Summary of deep level defect characteristics in GaN and AlGaN

The characteristics of defects that are predicted to be dominant for n-GaN or p-GaN are reviewed, and compared to measurements. Measurements are discussed to extract the concentration, transition energy, charge state, and lattice relaxation, each of which can be predicted from theory. Additional considerations are discussed related to the defects that are expected to occur in highest concentration. All of the native defects with transitions in the band gap are expected to act as minority carrier traps, in spite of the predominance of characterization using majority carrier devices. Defects detected by deep level transient spectroscopy are also frequently cited as being associated with a dislocation based on the capture kinetics. Possibilities for other capture mechanisms exist and are modeled along with capture at a dislocation in order to provide a method to distinguish between the mechanisms. This work provides a framework for systematically progressing towards identifying the composition of defects.