SMOOTH ETCHING OF SINGLE-CRYSTAL 6H-SIC IN AN ELECTRON-CYCLOTRON-RESONANCE PLASMA REACTOR

Single-crystal 6H-SiC has been etched using a CF4/O2 gas mixture in an electron cyclotron resonance (ECR) plasma reactor. ECR etching result s in SiC surfaces which are extremely smooth, without the problematic micromasking effects which have been reported to result from reactive ion etching in capacitively coupled radio-frequency plasma reactors. T he effects of microwave power, total pressure, substrate temperature, and substrate bias on the etch rate, surface morphology, etch profile, and etch selectivity have been evaluated. The etch rate increases wit h increasing power and bias, and decreasing pressure. However, high bi ases lead to enhanced etching in regions adjacent to sidewall features . Improved etch profiles and selectivity are obtained with lower appli ed substrate bias.