Metal Drain Double-Gate Tunnel Field Effect Transistor with Underlap: Design and Simulation

Abstract

In this paper, we propose and simulate a novel double gate tunnel field effect transistor (DG-TFET) employing a metallic drain and a gate-drain underlap. The use of a metallic drain and an underlap results in complete ambipolar suppression in the proposed TFET. A 2D calibrated simulation studies have revealed that ambipolar current suppression of ~ 5 orders, without affecting the on-state current of the device, when the gate voltage is varied between 1 V and -1 V, is achieved in the proposed device in comparison to the conventional DG-TFET. The complete ambipolar reduction is attributed to the reduced band-to-band-tunneling (BTBT) rate because of the Schottky barrier formation at the channel/drain interface. Further, the use of gate/drain underlap suppresses the ambipolarity completely in the proposed device in comparison to the conventional one. An ON current (ION) and OFF current (IOFF) ratio (ION/IOFF) of ~ 1012 with a subthreshold slope (SS) of 63 mV/decade is achieved in the proposed device. Further, the effect of change of various parameters on the performance of the proposed device has been thoroughly studied. It has been observed that the performance can be optimized further by using the optimum value of these parameters. A process flow for the fabrication of the proposed device has also been given.