Design and Realization of GaN Trench Junction-Barrier-Schottky-Diodes

We present the design principle and experimental demonstrations of GaN trench junction barrier-Schottky-diodes (trench JBSDs), where the Schottky contact within the patterned trenches is at the same plane as the adjacent p-n junctions. Assisted by the TCAD simulations, the leakage current reduction mechanism is identified as the reduced surface field (RESURF) effect due to the barrier-height difference between the p-n junction and Schottky junction. Design space for the width of stripe-shaped trenches is found to be <0.5 mu pm for a drift layer doping level of 10(15)similar to 10(16) cm(-3), while for circular trenches, the size requirement is relaxed. In the fabricated devices with 1-4 mu m diameter circular trenches, about 20 times reduction in the reverse leakage is observed with a characteristic shift in the turn-on voltage, which are signatures of the trench JBSD with desired RESURF. The experimental observations are in excellent agreement with the simulation results. This JBSD design shows promising potential in further improving the performance of Schottky-based GaN power devices without the need for ion-implantation or material regrowth.