LAUSR

Abstract Au Schottky barrier contacts (SBDs) were DC sputter deposited on Si doped n-type GaAs at a power of 150 W. Deep-level transient spectroscopy (DLTS) and Laplace DLTS were used to characterize the sputter-induced defects near the surface of the GaAs. In this study, I-V and C-V measurements showed that the sputter deposited diodes had a significantly lower barrier height and a higher free carrier density. Using DLTS, it was found that this sample contained seven defects – three of them were metastable while one of the others was highly dopant dependent. The energy levels of these defects are Ec – 0.046 eV, Ec – 0.22 eV, Ec – 0.30 eV, Ec – 0.55 eV, Ec – 0.56 eV, Ec – 0.83 eV and Ec – 0.84 eV. The EL2 defect was not observed in the sputtered samples, but one of the sputter-induced defects emitted in the same range as the EL2, however, it had two components and their DLTS signatures (Ec – 0.83 eV and Ec – 0.84 eV) differed significantly from that of the EL2. By applying different bias conditions (−2 V and zero V) for annealing procedures, the metastable defects (Ec – 0.30 eV and Ec – 0.56 eV) were transformed into each other. The pre-factor obtained from transformation rate of Ec – 0.56 eV → Ec – 0.30 eV under reverse bias was 3 × 1015 s−1 which is related to free carrier emission.