Dry etching of germanium in magnetron enhanced SF6 plasmas

Magnetron enhanced reactive ion etching of germanium was investigated in SF6 plasmas. Ge etch rates were determined as a function of cathode power density (0.1–0.5 W/cm2), pressure (2–8 mTorr), and SF6 flow rate (2–11.5 sccm). Etch rate increased as pressure and flow rate were increased, but exhibited the unusual characteristic of decreasing as cathode power was increased. Auger electron spectroscopy measurements showed the presence of a sulfur residue (<1 at. %) upon etching, while scanning electron microscopy revealed that smooth etched surfaces were attained in SF6 magnetron enhanced plasmas.