Plasma assisted polishing of single crystal SiC for obtaining atomically flat strain-free surface

A novel polishing technique combined with the irradiation of atmospheric pressure plasma was proposed for the finishing of a silicon carbide material. The irradiation of helium-based water vapor plasma efficiently oxidized the surface of single-crystal 4H–SiC (0 0 0 1), and a nanoindentation test revealed that the hardness of SiC decreased by one order of magnitude compared with that of the unprocessed surface. Plasma-assisted polishing using a CeO2 abrasive enabled us to improve the surface roughness of a commercially available SiC wafer without introducing crystallographical subsurface damage, and a scratch-free atomically flat surface with an rms roughness of 0.1 nm level was obtained.