Removal mechanism of 4H- and 6H-SiC substrates (0001 and 0001¯) in mechanical planarization machining

This article describes the mechanical planarization machining of SiC substrates involving the Si face (0001) and C face ([Formula: see text]) of N-type (doping nitrogen) 4H-SiC, N-type 6H-SiC, and V-type (doping vanadium) 6H-SiC with a sol–gel polishing pad. The polishing results indicate that the C face, which has a surface roughness of less than 2 nm, is smoother than the Si face (>10 nm), and the material removal rate of the C face is higher than that of the Si face. The removal mechanism of SiC substrates was investigated with regard to the wear debris and subsurface structure through transmission electron microscopy, and instrumented nanomechanical tests were performed to further reveal the removal mechanism by nanoindentation and nanoscratching. The analysis results demonstrate that the difference in the material removal rates of the Si face and C face depends on the material removal scale together with the mechanical properties of SiC substrates. The processing of SiC substrates is dominated by the mechanical removal of SiC material during mechanical planarization machining.