Numerical Simulation of Hetero Dielectric Trench Gate JAM Gate-All-Around FET (HDTG-JAM-GAAFET) for Label Free Biosensing Applications

Abstract

The label free detection of various biomolecules associated with different diseases has been proposed in this manuscript using a novel biosensor design named as the Hetero Dielectric Trench Gate Junctionless Accumulation Mode Gate-All-Around FET (HDTG-JAM-GAAFET). This biosensor employs a silicon cylindrical Gate All Around FET which operates in Junctionless Accumulation Mode (JAM) and has a hetero dielectric layer comprised of SiO2 and HfO2. The cylindrical gate structure’s metal gate is trenched into the Hafnium oxide dielectric layer, which provides the gate with enhanced control over the surface characteristics of the channel. A Trench Gate architecture in a hetero dielectric Gate All Around FET is emulated for the biosensing for the first time. The HDTG-JAM-GAAFET has been compared to Normal Gate JAM Gate-All-Around FET (NG-JAM-GAAFET) biosensors immobilizing a variety of neutral biomolecules and biomolecules having a range of positive and negative charges. The effect of biomolecules on HDTG-JAM-GAAFET biosensor’s output properties, including surface potential, electron concentration, threshold voltage drift (ΔVTH), subthreshold leakage current (IOFF), subthreshold slope (SS), switching ratio (ION/IOFF), ION current sensitivity, transconductance (gm), output conductance (gd), channel resistance (Rch) and intrinsic gain ( AVint ) has been studied. For instance, HDTG-JAM-GAAFET biosensor has drain ON-current sensitivity (SION) which is 67.68% greater for gelatin biomolecules, 69.4% higher for positive biomolecules, and 8% higher for negative biomolecules bound in the nanogap cavity than that of a Normal Gate JAM Gate-All-Around FET. The proposed device exhibits exceptional performance characteristics and it can effectively identify specific biomolecules to diagnose many diseases, such as breast cancer, lung cancer, and numerous viral infections, using their respective biomarkers.