Can Tunnel Transistors Scale Below 10nm?

TL;DR

This paper demonstrates that tunnel FETs can be scaled below 10nm by optimizing bandgap and effective mass, enabling low-voltage operation and small channel lengths with high performance.

Contribution

It introduces a scaling rule for TFETs based on bandgap and effective mass engineering, allowing for sub-10nm channel lengths at low supply voltages.

Findings

Scaling rule of L_{ch}/V_{DD}=30 nm/V for TFETs.

Optimal bandgap around 1.2 eV for low V_{DD}.

Engineered effective mass enhances performance at small scales.

Abstract

The main promise of tunnel FETs (TFETs) is to enable supply voltage ($V_{DD}$) scaling in conjunction with dimension scaling of transistors to reduce power consumption. However, reducing $V_{DD}$ and channel length ($L_{ch}$) typically deteriorates the ON- and OFF-state performance of TFETs, respectively. Accordingly, there is not yet any report of a high perfor]mance TFET with both low V$_{DD}$ ($\sim$0.2V) and small $L_{ch}$ ($\sim$6nm). In this work, it is shown that scaling TFETs in general requires scaling down the bandgap $E_g$ and scaling up the effective mass $m^*$ for high performance. Quantitatively, a channel material with an optimized bandgap ($E_g\sim1.2qV_{DD} [eV]$) and an engineered effective mass ($m*^{-1}\sim40 V_{DD}^{2.5} [m_0^{-1}]$) makes both $V_{DD}$ and $L_{ch}$ scaling feasible with the scaling rule of $L_{ch}/V_{DD}=30~nm/V$ for $L_{ch}$ from 15nm to 6nm and corresponding $V_{DD}$ from 0.5V to 0.2V.