Defect energy levels in carbon implanted n-type homoepitaxial GaN

Abstract

While carbon doping is known to increase the resistivity of GaN, highly resistive layers for device isolation can also be obtained by ion implantation. In this study, we report on the electrical characterization of C-implanted n-type homoepitaxial GaN. Our investigation, carried out by capacitance-voltage measurements and deep level/minority carrier transient spectroscopy, revealed the presence of nine majority carrier traps in the 0.2-1.3 eV energy range, below the conduction band edge, and of four minority carrier traps, in the 0.1-1.4 eV energy range, above the valence band edge. The net-donor compensation mechanism and the behavior of defect centers are studied as a function of the annealing temperature in the 100-1000 °C range. While the former is explained in terms of dynamic annealing, the latter is discussed in the light of the present experimental results and those found in the literature.