A Vertically Stacked Nanosheet Gate-All-Around FET for Biosensing Application

Cong Li,Yiqi Zhuang,Ru Han,Feichen Liu

doi:10.1109/access.2021.3074906

Cong Li, Yiqi Zhuang + Show 2 more

Open Access

https://doi.org/10.1109/access.2021.3074906

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Abstract

In this paper, a vertically stacked nanosheet gate-all-around field-effect transistor (GAA-NSFET) as a label-free biosensor has been proposed and investigated. The influences of different biomolecules on the biosensor’s electrical properties are analyzed, and the proposed biosensor exhibits good sensitivity for both neutral and charged biomolecules. Furthermore, a deep sensitivity analysis is performed to evaluate the sensing ability of biosensors with different channel structures. The sensitivity variation of biosensors is analyzed in terms of subthreshold swing ( $SS $ ), threshold voltage ( $V_{\text {th}}$ ), and current switching ratio ( $I_{\text {on}} / I_{\text {off}}$ ). The results show that GAA-NSFET-based biosensor obtains the best sensitivity compared with other biosensors (including nanowire FET-based biosensor and vertically stacked nanowire FET-based biosensor) due to its larger channel width and multi-channels. Also, the influences of filling position on sensitivity are analyzed in various cases for the proposed biosensor. Its sensitivity depends on the filling amounts of biomolecules instead of the filling position. Finally, a status map is presented, which plots the sensitivity of some important works in biosensing application along with the sensitivity of the proposed biosensor, and GAA-NSFET-based biosensor is more sensitive compared with those works in terms of $I_{\text {on}}/I_{\text {off}}$ sensitivity.

Highlights

Field-effect transistor (FET) based biosensors have drawn increasing attention in the field of medical and food security for label-free detection of biomolecules [1], [2]
The device characteristic shows an evident variation with different target biomolecules
A comparative sensitivity analysis of GAA-NSFET-based biosensor, VS-NWFET-based biosensor, and conventional NWFET-based biosensor is discussed, which shows that the proposed GAA nanosheet (GAA-NS)-based biosensor is more sensitive than the other two biosensors for both neutral and charged biomolecules

Summary

INTRODUCTION

Field-effect transistor (FET) based biosensors have drawn increasing attention in the field of medical and food security for label-free detection of biomolecules [1], [2]. As transistors shrink to the nanometer scale, traditional planar FET devices will suffer severe short-channel effects, resulting in increased power consumption and decreased sensitivity of the DMFET-based biosensors [11]. C. Li et al.: Vertically Stacked Nanosheet GAA FET for Biosensing Application the location of biomolecules is very critical for TFET-based biosensors. We combine this GAA-NS structure with the dielectrically modulated (DM) method to obtain a new GAA-NSFET-based biosensor. In this work, partial high-κ dielectrics are deposited near the drain spacer to achieve lower power dissipation

RESULT

CONCLUSION