Enhanced on-state current and suppressed ambipolarity in germanium-source dual vertical-channel TFET

Abstract

Abstract In this paper, we provide a solution for the main disadvantages of tunnel field effect transistors (TFETs) by presenting a germanium-source dual vertical-channel TFET. Our device is composed of two Ge/Si tunneling junctions in which charge carriers tunnel perpendicular to the gate, and two n+ epi-Si layers which serve as two vertical conduction channels. Owing to the recessed gate architecture and overlap of the gate with source and drain regions, we remarkably increase the on-state current and suppress the ambipolar conduction. A calibrated Atlas device simulator is employed to investigate the device performance, and the simulation results show a dramatic drive current value of about 300 µA µm−1 and on-state to off-state current ratio of about 7 × 109. Moreover, our TFET yields a minimum subthreshold swing of 5.9 mV dec−1, and a sub 60 mV dec−1 subthreshold swing over six decades of drain current at 0.5 V operating voltage.