First-principles insights into the synergistic chemical–mechanical removal mechanism of 4H-SiC in chemical mechanical polishing

Abstract

Chemical mechanical polishing (CMP) is a key process for improving the surface quality of 4H-SiC. Although experimental progress has been made, the atomic-level mechanism of the synergistic effects between oxidants and abrasives remains unclear. For this study, by means of first-principles calculations, a two-step oxidation-removal simulation pathway is proposed. First, a MnO₄⁻-4H-SiC (0001) reaction model is established to reveal the mechanism of SiC oxide layer formation. Then, an adsorption model for Al₂O₃ abrasives on the SiO₂/4H-SiC (0001) surface is constructed, exploring the mechanisms of bond formation and cleavage at the contact interface and clarifying the atomic-level material removal pathway. Meanwhile, XPS analysis verifies the existence of Si–O and Al–O–Si bonds, which attests to the reliability of the simulation outcomes. This study provides an in-depth analysis of the CMP process mechanism on an atomic-scale basis and offers theoretical guidance for the precision planarization of third-generation semiconductor materials.