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.