Effect of chemical action on the chemical mechanical polishing of β-Ga2O3(100) substrate

Abstract

Chemical mechanical polishing (CMP) is an essential processing step to realize ultra-precision machining of the fragile material Ga2O3 crystal and obtain ultra-smooth and undamaged crystal surface. The chemical auxiliary polishing mechanism of Ga2O3 in the CMP process was studied considering that the chemical action directly affects the CMP result. First, H3PO4 and NaOH were used to regulate the pH of slurry. This slurry was then applied to the CMP experiment of Ga2O3, and the corrosion test of Ga2O3 was implemented in H3PO4 and NaOH solutions. Second, the influence of the slurry with different acids or bases on the polishing result was analyzed. Finally, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the corrosive action on the chemical structure of the crystal surface. Results showed that the slurry prepared by H3PO4 was more suitable for the CMP of Ga2O3 than that prepared by NaOH. The polishing efficiency was enhanced by approximately 20% and the surface quality was improved, with surface roughness of 0.21 nm. This study provides a reference for preparing the slurry of Ga2O3.