Layer Dependence and Point Defect for Sub-5 nm 2D Hydrogenated GaN Transistors

Silicon-based devices face intrinsic physical limitations in high-power and high-frequency applications due to their narrow bandgap and low breakdown strength. As an emerging postsilicon semiconductor, gallium nitride (GaN) offers significant advantages for next-generation high power electronics owing to its wide bandgap, high breakdown field strength, and outstanding radiation tolerance. In this work, we investigate the layer dependence and point defect of sub-5 nm hydrogenated GaN (H-GaN) transistors by ab-intio quantum transport simulation. The n-type H-GaN transistors with monolayer (ML), bilayer (BL), and trilayer (TL) channels all meet the ITRS on-state current targets. The ML devices yield the optimal performance with an I on of 2694 μA/μm, which exceeds those of the BL (2536 μA/μm) and TL (1974 μA/μm). Furthermore, atomic vacancy defects critically impact transport: for n-type ML devices, single N and Ga vacancies reduce I on from 2694 to 1242 and 5.72 μA/μm, respectively. Our work provides theoretical guidance for the miniaturization of future low-dimensional high-power GaN electronic devices.