Robustness to ambipolarity and improvement to HF FOMs of dual-stacked-gate dielectrics underlap heterojunction TFETs

Abstract

This work presents a new TFET architecture which not only diminishes ambipolar current (IAMB) but also shows high on state current (ION), high ratio of ION to IOFF, and less off-state current (IOFF). Initially, to show the effects on ambipolarity and on- and off-state current, a comparative analysis of transfer characteristics among the proposed, conventional, and the heterojunction (HJ) TFET has been done. The effects of different gate material work functions and gate oxide thicknesses on IAMB for the proposed TFET and the HJ TFET with no underlap are examined. Further, to analyze the effect of ambipolarity in the high-frequency figure of merit (FOM), a comparative analysis on RF parameters such as gate–drain capacitance (Cgd), cutoff frequency (fT), total gate capacitance (Cgg), and the intrinsic time delay (τ) for both of the devices (proposed and HJ TFETs) has been studied.