摘要
This paper presents the design strategies and comprehensive characterization of 650-V rating monolithic bidirectional GaN HEMTs, designed for high-efficiency Vienna converters. To address the critical trade-off between breakdown robustness and switching losses, a systematic optimization of the field plate geometry was conducted. The optimized device demonstrates a robust blocking capability up to 650 V with an ultra-low leakage current density of < 0.04 μA/mm at 125 ℃, and achieves a significantly reduced output capacitance and storage energy. High-voltage step-stress tests up to 1000 V confirmed immunity to off-state stress-induced charge trapping and robust blocking behavior. Furthermore, dynamic switching characterization at 100 kHz was performed to assess both hard-switching and soft-switching stresses in the Vienna rectifier. Although an increase in dynamic on-resistance (R on,dyn ) was observed under dynamic stress, the device maintained stable on-state conduction without exhibiting any signs of R on,dyn instability. By leveraging established R on,dyn enhancement strategies developed for unidirectional p-GaN HEMTs, the on-state performance and stability can be further optimized for long-term reliability. In addition, a dual-side blocking (DSB) gate-control scheme is evaluated, showing that dual-gate biasing can be used to further reduce effective output charge and stored energy, providing an extra knob for efficiency optimization.