Investigation on threshold voltage of p-channel GaN MOSFETs based on p-GaN/AlGaN/GaN heterostructure* *Project supported by the Key-Area Research and Development Program of Guangdong Province, China (Grant Nos. 2020B010174001 and 2020B010171002), the Ningbo Science and Technology Innovation Program 2025 (Grant No. 2019B10123), and the National Natural Science Foundation of China (Grant No. 62074122).

Abstract

The threshold voltage (V th) 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 Φ 1,p, polarization charge density σ b, and equivalent unite capacitance C oc. It is found that the thinner thickness of p-GaN layer and oxide layer will acquire the more negative threshold voltage V th, and threshold voltage |V th| 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 |V th|. 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 V GS = –12 V and V DS = –10 V.