Etching characteristics and mechanisms of SiC thin films in inductively-coupled HBr-Ar, N2, O2 plasmas

Etch characteristics and mechanisms of SiC thin films in HBr-Ar, HBr-N2, and HBr-O2 inductively-coupled plasmas were studied using a combination of experimental and modeling methods. The etch rates of SiC thin films were measured as functions of the additive gas fraction in the range of 0–100% for Ar, N2, and O2 at a fixed gas pressure (6 mTorr), input power (700 W), bias power (200 W), and total gas flow rate (40 sccm). The plasma chemistry was analyzed using Langmuir probe diagnostics and a global (zero-dimensional) plasma model. The good agreement between the behaviors of the SiC etch rate and the H atom flux could suggest that a chemical etch pathway is rather controlled by the gasification of carbon through the CHx or CHxBry compounds.