising substrate for GaN high power devices. In this paper, the effects of surface treatment such as grinding and chemical mechanical polishing on the surface properties of 6H-SiC substrate were investigated. The surface of the substrate was characterized by microscopy, atomic force microscopy, Raman spectroscopy and Rutherford backscattering spectroscopy. The results show that after two steps of chemical mechanical polishing to improve the surface quality. After the second chemical mechanical polishing substrate has excellent surface morphology, high transmittance and minimal damage layer, the surface roughness RMS is 0.12nm. A high-quality GaN epitaxial film was grown on the substrate by MOCVD.