Reliability of Quasi-vertical GaN on Silicon Schottky Barrier Diodes With SiO₂ Passivation Layer Under On-State Stress Bias

On-state stress induced device degradation of gallium nitride quasivertical Schottky barrier diode (SBD) with SiO2 passivation layer was investigated in this article. The devices were stressed at room temperature by biasing them separately at three distinct voltages for 500 s. The longer-term degradation was seen to be dominated predominantly by electron trapping in the oxide passivation layer. Less-severe degradation was observed in passivated devices in comparison with control devices without SiO2 passivation. The control devices were found to exhibit degradation due to the influence of bulk traps near to the metal/GaN interface. Moreover, the anode was held at zero voltage for 500 s to analyse the electron de-trapping mechanism during the recovery phase of SBDs. Current-voltage characteristics of the SBDs were measured to monitor the evolution of forward voltage and barrier height through periodic interruption under stress and recovery. A power-law model and universal recovery function were utilized to evaluate the parameter shifts with respect to time for each phase, respectively. The results demonstrate that border and bulk oxide traps associated with the passivation layer lead to the trapping and de-trapping of electrons. Furthermore, long-time constant bulk oxide traps are thought to be the contributing factor in the partial recovery, indicating that few electrons emit from these traps in the short-term recovery phase.