Proposal and evaluation of Mg2Si-based vertical tunnel field effect transistor for enhanced performance

Abstract

This work investigates the performance of silicon-on-insulator (SOI) based vertical heterojunction tunnel FET with magnesium silicide (Mg2Si) as source material (Mg2Si-VTFET) with silicon-based counterpart (Si-VTFET). The investigation utilizes SILVACO TCAD tool to analyse various metrics including electrical characteristics, radio-frequency performance, linearity, and distortion. Incorporation of low bandgap material at source forms hetero-junction at source-channel interface, thereby reducing the tunneling path and enhancing the tunneling rate of charge carriers. ON-state current (ION) and current switching ratio (ION/IOFF) for Mg2Si-VTFET improves by factor of approximately ∼ 105 and 102 times. Mg2Si-VTFET outperforms Si-VTFET in terms of ION current for low biasing voltages, transconductance (gm), gain-bandwidth-product (GBP), cut-off frequency (fT) and transit-time. However, Mg2Si-VTFET has better linearity and reduced distortions in terms of VIP2 and HD2 metrics. HD2 suppresses by 53.8 % for Mg2Si-VTFET over Si-VTFET. This suggests that Mg2Si-VTFET is better suited for applications requiring low distortion, such as in audio amplifiers or communication systems. Therefore, Mg2Si-VTFET shows strong candidacy over Si based counterpart for low power circuits.