Analysis of trap states in AlGaN/GaN self-switching diodes via impedance measurements

The presence of trap states in self-switching diodes (SSD) based on an AlGaN/GaN heterojunction has been identified by means of their AC characterization between 75 kHz to 30 MHz in a wide temperature range, from 80 K to 300 K. Measurements allow us to determine two different characteristic energies of the traps, 12 meV and 61 meV, being associated to a distribution of surface states and one discrete bulk trap, respectively. The impact of the trapping effects on microwave detection at zero-bias has also been analyzed in the same temperature range, the measured responsivity showing an unusual enhancement and a low-frequency roll-off at low temperatures. •The impact of temperature on the performance of SSD has led to the identification of two kind of traps, one in the the bulk and the other in the surface.•The existence of traps in SSDs was initially predicted by the DC characterization•Impedance analysis was used to investigate the behavior of trapping mechanism, and to find an activation energy of charge traps.•The traps influence on the zero-bias microwave responsivity was also demonstrated.