Modeling and Evaluating the Performance of a Split-Gate T-Shape Channel DM DPDG-TFET Biosensor for Label-Free Detection

Abstract

In this paper, a DM DPDG TFET (Dielectrically modulated Drain pocket Dual gate Tunnel Field Effect Transistor) with an integrated nanocavity intended for biosensing applications is simulated and its performance assessed. The Silvaco Atlas TCAD used to do the simulations. The study compares several metrics for different biomolecules, including SARS COV-2 (Corona virus, K =2.5), Biotin (K =2.63), Protein (K =3.23), MCF-10A (Healthy Cancer cell, K =4.5), Carbohydrates (K =5) and MDA-MB-231 (Breast Cancer cell, K =22). These biomolecules are rendered immobile by a nanocavity is placed near the source end. When biomolecules are immobilized, the dielectric constant (K) of the nanocavities varies, which affects how the electrical properties of the proposed device is modulated. This modulation is tuned to identify the SARS COV-2, Breast cancer cell lines, and etc. To improve performance of the sensor device, the length of the oxide layer and thickness of the nanocavity adjusted in the process of optimization. The proposed Biosensor of its detection method is greatly influenced by the differences in the dielectric characteristics of different cell lines. The sensitivity of the biosensor is assessed in terms of $\Delta $ Ion, $\Delta $ Vth, $\Delta $ gm and $\Delta $ SS. The MDA-MB-231 (K =22) breast cancer cell line is the sample for which the biosensor shows highest sensitivity with $\Delta $ V ${_{\text {th}}} {=} 1.712$ V, $\Delta $ I ${_{\text {on}}} {=} 0.183$ mA/ $\mu $ m, $\Delta $ g ${_{\text {m}}} {=} 0.581$ mA/V- $\mu $ m, and $\Delta $ SS =25.86 mV/decade. The effect of different cavity occupancy by immobilized cell lines is also investigated. Increase in cavity occupancy amplifies the variance in the performance characteristics of the biosensor. The threshold voltage(Vth) sensitivity of the proposed biosensor is compared to that of existing biosensors, it shows advantages in terms of cost-effectiveness and simplicity of manufacturing in addition to increased Ion/Ioff ratio, gm, sensitivity. As a result, the device has potential to use in the identification of SARS COV-2, cancerous cells, etc.