Defect Evolution in Annealed p-type GaAsN Epilayers Grown by Metalorganic Chemical Vapour Deposition

Abstract

We have studied the evolution of electrically active defects in rapid thermally annealed p-type GaAsN epitaxial layers using deep level transient spectroscopy (DLTS). A continuous distribution of hole traps and an overlapping minority carrier trap are observed in the layers grown by metalorganic chemical vapour deposition. Rapid thermal annealing (RTA) in the temperature range 600-900°C for 30s created six hole traps HA1 (EV + 0.22 eV), HA2 (EV + 0.32eV), HA3 (EV + 0.38eV), HA4 (EV + 0.39eV), HA5 (EV + 0.55 eV), and HA6 (EV + 0.78 eV). Most of these defects are stable at 900°C, although their relative concentrations varied over the RTA temperature in this study. We discuss the origin of these hole traps based on previously reported hole traps in the literature. The increase in doping concentration in the annealed samples is also discussed. Show more