Dielectrically Modulated Drain Pocket VTFET Biosensor Based on Transconductance Generation Factor g m /I D

Biosensors play a critical role in the detection of diseases, pollutants, and environmental contaminants. Key performance parameters of biosensors include high sensitivity, linearity, fast response, and low detection limits. This manuscript presents a Ge source VTFET-based biosensor that leverages the subthreshold region of its transfer characteristics to support ultra-low voltage operation while enhancing these critical performance parameters. The study utilizes the transconductance generation factor (gm/ID) as the sensing metric. The VTFET architecture is first optimized to form a Drain Pocket VTFET (DP VTFET) through drain pocket engineering, channel undercut length adjustment, and oxide thickness tuning, aiming to enhance ON-state performance and subthreshold behavior. The optimization mainly focuses on reducing the subthreshold swing (SS) of the VTFET to maximize the gm/IDin the subthreshold region. Using the optimized design, a Dielectrically Modulated Drain Pocket VTFET (DMDP VTFET) biosensor is developed for the detection of various biomarkers, including healthy (MCF-10A) and cancerous (HS578t) breast cell lines, proteins Zein and Keratin, and the agrochemical Pyridine. Sensitivity and linearity analyses are conducted using the gm/IDsensing metric, considering both positive and negative polarity of the biomarkers. Noise performance is also evaluated, revealing a high signal-to-noise ratio (SNR) of 1.01 × 104V−1for the HS578t biomarker, resulting in a limit of detection (LOD) as low as three elementary charges. The proposed DMDP VTFET biosensor offers a promising solution for label-free, energy-efficient, and highly sensitive biomolecular detection at a low drain voltage of 0.4 V.