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The threshold voltage (Vth) of the p-channel metal–oxide–semiconductor field-effect transistors (MOSFETs) is investigated via Silvaco-Atlas simulations. The main factors which influence the threshold voltage of p-channel GaN MOSFETs are barrier height Φ1,p, polarization charge density σb, and equivalent unite capacitance Coc. It is found that the thinner thickness of p-GaN layer and oxide layer will acquire the more negative threshold voltage Vth, and threshold voltage |Vth| increases with the reduction in p-GaN doping concentration and the work-function of gate metal. Meanwhile, the increase in gate dielectric relative permittivity may cause the increase in threshold voltage |Vth|. Additionally, the parameter influencing output current most is the p-GaN doping concentration, and the maximum current density is 9.5 mA/mm with p-type doping concentration of 9.5 × 1016 cm−3 at VGS = –12 V and VDS = –10 V. [ABSTRACT FROM AUTHOR]

In this paper, we present the combination of drain field plate (FP) and Schottky drain to improve the reverse blocking capability, and investigate the reverse blocking enhancement of drain FP in Schottky-drain AlGaN/GaN high-electron mobility transistors (HEMTs). Drain FP and gate FP were employed in a two-dimensional simulation to improve the reverse blocking voltage (VRB) and the forward blocking voltage (VFB). The drain-FP length, the gate-FP length and the passivation layer thickness were optimized. VRB and VFB were improved from −67 V and 134 V to −653 V and 868 V respectively after optimization. Simulation results suggest that the combination of drain FP and Schottky drain can enhance the reverse blocking capability significantly. [ABSTRACT FROM AUTHOR]