Dielectric modulated triangular gate FinFET biosensor with analytical modeling and TCAD based performance evaluation

Alzheimer’s Disease (AD) is a leading neurological disorder and a major cause of dementia in older adults, with incidence rising in aging populations. Amyloid-β (Aβ) peptides and tau proteins are widely recognized as key biomarkers for early and accurate diagnosis. However, conventional diagnostic methods such as Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) are invasive, costly, and unsuitable for routine screening. Field-effect transistor (FET)-based biosensors are promising alternatives because of their high sensitivity, specificity, portability, and low cost. In this study, we propose a Triangular Gate Fin Field Effect Transistor (TG FinFET) designed as a Dielectric Modulated (DM) biosensor for AD biomarker detection. Biomolecule interaction at the gate interface alters the effective dielectric constant, leading to significant variations in electrical parameters such as surface potential, electric field, threshold voltage, drain current, and transconductance. Analytical modeling and simulations demonstrate that the TG FinFET exhibits superior sensitivity compared to conventional FET-based biosensors. These results highlight the potential of TG FinFETs as a scalable and CMOS-compatible platform for early Alzheimer’s diagnostics and point-of-care healthcare applications. The proposed TG FinFET biosensor exhibits a wide linear range of 10⁻⁶–10³ pg/mL with a low Limit of Detection (LOD) of 1 × 10⁻⁴ pg/mL for Alzheimer’s biomarker detection.