Magnetron enhanced reactive ion etching of In0.5Ga0.5P was investigated in BCl3 plasmas. Etch rates were determined as a function of cathode power (0.2-0.5 W/cm(2)), BCl3 flow rate (3-12 seem), and pressure (2-10 mTorr), with rates as high as 0.35 mu m/min achieved. The addition of N-2, O-2, and Ar to BCl3 was ineffective in producing an etch rate increase. Changes in sheet resistance and photoluminescence of n- and p-type InGaP exposed to BCl3 plasmas were also investigated as a function of power, pressure, and etch duration. The n-type material was more susceptible to etch-induced damage than p-type material, suggesting that electron traps are produced by ion bombardment. Scanning electron micrographs showed etched surfaces to be smooth, with vertical sidewalls free of undercut.