Prebreakdown and breakdown effects in AlGaN/GaN heterostructure field effect transistors

Prebreakdown and breakdown effects under high electric fields in AlGaN/GaN heterojunction field effect transistors were studied. In the subthreshold regime, at large drain-to-source voltages $\text{(>80\hspace{0.17em}}\mathrm{V}\mathrm{),}$ along with the gate leakage current, a significant source current was measured. For a wide range of gate-to-source bias voltages in OFF and ON regimes, the breakdown voltage was limited by a rapid buildup of the source current, rather than a process dominated by gate leakage.