600 V High-Performance AlGaN/GaN HEMTs with AlN/SiN_x Passivation

摘要

The current collapse suppression capability after high OFF-state drain bias stress of a newly developed passivation technique using an AlN/SiN_x stack structure without multiple field plates in high-voltage AlGaN/GaN HEMTs is demonstrated in this work. The increase of dynamic RON is suppressed to only 58% of the static RON during OFF-ON switching after a high drain bias stress of 650 V. The AlN/SiNx-passivated HEMTs deliver a high ON/OFF current ratio of more than eight orders of magnitude. The maximum drain current reaches 900 mA/mm, while the drain leakage current remains below 0.7μA/mm at VDS up to 600 V with V_(GS) = -5 V. Owing to the low OFF-state leakage, a steep subthreshold slope (SS) of 63 mV/dec was simultaneously achieved. The breakdown voltage of the AlN/SiN_x-passivated HEMTs with a specific ON-resistance of 1.3 MΩ·cm~2 was measured to be 632 V at a drain leakage current of 1μA/mm, resulting in a high figure of merit (FOM = BV~2/R_(on, sp)) of 310 MW·cm~2, which is highly desirable for high voltage power switching applications.