IC1 plasma etching of III–V semiconductors

Etch rates in excess of 1.5 μm/min for InP and InSb, 1.2 μm/min for GaAs and 0.7 μm/min for GaSb at room temperature were obtained in electron cyclotron resonance IC1/Ar plasmas at low additional rf power (150 W). There was little dependence of etch rate on microwave power over the range 400–1000 W for InP, and selectivities of 6–10 over mask materials such as SiO2, SiNx, and W were typical. Smooth surface morphologies were obtained over a wide range of plasma parameters for GaAs and GaSb, while preferential loss of P led to rough morphologies for InP at high rf powers. IC1-based plasmas appear to be promising universal etchants for Ga- and In-based III–V semiconductors.