The small gate overvoltage margin is of real concern in p-gate GaN HEMTs in converter applications. Recently, ICeGaN® (Integrated Circuit Enhancement-mode GaN) device deploys a monolithically integrated power IC interface to expand the static operation window to be similar to those of Si MOSFET and Si IGBT. However, the dynamic response of the IC interface under nanosecond gate bias (VG) overshoot, as well as the gate reliability under megahertz switching frequency (fSW), have never been studied. This work addresses this gap by developing a new circuit to generate the application-like V G overshoot profiles with dVG/dt up to 10 V Ins andfsw up to 3 MHz. The IC interface is shown to respond in nanosecond and clamp the VG,IN below 7 V under an external V G overshoot up to 80 V and dVG/dt of 7 V Ins. Uniquely for p-gate GaN devices, ICeGaN shows no degradation under long-term overvoltage stress under 30-V VG overshoot at 3-MHzfsw. This is the first report of the dynamic response of GaN monolithic gate protection ICs under ultra-fast overshoot. Test results reveal that the on-chip IC interface can substantially enhance dynamic gate reliability and robustness of p-gate GaN HEMTs.

GaN monolithic bidirectional switch (MBDS) has the potential to enable revolutionary advances in AC power conversion. Despite the availability of industrial 650−V MBDS engineering samples, there have been very few reliability reports of GaN MBDS, and none has been performed up to kilovolt. Here we demonstrate a GaN enhancement-mode (E-mode) MBDS with high breakdown voltage (BV) over 3 kV in both polarities, and for the first time, study the dynamic stability and reliability of a GaN MBDS up to ±1.2kV blocking voltage. The device deploys a dual p-GaN junction termination extension (D JTE) design to achieve high BV. Pulse I-V, HTGB, and HTRB measurements were performed with an emphasis on the unique stress for bidirectional devices, including the reverse bias blocking and the impact of high-side gate. We find the dynamic on-resistance of the JTE-MBDS is sensitive to the low-side gate bias but insensitive to the high-side gate bias. Under the HTRB test, the MBDS shows larger shifts in on-resistance and threshold voltage under the reverse bias blocking compared to those under the forward bias blocking. Physical mechanisms are discussed and supported by TCAD simulations. Overall, our work suggests the importance of establishing a new framework for reliability evaluation of MBDS devices, which must account for the asymmetric trapping dynamics under bidirectional voltage blocking, as well as the impact of the second gate.

Optically-controlled power devices offer a promising solution for reducing electromagnetic interference and enhancing device synchronization for stacked devices in many applications like grid and renewable energy processing. This work, for the first time, demonstrates the optical control of a 650 V GaN HEMT using two low-power photodiodes (PDs) to achieve ultrafast hard switching. We apply complementary optical signals to two InGaAs PDs in a totem-pole configuration, providing rapid charging and discharging paths for power device. The GaN HEMT is found to be particularly suited for such configuration due to its low input capacitance compared to SiC and Si devices. The design is experimentally validated under a 400 V hard switching condition using a double-pulse test (DPT) setup. At 400 V/ 3 A hard switching, the fall and rise times of 63.2 ns and 64 ns were demonstrated under a 45-mW power consumed on each PD. These results represent the highest switching voltage and switching current reported in optically-controlled GaN devices, as well as the fastest switching speeds reported in all optically-controlled power devices to date. This work highlights the potential of the PD-based optical driving scheme and the optically-controlled GaN HEMTs for emerging power electronics applications.