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

This work presents a new TFET architecture which not only diminishes ambipolar current ( I AMB ) but also shows high on state current ( I ON ), high ratio of I ON to I OFF , and less off-state current ( I OFF ). 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 I AMB 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 ( C gd ), cutoff frequency ( f T ), total gate capacitance ( C gg ), and the intrinsic time delay ( τ ) for both of the devices (proposed and HJ TFETs) has been studied.