AFM observation of initial oxidation stage of 4H-SiC (0001) in electrochemical mechanical polishing

摘要

Single-crystal SiC (4H-SiC) is a promising next-generation semiconductor power-device material because of its excellent electronic and thermal properties. Electrochemical mechanical polishing (ECMP) is an effective way of finishing SiC surfaces. Using the ECMP process, the realization of a scratch-free and subsurface damage (SSD)-free surface is expected because the surface of SiC is softened by anodic oxidation and then removed by soft abrasives. Compared with chemical mechanical polishing (CMP), ECMP has a higher material removal rate (MRR) and a lower cost. However, protrusions tend to be generated on the oxide/SiC interface in the anodic oxidation process, which significantly increase the surface roughness. In this study, we observed the generation process of the oxide layer in the anodic oxidation of 4H-SiC (0001) by atomic force microscopy (AFM) observation, and the mechanism of the initial anodic oxidation is discussed.