Mechanism of breakdown enhancement in AlGaN/GaN HEMTs using a high-k passivation layer

In this paper, we have investigated the mechanism of breakdown enhancement in AlGaN/GaN HEMTs using a high-k passivation layer. A group of depletion capacitance models are proposed to investigate the breakdown enhancement of the high-k passivation layer. With a passivation layer, the drain-side wall and top of the gate metal would form metal-insulator-semiconductor contacts with GaN-based heterojunction, which is the reason for the modulation of the high-k passivation layer on electric field.