Dielectric Modulated Double Gate Hetero Dielectric TFET (DM-DGH-TFET) Biosensors: Gate Misalignment Analysis on Sensitivity

In this article, we have investigated the Gate misalignment effects on the performance of the Double gate hetero dielectric TFET(DGH-TFET) biosensor device in terms of subthreshold swing(SS), ON-current (I$_{\mathbf{on}}$), OFF Current (I$_{\mathbf{off}}$), Threshold voltage (Vth) and the ratio of ON-current (Ion) to the OF-current (I$_{\mathbf{on}} {/\mathbf{I}}_{\mathbf{off}}$). For the first time, we have thoroughly investigated the misalignment of gate electrodes effect on the sensitivity of the double gate TFET based biosensor where actually considered the symmetric gate structure with no deviation in the gate alignment, however practically which is not possible. With due respect to the investigation carried in this work along with the sensitivity analysis, it observed that position and the alignment of both top and bottom gate show significant impact on the sensitivity of the biosensor. The misalignment of the double gate is executed by altering the position of the top gate in overlapped state and underlapped state concerning the bottom gate of the proposed double gate TFET biosensor. The underlapped gate structure degrades the performance device compared to the symmetric aligned gate structure, but the overlapped gate structure improves the device’s overall performance. The investigation is carried by taking the misalignment effect in the range of 10 nm in both overlapped and underlapped cases. The underlapped alignment gate structure falls of the subthreshold sensitivity by 30%, where the overlapped gate structure become the advantage for shoot up the sensitivity of the doublet gate hetero dielectric TFET biosensor by 25% and the underlapped gate structure improves the threshold voltage sensitivity 45% on an average.