Analytical characterization of a label free Si/InAs hetero-interfaced cylindrical BioFETD for biosensing applications

Abstract

This paper investigates the applicability of an Indium Arsenide (InAs) channel-based cylindrical BioFETD for label-free biosensing applications. The adoption of InAs as an alternative channel material in the BioFETD has revealed a 153.38 % and 179.23 % enhancement in sensitivity for Streptavidin and Gelatin detection compared to its conventional counterpart. The investigation into its sensitivity is bolstered by the consideration of multiple metrics, thereby enhancing the reliability of the conclusions drawn. Temperature variations and practical constraints on sensitivity metrics have been taken into account, providing a comprehensive perspective. To establish a benchmark for comparison, the proposed biosensor undergoes evaluation against existing literature, particularly focusing on their sensitivity to confirm their effectiveness. Furthermore, the proposed BioFETD demonstrates notable improvements, with a 139.942 mV (∼122 %) increase in threshold voltage sensitivity over its junctionless variant for Gelatin. Biomolecules localized inside the oxide layer within the embedded cavity affects various electrostatic properties across the device channel, including drain current, surface potential, electric field and threshold voltage. A compact analytical model, based on fundamental physics, has been proposed and shows excellent agreement with the obtained simulated results. The 2D Poisson equation accurately models these properties, with changes in drain current and threshold voltage serving as prime indicators in biomolecule detection. The obtained results make the Si/InAs interfaced BioFETD a perfect candidate for ultra-sensitive detectors.