Ab-initio-NEGF Fundamental Roadmap for Carbon-Nanotube and Two-Dimensional-Material MOSFETs at the Scaling and VDD Limit

TL;DR

This study uses advanced quantum mechanical simulations to benchmark the scaling limits of carbon nanotube and 2D material MOSFETs, revealing their potential for ultra-scaled transistors at low voltages.

Contribution

It provides a comprehensive ab-initio NEGF analysis comparing CNT, MoS2, and HfS2 transistors, identifying their optimal scaling regimes and performance limits.

Findings

CNT-FETs achieve highest drive current at sub 1.3 nm diameters and 9 nm channel length.

HfS2 nanosheets outperform others below 9 nm channel length.

Potential for scaling down to 5 nm with reduced VDD.

Abstract

Using accurate Hybrid-Functional DFT coupled with the Non-Equilibrium Green's function (NEGF) formalism, we explore and benchmark the fundamental scaling limits of CNT-FETs against Si and 2D-material MoS$_2$ and HfS$_2$ Nanosheets, highlighting their potential for gate length (L) and supply voltage (VDD) scaling down to 5 nm and to 0.5 V, respectively. The highest drive current is achieved by CNT-FETs with sub 1.3 nm diameters down to $L = 9$ nm and using VDD in the 0.45-0.5V range. Below $L = 9$ nm, however, the HfS$_2$ NS offers the best drive and could further scale down to $L = 5$ nm with a reduced VDD of 0.5 V.