Asymmetric Triple-Channel Schottky Barrier FinFET Biosensor for Cardiac Biomarker Detection

Abstract We have designed and simulated a new form of Schottky barrier FinFET, known as an SB-FinFET, that is designed to detect cardiac biomarker proteins without labels. The SB-FinFET uses an asymmetric, triple-channel stacked architecture, with the three channels positioned vertically on top of each other. The SB-FinFET consists of three channels made of silicon carbide (SiC), with nickel silicide (NiSi) Schottky contacts and hafnium oxide (HfO 2 ) insulating material as the gate dielectric to reduce the amount of intrinsic leakage current and improve the efficiency with which electrostatic coupling occurs. The architecture allows for the decoupling of current driving ability from sensing ability because of the difference in doping levels of the channels: the two outer channels have a doping density of 1 x 10 17 cm − 3 and are 4 nm deep, while the central channel has a doping density of 1 x 10 10 cm − 3 and is 1 nm thick. The two outer channels provide a suitable amount of current drive and gain, while the central channel serves as a high-sensitivity transducer that converts the biomarker/protein interaction into an electrical signal. The 3D TCAD simulation results exhibit an I ON /I OFF ratio of approximately 1 x 10 8 with low subthreshold swing for target biomolecules that have dielectric constants within the range of k = 1.5–3.5 (e.g., uricase, streptavidin, and troponin). The performance was further characterized through an analysis of linearity with transconductance (g m ) and through third-order nonlinearity metrics (VIP 3 and IIP 3 ). The SB-FinFET has been compared against other types of devices, including Negative Capacitance FET (NC-FET) and Tunnel FETs (TFETs), for sensitivity and complexities associated with fabrication. The results from these comparisons show that SB-FinFET's performance is similar to the two other device structures previously mentioned, while having a lower complexity and cost to fabricate them. The SB-FinFET is therefore an excellent experimental platform for developing new cardiac diagnostics devices that would allow for rapid diagnosis at or near the site of patient care.