Angle etch control for silicon carbide power devices

Abstract

Silicon carbide plasma etching results are reported. Etching experiments are performed in a distributed electron cyclotron resonance reactor, using a SF6/O2 gas mixture, on both 3C- and 6H-SiC. A special interest has been given to the slope of the etched sidewalls. Slopes between 30° and 80° have been achieved by varying selectivities between SiC and the SiO2 masking layer. Two parameters have been investigated to modulate selectivity: bias voltage and O2 additive flow. A wide range of selectivities (from 1 to 6.5) has been obtained for suitable etch rate (100 to 270 nm/min) with very smooth surfaces.