Layered boron nitride enabling high-performance AlGaN/GaN high electron mobility transistor

The authors proposed a novel α-BN/h-BN dual-layered dielectric to fabricate AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT). In contrast to the Schottky-HEMT, the gate leakage current was suppressed by more than 6 orders of magnitude at forward voltage of 5V. An atomically smooth interface and low interface state density were obtained, benefiting from the quasi-zero lattice mismatch and the passivation effect of α-BN on AlGaN. Electrical analyses demonstrated that boosted gate drive capability, enhanced output current, and high field effect mobility were realized with inserted BN. The electrical breakdown behaviors of BN were investigated with regard to Frenkel-Poole emission mechanism and Fowler-Nordheim tunneling theory for the low and high electric field regime, respectively. This work rendered BN as a perfect candidate for dielectric insulator used in field-effect transistors.