Chemical polishing of hexagonal p-type 6H-SiC surfaces by HF/Na2O2 solutions

Abstract

In this paper, we present an experimental method on the etching reaction of p-type 6H-SiC, etching that was carried out in HF/Na2O2 solutions. The morphology of the etched surface was examined with varying Na2O2 concentration, etching time and temperature solution. The surfaces of the etched samples were analyzed using Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and Photoluminescence. The surface morphology of samples etched in HF/Na2O2 is shown to depend on the solution composition and bath temperature. The investigation of the HF/Na2O2 solutions on 6H-SiC surface shows that as Na2O2 concentration increases, the etch rate increases to reach a maximum value at about 0.6 M and then decreases. A similar behaviour has been observed when temperature of the solution is increased. The maximum etch rate is found for 80 °C. Taking account the result a new polishing etching solution of 6H-SiC has been developed. In addition, the result is very interesting when to date no chemical polishing solution has been developed on silicon carbide (SiC). Finally, we have proposed a dissolution mechanism of the silicon carbide in HF/Na2O2 solutions.