Electron cyclotron resonance etching of InP, GaP, and GaAs in Ar, Ar/Cl-2, Ar/Cl-2/H-2, and Ar/Cl-2/H-2/CH4 plasmas is reported for substrate temperatures from 10 to 170 degrees C. Etch rates increased as a function of temperature for GaP and GaAs in an Ar/Cl-2 plasma. With the addition of H-2 or H-2/CH4 to the plasma, the GaP and GaAs etch rates decreased and were essentially temperature independent. In comparison, InP etch rates showed a strong temperature dependence regardless of plasma chemistry. At 170 degrees C, InP etch rates were greater than Gap and GaAs in the Ar/Cl-2/H-2 and Ar/Cl-2/H-2/CH4 plasmas. Atomic force microscopy was used to determine the root-mean-square roughness of the etched surfaces. The etched surface morphology for InP was strongly dependent on temperature and plasma chemistry while smooth pattern transfer was obtained for a wide range of plasma conditions for GaAs and Gap.