Conductivity Modulation in Vertical GaN PiN Diode: Evidence and Impact

This work presents the experimental evidence and impact of the conductivity modulation in the direct-bandgap GaN vertical PiN diode, by using pulse-mode and time-resolved characterizations as well as high-speed board-level switching tests. For the first time, the dependence of the forward transient behaviors in the vertical GaN PiN diode on time, current and temperature has been comprehensively investigated. The reduced ON-resistance (RON) with longer ON-state time, at higher current level or higher temperature verifies the conductivity modulation in the vertical GaN PiN diode in transient/dynamic level. Thanks to the limited trapping effects and conductivity modulation, the vertical GaN PiN diode can deliver superior dynamic RON performance after switching from high-voltage OFF state, showing great potential for high-power and high-efficiency power conversion.