Experimental analysis of temperature dependence of deep-level capture cross-section properties at the Au oxidized InP interface

Abstract

Deep levels in unintentionally doped InP liquid encapsulated Czochralsky material have been studied by deep-level transient spectroscopy (DLTS) technique. Five electron traps are observed between 80 and 270 K labeled T1, T3, T4A, T4B, and T5. Trap concentrations are generally below 1013 cm−3. The capture cross sections for levels T1, T3, and T5, determined assuming an exponential time dependence of the capacitance transient, show a quite large variation with temperature which is consistent with the multiphonon emission process. In each case under this process, the binding energy term is much lower than the capture activation energy term. An unusual increase of the DLTS peak magnitude as the emission rate decreases leads us to analyze the capacitance signal as a multi-exponential transient. Each DLTS peak is then decomposed into two components from which the specific parameters have been extracted, activation energy, binding energy, and the experimental dependence of the capture cross section versus temperature for each contribution. The agreement between the theoretical model and experimental results is very good for the three levels T1, T3, and T5 under all experimental conditions, including the incomplete capture.