IDENTIFICATION OF ELECTRON-IRRADIATION DEFECTS IN SEMIINSULATING GAASBY NORMALIZED THERMALLY STIMULATED CURRENT MEASUREMENTS

Primary defects induced by 1 MeV electron irradiation have been quanti tatively studied in semi-insulating (SI) GaAs by using normalized ther mally stimulated current spectroscopy, a new technique. Defects identi cal to (or similar to) those known in the thermally stimulated current literature as T-6(0.13 eV), T-5(0.34 eV), and T-4(0.31 eV) are produ ced at rates 0.70, 0.08, and 0.23 cm(-1), respectively; T-5 is also a strong trap in unirradiated SI GaAs. The defects T-6 and T-4 correspo nd closely to the irradiation-induced traps E2(0.14 eV) and E3(0.30 eV ), studied extensively by deep-level transient spectroscopy and Hall-e ffect measurements and assigned to the As vacancy. We thus infer that traps T-6 and T-4 (and probably also T-5) in SI GaGs have As-vacancy character.