Effects of oxidizer concentration and abrasive type on interfacial bonding and material removal in 4H-SiC polishing processes

Abstract

Determination of chemical effects involved in material removal during the polishing process of 4H-SiC has been a challenge. In this study, the polishing processes of 4H-SiC under the action of diamond and SiO₂ abrasive in different concentrations of H₂O₂ solutions are investigated by reactive force field molecular dynamics simulations. It is found that 4H-SiC can be oxidized by H₂O₂ solution at the atomic scale, but the chemical reaction alone does not lead to material removal. An increase in the concentration of H₂O₂ solution and the mechanical action of abrasives can promote the oxidation of 4H-SiC. Since the mechanical removal dominates material removal when polishing 4H-SiC with diamond abrasive, there is no clear pattern in the effect of H₂O₂ solution concentration on material removal. Nevertheless, the removal of atoms associated with chemical bonds dominates material removal when polishing 4H-SiC with SiO₂ abrasive. Therefore, the damage and atomic removal of 4H-SiC are lower. Since the H₂O₂ solution can increase the total number of bonds between 4H-SiC and SiO₂ abrasive, an increase in the concentration of H₂O₂ solution can improve the material removal rate. These findings can provide guidance for the 4H-SiC polishing process in terms of abrasive and oxidizer selection.