EFFECTS OF LEAKAGE CURRENT ON ISOTHERMAL CAPACITANCE TRANSIENT SPECTROSCOPY SIGNALS FOR MIDGAP LEVELS IN GAAS

The leakage current effects for the midgap levels in the electron-beam-metallized (EBM) Al/GaAs junction were studied by isothermal capacitance transient spectroscopy. In this junction, a new electron deep level which might be due to the surface defects induced during the EBM process was detected. The observed thermal emission time constants of the new deep level and the EL2 level (Ec -0.81 eV) in EBM-Al/GaAs were increased during the low-temperature annealing up to 355 °C, while the leakage current density in this junction was decreased down about 4×10-7 A/cm2. We represent that these behaviors of the midgap levels could be well explained by the effect of the leakage current in the Al/GaAs Schottky junction.