Channel thickness optimization for ultra thin and 2D chemically doped TFETs

TL;DR

This paper investigates the optimal channel thickness for 2D material-based tunnel FETs, balancing tunneling distance and device performance, using simulations and an analytic model for specific materials.

Contribution

It introduces a new analytic model to determine the optimal channel thickness for different 2D materials, validated by quantum transport simulations.

Findings

Optimal channel thickness varies by material.

The analytic model accurately predicts optimal thickness.

Performance depends on balancing tunneling distance and depletion width.

Abstract

2D material based tunnel FETs are among the most promising candidates for low power electronics applications since they offer ultimate gate control and high current drives that are achievable through small tunneling distances during the device operation. The ideal device is characterized by a minimized tunneling distance. However, devices with the thinnest possible body do not necessarily provide the best performance. For example, reducing the channel thickness increases the depletion width in the source which can be a significant part of the total tunneling distance. Hence, it is important to determine the optimum channel thickness for each channel material individually. In this work, we study the optimum channel thickness for three channel materials: WSe$_{2}$, Black Phosphorus (BP), and InAs using full-band self-consistent quantum transport simulations. To identify the ideal channel thickness for each material at a specific doping density, a new analytic model is proposed and benchmarked against the numerical simulations.