Spectroscopic characterization of the electrical properties of Fe implants on GaInP/GaAs

We have investigated the structural and electrical properties of GaInP/GaAs epilayers implanted with Fe atoms to produce a shallow high resistivity layer. Proton-induced x-ray emission channeling measurements indicate that the substitutional fraction of the Fe implanted atoms decreases with increasing postimplant annealing temperatures. However, current-voltage analyses as a function of temperature indicate that a high temperature postimplantation annealing is necessary for the removal of the implantation-induced damage and for the activation of an efficient and stable electrical compensation process, which we have ascribed to the interplay between a deep donor and a deep acceptor, located at E-C-0.50 eV and E-V+0.74 eV, respectively. We have focused our attention on the latter deep level, attributed to the Fe2+/3+ related acceptor trap, which we have directly identified and characterized by spectral photocurrent analyses and by capacitance transient spectroscopy carried out under below-band-gap illumination, which stimulated the direct emission/trapping of carriers from the deep trap.