Theoretical Studyof Oxidation Mechanism of SiC onSi-Face ((0001) Surface) Using MnO4–

Oxidation mechanisms of the Si-face ((0001) surface) of SiC by MnO4– were investigated using density functional theory calculations to elucidate the reactions occurring during chemical mechanical polishing (CMP). On the Si-face terminated with OH and H groups, MnO4– readily abstracts a hydrogen atom from a Si–H site and subsequently binds to the resulting vacant Si site through one of its oxygen atoms, forming a stable intermediate with a Si–O–MnO3H structure. This intermediate then reacts with surface OH and H groups. Reactions at Si–OH sites with MnO4– were also examined and found to be unfavorable due to high reaction barriers. To assess the effect of acidic conditions, reactions involving MnO4H (protonated MnO4–) were analyzed. The results indicate that the reaction barriers are lower for MnO4H than for MnO4–, which would be one factor contributing to the higher oxidation efficiency of MnO4– under low-pH conditions. Comparison with H2O2 indicates that MnO4– exhibits lower activation barriers and forms more reactive surface intermediates, which would be key factors for achieving efficient CMP on the Si-face.