Rapid thermal processing of implanted GaAs reveals a definitive sequence in the damage annealing and the electrical activation of ions. Removal of implantation‐induced damage and restoration of GaAs crystallinity occurs first. Irrespective of implanted species, at this stage the GaAs isn‐type and highly resistive with almost ideal values of electron mobility. Electrical activation is achieved next when, in a narrow anneal temperature window, the material becomesn‐ orp‐type, or remains semi‐insulating, commensurate to the chemical nature of the implanted ion. Such a two‐step sequence in the electrical doping of GaAs by ion implantation may be unique of GaAs and other compound semiconductors.