An improved tunnel field-effect transistor with an L-shaped gate and channel

Abstract

An improved tunnel field-effect transistor with an L-shaped gate and channel (LLTFET) is proposed herein. The new structure shows an increased ON-current without any change in the overall area in comparison with state-of-the-art structures. The L-shaped gate extends into the substrate and overlaps with part of the source. An N+ pocket located just below the gate facilities tunneling in both the horizontal and vertical directions, which results in the increased ON-current. Three different models are proposed herein to increase the ON-current with the added advantage of simplified fabrication steps. For one of the proposed models, the ON-current is improved by 63% while the OFF-current is reduced to 12.5% compared with an L-shaped gate TFET (LGTFET) described in literature. An optimum model is also proposed, achieving a subthreshold swing of 21.2 mV/decade at 0.05$$V_{\mathrm{gs}}$$. The simulations are performed using Silvaco ATLAS with the nonlocal band to band tunneling (BTBT) model.