We have investigated the electrical performance of mesa-isolated GaAs pn-junction diodes to determine the plasma-induced damage effects from reactive ion and reactive ion beam etching (REBE). A variety of plasma chemistries (SiCl4, BCl3, BCl3/Cl2, and Cl2) and ion energies ranging from 100 to 400 eV were studied. We have observed that many of the reactive ion etching BCl3/Cl2 plasmas and RIBE Cl2 plasmas yield diodes with low reverse-bias currents that are comparable to the electrical characteristics of wet-chemical-etched devices. The reverse-bias leakage currents are independent of surface morphology and sidewall profiles.