Chemical contribution of oxygen to silicon carbide plasma etching kinetics in a distributed electron cyclotron resonance (DECR) reactor

This paper deals with the influence of the oxygen additive on the fluorinated plasma etch rate of silicon carbide. The assumption according to which the oxygen has a direct contribution to silicon carbide etching, by chemical reaction with carbon atoms, is generally reported in the literature. Our etching experiments are performed in a distributed electron cyclotron resonance reactor, on both 3C- and 6H-SiC. An SF6/O-2 gas mixture (avoiding the presence of C species in the plasma), fluorine saturation conditions and constant ion bombardment energy and flux are used, allowing the study of O-2 contribution exclusively. In these conditions, our results demonstrate the neutrality of O-2 on SiC etching mechanisms. These results will be discussed reinforced both by several other experimental observations.