Polarization-enhanced sub-5 nm Janus MoSiGeN4 FET for high-performance and low-power applications

Achieving ultra-short channel field-effect transistors (FETs) that cater to both high-performance (HP) and low-power (LP) applications simultaneously is an unremitting pursuit in the field. Herein, employing first-principles calculations, we investigate the performance of sub-5 nm FETs based on the Janus MoSiGeN₄ material and reveal the role of intrinsic out-of-plane electric polarization. We demonstrate that the synergistic effect of the intrinsic polarization field and the external electric field enhances the performance of Janus MoSiGeN₄ FETs over MoSi₂N₄ and MoGe₂N₄ FETs. Our simulations show that a 3 nm gate-length cold-source Janus MoSiGeN₄ FET, utilizing LaOCl as the dielectric material and an appropriate underlap structure, fulfills the HP and LP standards set by the International Technology Roadmap for Semiconductors (ITRS), with a subthreshold swing approaching the Boltzmann tyranny of 60 mV/dec. Notably, the optimized 1 nm gate-length MoSiGeN₄ FET achieves an on-state current of 990 μΑ/μm (HP) and 690 μΑ/μm (LP), surpassing other theoretical two-dimensional FETs at the same gate length. Taking the defect effects into account, the MoSiGeN₄ FET maintains a high on-state current that surpasses the ITRS for HP and LP standards. Our results provide a promising approach for designing ultra-short channel FETs suitable for both HP and LP applications.