📝 SummarXiv

Abstract

Scaling field-effect transistors (FETs) into the sub-10 nm regime fundamentally alters electronic transport mechanisms, challenging the conventional design rules that have underpinned semiconductor technology for decades. The impact of competing classical and quantum transport on sub-10-nm 2D FET scaling remains poorly understood. In this work, we investigate the transport properties of 2D TMD nanojunctions with channel lengths from 12 down to 3 nm, using first-principles calculations that integrate the nonequilibrium Green function formalism implemented in density functional theory (NEGF-DFT) and an effective gate model. Our simulations reveal a pronounced crossover from semiclassical thermionic emission to quantum tunnelling, governed by two characteristic temperatures:(1) $T_{c}$, denotes the temperature at which the OFF current reaches its minimum, marking the optimal condition for turning off the transistor; (2) $T_{t}$, above which the subthreshold swing saturates at the Boltzmann tyranny scaled by the gate-control efficiency factor. Longer channels enter the classical regime at much lower temperatures, where thermionic emission dominates, and perfect contact with S.S. approaches the Boltzmann Tyranny scaled by the gate controlling efficiency. The shortest 3 nm junction exhibits pronounced quantum tunneling up to 500 K and achieves a subthreshold swing superior to the physical limit of transistors, known as the Boltzmann Tyranny, enabled by the steep energy dependence of the transmission coefficient. This study provides a theoretical prediction of the transition from classical to quantum transport in sub-10 nm 2D TMD transistors, identifying critical temperatures that define the boundary between these regimes and offering key design insights for harnessing quantum and classical hybrid transistor technology.