Control of the properties of wide bandgap a-SiC: H films prepared by RF PECVD method by varying methane flow rate

摘要

The influence of increase in flow rate of CH_4 in a source gas mixture of SiH_4 + CH_4 + H2 for the preparation of high-quality wide band gap a-SiC: H film by the RF PECVD method has been studied. We have been able to increase the optical gap of the film by increasing CH_4 flow rate under appropriate deposition conditions. These films are structurally better which also shows good opto-electronic properties. This has been achieved mainly by using CH_n (where n = 3, 2 or 1) precursors in the plasma as the etchant for weak bonds on the growing surface of a-SiC: H films.