A study on inductively coupled plasma etch rate of HgCdTe at cryogenic temperature

Etching at cryogenic temperature can reduced the etch-induced damage in HgCdTe during etch process, which is important to fabricate high performance IRFPAs (Infrared Focal Plane Arrays) detectors. The etch rates of HgCdTe were examined to be similar at different temperatures and the smoothness of the etched surface improves at cryogenic temperature using a standard process, and the etch rates of different CH4/Ar/H2 plasmas at 123K were also investigated. Addition of H2 increases the roughness of etched sidewall while has little effect on etched bottom surface roughness, and SiO2 with a contact layer of ZnS functioned well as etch mask during cryoetching under CH4/Ar/H2 plasmas.