GaN/InGaN double quantum well (DQW) gate structure for GaN-on-Si based normally-off AlGaN/GaN high electron mobility transistors (HEMTs)

Abstract A GaN/InGaN double quantum well (DQW) gate structure was designed on a conventional GaN-on-Si based AlGaN/GaN heterostructure. The electrical characteristics of the devices exhibited a normally-off or E-mode (enhancement-mode) operation with a threshold voltage ( V t h ) of +0.53 V. We achieved a drain current density ( I d ) of 171 mA/mm and a specific on-resistance ( R o n , s p ) of 2.45 m Ω -cm 2 . The leakage current densities of the devices, under the off-state condition, were of the order of 10−7 mA/mm. This DQW gate also prevents electron leakage through the gate, which improves the current gain ( h F E ) significantly. The fabricated normally-off i -DQW HEMTs showed excellent 3-terminal off-state breakdown characteristics ( > 1000 V).