Etching mechanisms during plasma jet machining of silicon carbide

The material removal of the C- and Si-face of 4H-SiC using a 13.56MHz RF excited plasma jet source at atmospheric pressure using helium as feed gas and CF4 as reactive gas has been investigated. Additionally O2 is provided together with the peripherally injected N2 shielding gas and it is shown that a decrease of the etching rate with an increase of the O2 gas flow occurs.