BCl3/Ar discharges provide rapid, smooth pattern transfer in GaAs, AlGaAs, GaP, and GaSb over a wide range of plasma conditions. At high BCl3-to-Ar ratio there is significant surface roughening on GaSb, which is correlated with the presence of B- and Cl-containing residues detected by Auger electron spectroscopy. BCl3/N2 discharges provide similar etch rates to BCl3/Ar, but when used with photoresist masks lead to rough morphologies on the semiconductor materials due to enhanced dissociation and redeposition of the resist. Etch rates with electron cyclotron resonance discharges are up to two orders of magnitude higher than for rf-only conditions.