Quantum Transport Study of 5.1 nm P-Type Field-Effect Transistors Based on WSe2/BoroΔ and WSe2/NbS2 for High-Performance CMOS Logic Applications

Abstract

In this study, the transport performance of two p-type field-effect transistors (FETs) based on monolayer WSe2 with a 5.1 nm gate length is systematically investigated using density functional theory and quantum transport simulations. BoroΔ and NbS2, which have relatively high work functions, are adopted as the source electrodes in the two devices, while a p-doped channel extension region is used as the drain electrode. Both devices exhibit small p-type Schottky barriers at the vertical and lateral interfaces. By introducing an underlap (UL) structure and a high-κ dielectric layer, the WSe2/BoroΔ FET achieves an on-state current of 2322 μA/μm at κ = 20, whereas the WSe2/NbS2 FET reaches 2344 μA/μm at UL = 1 nm and κ = 20. Further p-type doping of the cold metal NbS2 strengthens its filtering effect on high-energy holes, enabling the WSe2/NbS2 FET to achieve an on-state current of 2089 μA/μm and a subthreshold swing as low as 55 mV/dec at UL = 2 nm and κ = 20. This work provides theoretical guidance for the design of high-performance steep-slope p-type transistors toward next-generation complementary metal-oxide-semiconductor (CMOS) logic applications.