Analysis and evaluation of Si(1-x) Ge(x) pocket on sensitivity of a dual-material double-gate dopingless tunnel FET label-free biosensor

Abstract

This work reports a sensitivity analysis for a dual-material double-gate dopingless Tunnel FET (DM-DG-DLTFET) biosensor carrying a Si(1-x) Ge(x) pocket for improved performance of an overall device. The biomolecules are immobilized in a cavity suitable for small-sized biomolecules detection and the performance of the device is investigated by calculating the electrical properties altered due to the dielectric modulation caused by presence and absence of biomolecules by commercially available ATLASTM tool. The Si(1-x) Ge(x) pocket placed under the cavity at source-channel interface helps to attain better on-current which is usually less in case of other reported structures of Tunnel FETs. The variation in the composition of Ge is observed to obtain enhanced sensitivity. The device is studied for threshold voltage sensitivity of neutral as well as charged biomolecules and the nature of the present biomolecule is also determined using the transconductance-to-current ratio (gm/Ids) which can also be considered as a sensing metric. The optimized device design has been proposed keeping track of the electrical and physical trade-offs. Our results show a maximum of 539.5 mV shift in the threshold voltage when dielectric constant (K) of the neutral biomolecule is varied from 1 to 12 which makes our device evidently an efficient candidate for label-free biosensing application.