Deep Level Charactenzation in Semi-Insulating GaAs by Photo-Induced Current and Photo-Hall Effect Transient Spectroscopy

Abstract

Deep levels in semi-insulating (SI) GaAs single crystals have been studied by the photo-induced current transient spectroscopy (PICTS) and photo-hall effect transient spectroscopy (PHETS) A method of measuring defect level density in SI-GaAs using PHETS has been developed and apphed for the measurement of the EL6 density Properties of the defect levels EL6 and EL2 were investigated by companng their density distnbution in the crystals and their annealing behavior The density distnbution of EL2 in the wafer showed the similar pattern to the dislocation density The density distribution of EL6, however, showed the inversely related pattern to that of EL2 The density of both EL2 and EL6 levels increased similarly by the annealing at 600 to 1000°C and diminished by the annealing at 1100°C These expenmental results were well explained by the tentatively assumed defect models of EL2 (As_GaV_Ga) and EL6 (As_GaAs₁)