Investigation on threshold voltage of p-channel GaN MOSFETs based on p-GaN/AlGaN/GaN heterostructure.

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. [ABSTRACT FROM AUTHOR]