Intrinsic subthermionic capabilities and high performance of easy-to-fabricate monolayer metal dihalide MOSFETs

TL;DR

This paper proposes a simplified design for steep-slope MOSFETs using monolayer transition metal dihalides, demonstrating high performance and subthermionic operation through quantum transport simulations, with potential for advanced nanoscale electronics.

Contribution

The study introduces a novel, fabrication-friendly monolayer MOSFET design that achieves subthermionic switching without complex heterostructures or tunneling barriers, validated by quantum simulations.

Findings

Achieves subthermionic subthreshold swing up to 5 nm channel length

Demonstrates high current levels without tunneling barriers

Shows robustness against electron-phonon thermalization effects

Abstract

We investigate the design of steep-slope metal-oxide-semiconductor field-effect transistors (MOSFETs) exploiting monolayers of transition metal dihalides as channel materials. With respect to other previously proposed steep-slope transistors, these devices require simplified manufacturing processes, as no confinement of the 2D material is needed, nor any tunneling heterojunction or ferroelectric gate insulators, and only n- or p-type contacts are demanded. We demonstrate their operation by studying an implementation based on monolayer CrI$_2$ through quantum transport simulations. We show that the subthermionic capabilities of the device originate from a cold-source effect, intrinsically driven by the shape of the band structure of the 2D material and robust against the effects of thermalization induced by the electron-phonon interactions. Due to the absence of a tunneling barrier when the device is switched on, current levels can be achieved that are typically out of reach for tunnel FETs. The device also exhibits excellent scaling properties, maintaining a subthermionic subthreshold swing (SS) up to channel lengths as short as 5 nm.