Is accumulation or inversion mode dielectric modulated FET better for label-free biosensing?: A comparative investigation

Abstract

In this paper, we present a comprehensive assessment of dielectric modulated accumulation mode field-effect transistor (AMFET) architecture for label-free biosensing in comparison with inversion mode field-effect transistor (IMFET) architecture. The underlying physics of the AMFET and IMFET biosensors was explored by investigating variation in the conduction band and the electron concentration profile (e−CP) under both ON-state and OFF-state due to charged and neutral bio molecule immobilisation. Subsequently, essential sensitivity parameters are estimated for biosensing. It is observed that the variation in electron concentration profile has a huge impact on the drain current and threshold voltage. Sensitivity evaluation predicts AMFET to have improved ION/IOFF, OFF-current and threshold (VTH) shift. AMFET shows enhanced sensitivity to charged biomolecules over neutral bio molecules. From the investigations done, the AMFET has outperformed at lower bias and fails to predict optimum results at higher bias compared to IMFET. This leaves a choice to use the desired device as per the biasing availability for label-free detection of the biomolecules.