Sulfur Hexafluoride Reactive Ion Etching of (111) Beta-SiC Epitaxial Layers, Grown on (111) TiC Substrates

Results of reactive ion etching studies, performed in SF6, on (111) oriented B-SiC and TIC are presented. The B-SiC etch rate increased with increasing SF 6 pressure and with increasing incident RF power. The contribution of sputter etching, relative to chemical etching, decreased with increasing SF6 pressure and increased with increasing incident RF power. As-etched surfaces were free of residue under all etching conditions. The as-etched surface morphologies were smooth, and essentially independent of etching conditions at incident RF powers>1000 W;-<100 W, the surface morphology became progressively rougher as the incident RF power was decreased. The electrical properties of the as-etched ~-SiC surfaces ranged from passive to very conductive, and did not correlate with etching conditions. The as-etched sidewalls of B-SiC and TiC mesas were vertical under all conditions investigated