Angle etch control for silicon carbide power devices

Silicon carbide plasma etching results are reported. Etching experiments are performed in a distributed electron cyclotron resonance reactor, using a SF6/O-2 gas mixture, on both 3C- and 6H-SiC. A special interest has been given to the slope of the etched sidewalls. Slopes between 30 degrees and 80 degrees have been achieved by varying selectivities between SiC and the SiO2 masking layer. Two parameters have been investigated to modulate selectivity: bias voltage and O-2 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. (C) 1996 American Institute of Physics.