A high aspect ratio Fin-Ion Sensitive Field Effect Transistor: compromises towards better electrochemical bio-sensing

TL;DR

This paper introduces a high aspect ratio FinFET biosensor that enhances electrochemical sensing by improving reproducibility, reducing noise, and maintaining fast response times, addressing key limitations of nanosensors.

Contribution

It proposes a novel high aspect ratio FinFET design for biosensing, demonstrating improved signal linearity and reliability over traditional nanosensors.

Findings

Higher aspect ratio FinFETs show increased signal and linearity.

The device's response to pH changes fits the Nernst-Poisson model.

Optimized geometry enhances detection limits and reproducibility.

Abstract

The development of next generation medicines demand more sensitive and reliable label free sensing able to cope with increasing needs of multiplexing and shorter times to results. Field effect transistor-based biosensors emerge as one of the main possible technologies to cover the existing gap. The general trend for the sensors has been miniaturisation with the expectation of improving sensitivity and response time, but presenting issues with reproducibility and noise level. Here we propose a Fin-Field Effect Transistor (FinFET) with a high heigth to width aspect ratio for electrochemical biosensing solving the issue of nanosensors in terms of reproducibility and noise, while keeping the fast response time. We fabricated different devices and characterised their performance with their response to the pH changes that fitted to a Nernst-Poisson model. The experimental data were compared with simulations of devices with different aspect ratio, stablishing an advantage in total signal and linearity for the FinFETs with higher aspect ratio. In addition, these FinFETs promise the optimisation of reliability and efficiency in terms of limits of detection, for which the interplay of the size and geometry of the sensor with the diffusion of the analytes plays a pivotal role.