Plasma etching of ZnS, ZnSe, CdS, and CdTe in electron cyclotron resonance CH4/H2/Ar and H2/Ar discharges

Abstract

Smooth anisotropic dry etching of ZnS, ZnSe, CdS, and CdTe in electron cyclotron resonance CH4/H2/Ar discharges at low pressure (1–25 mTorr) and low direct-current (dc) bias (−100 to −250 V dc) is reported. The presence of CH4 at low flow rates is necessary to obtain the best morphologies and to retain the stoichiometry of the surfaces, although H2/Ar discharges readily etch all four materials. Increasing the microwave power into the discharge at fixed dc bias produces significant increases in the resulting etch rates, while retaining the highly anisotropic nature of the pattern transfer.