High-selectivity etching of polycrystalline 3C-SiC films using HBr-based transformer coupled plasma

We report a highly selective reactive ion etching process for 3C-SiC films using HBr-based chemistry in a commercial transformer coupled plasma (TCP) etcher. $SiO2$ and $Si3N4$ are employed as etch masks. Etch rates for SiC, $SiO2,$ and $Si3N4$ are measured as functions of chamber pressure and TCP source power. Etch rate ratios of 20:1 for $SiC/SiO2$ and 22:1 for $SiC/Si3N4$ are achieved. In addition, a SiC micromechanical resonator is fabricated to demonstrate integration of the etching process into conventional microfabrication technologies.