Photocatalysis-Assisted Chemical Mechanical Polishing of SiC Wafer using a Novel SiO2@TiO2 Core-Shell Composite Nanoparticles Slurry

Abstract

Silicon carbide (SiC) is considered as a promising third-generation semiconductor material, but the surface fabrication of SiC wafer is very challenging. Photocatalysis-assisted chemical mechanical polishing of Si-face SiC wafer using a novel SiO2@TiO2 core–shell composite nanoparticles slurry is developed, for attaining high removal efficiency and high surface quality of SiC wafer. The preparation of the SiO2@TiO2 core–shell particles is introduced, and the characteristics of the new composite particle abrasive are studied through scanning electron microscopy, transmission electron microscopy, size distribution, X-ray diffraction and Fourier infrared spectroscopy analysis. Polishing performances of SiC wafer using the slurry with the prepared SiO2@TiO2 composite nanoparticles under UV light are evaluated. The material removal rate (MRR) by the slurry with the SiO2@TiO2 composite nanoparticles presents much higher than that by the slurry without the SiO2@TiO2 particles. Meanwhile, the ultra-smooth surface with the low roughness and atomic step structure could be acquired. The relative removal schematic of the slurry with the photo-active composite nanoparticles abrasive towards the polishing of the SiC surface is proposed.