Sky-FET: A Selective Area Regrown GaN Power Device with Enhanced Breakdown Voltage

This letter reports a novel GaN power device architecture, named the Sky-FET, which surpasses the conventional breakdown limits of lateral GaN power devices through the integration of vertical and lateral conduction paths enabled by selective area regrowth. A regrown n-GaN layer is incorporated beneath the drain region, effectively decoupling the trade-off between breakdown voltage (BV) and gate-to-drain spacing (L_GD). With the substrate grounded, experimental results show a significant increase in BV from 518 V to 761 V at L_GD = 4.5 μm. TCAD simulations and high-voltage C–V measurements further reveal that the regrown layer reshapes the lateral electric field distribution, substantially suppressing the peak field near the gate edge. These findings demonstrate the Sky-FET as a compelling candidate for next-generation GaN power devices with enhanced performance and scalability.