Doping profile engineered triple heterojunction TFETs with 12 nm body thickness

TL;DR

This paper improves triple heterojunction TFETs with 12 nm body thickness by engineering doping profiles, resulting in significantly better sub-threshold swing and ON-current, using advanced quantum transport simulations.

Contribution

The study introduces a doping profile engineering approach to enhance THJ-TFET performance, supported by sophisticated quantum transport simulations.

Findings

Sub-threshold swing improved to 40 mV/dec

ON-current increased to 325 μA/μm at VGS=0.3 V

Quantum transport simulations validated the design improvements

Abstract

Triple heterojunction (THJ) TFETs have been proposed to resolve the low ON-current challenge of TFETs. However, the design space for THJ-TFETs is limited by fabrication challenges with respect to device dimensions and material interfaces. This work shows that the original THJ-TFET design with 12 nm body thickness has poor performance, because its sub-threshold swing is 50 mV/dec and the ON-current is only 6 $\mu A/\mu m$. To improve the performance, the doping profile of THJ-TFET is engineered to boost the resonant tunneling efficiency. The proposed THJ-TFET design shows a sub-threshold swing of 40 mV/dec over four orders of drain current and an ON-current of 325 uA/um with VGS = 0.3 V. Since THJ-TFETs have multiple quantum wells and material interfaces in the tunneling junction, quantum transport simulations in such devices are complicated. State-of-the-art mode-space quantum transport simulation, including the effect of thermalization and scattering, is employed in this work to optimize THJ-TFET design.