Demonstration of a Vertically Stacked Junctionless Forksheet as Dielectric Modulated Biosensor

In this paper, we demonstrated the performance metrics of a Junctionless vertically stacked Forksheet FET for biosensing applications. Through the use of well-calibrated TCAD models, the N-and P-side of a Forksheet FET is designed with a cavity region where the presence/absence of the biomolecule is sensed using a permittivity modulation approach. The label-free electrical detection of different biomolecules, including streptavidin (K=2.1), biotin (K=2.63), APTES (K=3.57), and keratin (K=8) is obtained by analyzing the variations in threshold voltage, OFF current, and the ION/IOFF ratio as sensing performance metrics. The proposed Junctionless sensor exhibits superior electrical characteristics and sensitivity at lower metal gate work functions compared to other available Junctionless devices operating at higher metal gate work functions. Thus, the study underscores the potential of the proposed Junctionless Forksheet FET for efficient and accurate biosensing applications.

I. Introduction

In the modern era of ultra-high-scale integration, the semiconductor industry faces several challenges due to the increasing short-channel effects (SCEs) in nanoscale FET devices. The scaling of CMOS transistors has been continually advancing to achieve high-speed operation and high packing density in modern integrated circuits [1]. As transistor scaling progresses towards smaller technology nodes, several proposed devices aim to meet the performance and scaling requirements of these nodes. Nanosheet [2] - [3], Complementary FET (CFET), and Forksheet [4]–[6] are among the available options.