Damage-free and Atomically-flat Finishing of Single Crystal SiC by Combination of Oxidation and Soft Abrasive Polishing

Abstract

Plasma-assisted polishing (PAP), which combined the irradiation of atmospheric-pressurewater vapor plasma and ceria abrasive polishing, was proposed for the finishing of difficult-to-machine materials, such as single crystal SiC, GaN, sapphire and diamond. In the case of PAP was applied to a 4H-SiC-Si face, an oxide layer (SiO2) was generated after plasma irradiation and it was removed by polishing using soft abrasives. In this way, a damage-free and atomically-flat 4H-SiC-Si face could be obtained. In this study, soft abrasive polishing (CeO2)of a plasma-oxidized SiC-Si face and a thermally oxidized SiC-C face was respectively conducted. The generation of a well-ordered one-bilayer step-terrace structure on both of the polished Si face and C face was confirmed by atomic force microscopy (AFM). However, due to the high temperature of thermal-oxidation, many pits were generated on SiC-C face after polishing.