Dominant factors and their action mechanisms on material removal rate in electrochemical mechanical polishing of 4H-SiC (0001) surface

Abstract Slurryless electrochemical mechanical polishing (ECMP) has been confirmed as a highly efficient damage-free polishing technique for SiC wafers. To increase the material removal rate of ECMP, it is essential to have a better understanding of the anodic oxidation mechanism of SiC to obtain a much higher anodic oxidation rate. In this study, we investigated the effects of electrolyte temperature, surface damage, doping concentration, and strain on the anodic oxidation rate of SiC. All these factors were found have a promotional effect on the anodic oxidation of SiC. The promotional effects of processing-induced damage and doping on SiC anodic oxidation were attributed to the processing-induced residual strain and doping-induced strain on the SiC surface, which were observed by Raman spectroscopy. The relationship between anodic oxidation rate and strain on the SiC surface was quantitatively investigated by applying a strain-controllable anodic oxidation device. Both compressive and tensile strains were found to increase the anodic oxidation rate of SiC. The promotion mechanism of the strain on the anodic oxidation of SiC was studied by conductive atomic force microscopy observations. This study is expected to be an important guide for improving the efficiency of ECMP and will contribute to the practical application of ECMP.