E-mode p-GaN Gate HEMT with p-FET Bridge for Higher V TH and Enhanced V TH Stability

a novel p-GaN gate topology is proposed to inherently increase threshold voltage (V TH ) and enhance V TH stability. The gate consists of a conventional Schottky-type p-GaN gate and a normally-on p-channel FET bridge connecting source and gate. By modulating the V TH of the p-channel FET, a wide-range positive V TH from 3.6 V to 8.2 V can be achieved without subthreshold voltage degradation. Owing to the well-grounded p-GaN through the normally-on p-FET channel, a stable V TH is also achieved without sacrificing the low gate leakage and large gate swing enabled by the Schottky gate metal/p-GaN contact.