Dielectric Modulated Charge Plasma-Based Label Free Detection of Biomolecules in Dual Metal DG TFET Biosensors

Abstract

In this article, we present dielectric modulation-based label free detection of biomolecules at a cavity under gate metal located near the tunneling junction of charge plasma based dual metal-double gate tunnel FET (CP-DM DGTFET). The biomolecules that settle down in the cavity act as dielectric above the tunneling junction and cause drain current to increase/ decrease. To eliminate the short channel impact and to enhance ION/IOFF ratio without compromising any other device features, dual metal gate architecture with laterally split dielectric is used. The biosensor is capable of recognizing neutral, positive, and negative charges with the highest drain current sensitivity of 2.9× 109 Ccm-2 and highest ION/IOFF ratio of 9.02× 10 11 for biomolecule gelatin with dielectric constant k =12. This work explores the effectiveness of charge-plasma based DM DGTFET for detection of biomolecules such as gelatin (k =12), keratin (k =8), bacteriophage T7 (k =6.3), and APTES (k =3.57) with varied charge distribution at various biasing. The drain current sensitivity, subthreshold slope, drain current, ON/OFF current ratio are computed for various biomolecules and their variations with respect to cavity length, biomolecule charge, etc. are used to detect unknown biomolecules. Finally, RF analysis such as gain bandwidth product, cut-off frequency, transit time, and linearity/selectivity of biosensors are incorporated. The device shows better linearity and less distortion for high -k biomolecules. The results of our studies are reproducible for repeated computed analysis.