Study and analysis of the effects of trap assisted tunneling on the sensing performance of InAs/Si hetero juncture TFET based biosensor

Abstract

This article investigates the impact of trap related non-idealities on the sensing characteristics of Indium Arsenide/Silicon (InAs/Si) heterojuncture tunnel field-effect transistor (TFET) with dual metal stacked dielectric. Presence of straddling band alignment improves the tunneling probability across InAs/Si junction of the present device thereby boosting its sensing ability. Two cavities carved in the gate dielectric across the source side act as the sensing site for the detection of biomolecules. These biomolecules are immobilized within the implanted cavity to induce the drain current. Extensive simulation is carried out using Silvaco ATLAS device simulator activating trap assisted tunneling model to capture the realistic environment of biosensor in contrast to ideal condition for better reliability analysis. The study shows that trap assisted tunneling effectively modulates the important sensitivity metrics of the biosensor including ON current sensitivity, sub-threshold sensitivity with significant impact on Id-VGS characteristics, subthreshold slope profiles and Ion/Ioff ratio and hence cannot be neglected for accurate estimation of sensitivity for real time applications.