BCl3/Ar and BCl3/N-2 plasma chemistries were compared for patterning of InP, InAs, InSb, InGaAs, InGaAsP, and AlInAs. Under electron cyclotron resonance conditions etch rates in excess of 1 mu m/min can be achieved at room temperature with low additional rf chuck power (150 W). The etch rates are similar for both chemistries, with smoother surface morphologies for BCl3/Ar. However, the surfaces are still approximately an order of magnitude rougher (as quantified by atomic force microscopy) than those obtained under the same conditions with Cl-2/Ar. InP surfaces etched at high BCl3-to-Ar ratios have measurable concentrations of boron- and chlorine-containing residues.