Switching Mechanism and the Scalability of vertical-TFETs

TL;DR

This paper investigates vertical TMD-based TFETs using atomistic simulations, revealing a unique switching mechanism, the importance of the extension region for off-state control, and their potential for low-power electronics due to negative capacitance.

Contribution

It uncovers the distinct switching mechanism of v-TFETs and highlights the critical role of the extension region in their scalability and performance.

Findings

Extension region is critical for turning off v-TFETs.

v-TFETs exhibit negative capacitance due to charge distribution.

v-TFETs show promising energy-delay performance for low-power applications.

Abstract

In this work, vertical tunnel field-effect transistors (v-TFETs) based on vertically stacked heretojunctions from 2D transition metal dichalcogenide (TMD) materials are studied by atomistic quantum transport simulations. The switching mechanism of v-TFET is found to be different from previous predictions. As a consequence of this switching mechanism, the extension region, where the materials are not stacked over is found to be critical for turning off the v-TFET. This extension region makes the scaling of v-TFETs challenging. In addition, due to the presence of both positive and negative charges inside the channel, v-TFETs also exhibit negative capacitance. As a result, v-TFETs have good energy-delay products and are one of the promising candidates for low power applications.