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.