Planarization of C-face 4H-SiC substrate using Fe particles and hydrogen peroxide solution

We have proposed a surface planarization method for silicon carbide (SiC) substrates using Fe abrasive particles and hydrogen peroxide (H2O2) solution. In this proposed method, the SiC surface is first oxidized by hydroxyl radicals generated by the decomposition of H2O2 on the surface of Fe abrasive particles, and then an oxide layer is formed on the SiC substrate. This layer is then mechanically and/or chemically removed by Fe abrasive particles and H2O2 solution, resulting in a smooth and damage-free SiC surface. In this study, the chemical mechanical planarization of a 4H-SiC (0 0 0 1¯) C-face substrate by our proposed method was examined. The morphology was observed by phase-shift interferometric microscopy, Nomarski differential interference contrast microscopy and atomic force microscopy. The subsurface damage on the processed surface was evaluated by high-resolution transmission electron microscopy. These observations showed that the surface roughness of the SiC substrate was markedly improved and that a damage-free and scratch-free SiC surface was obtained. These results provide useful information for preparing high-integrity SiC substrates with high efficiency.

► We have proposed a precision polishing method for single-crystal 4H-SiC C-face substrates.
► Our proposed method utilizes hydroxyl radicals generated on the Fe abrasive particles in hydrogen peroxide solution.
► Our proposed method yields an atomically flat and damage-free 4H-SiC C-face surface.