Ultra-sensitive label-free bio-detection via dielectric-modulated GOSC-SOI-TFET

In this work, a highly sensitive label-free dielectric-modulated biosensor based on a Gate-Over-Source-Channel Silicon-on-Insulator Tunnel Field-Effect Transistor (GOSC-SOI-TFET) is proposed and systematically investigated. The novelty of the design lies in the asymmetric gate configuration with a strategically positioned nanocavity near the gate–source interface, providing enhanced electrostatic control and improved band-to-band tunneling efficiency. A comprehensive TCAD-based simulation framework, comprising non-local BTBT and trap-assisted tunneling models, is applied to assess the device reaction toward neutral and charged biomolecules. To achieve realistic operation, non-ideal factors like steric hindrance and non-uniform probe dispersion are also considered. The results demonstrate that the sensor sensitivity is substantially impacted by biomolecule location, with best performance achieved when analytes are situated near the source-channel tunneling junction. The proposed biosensor demonstrates an ON-current sensitivity of 6.09 × 10⁸ for gelatin biomolecules, which is approximately 1.7× higher than that of conventional TFET-based biosensors, while operating at a reduced drain voltage of Vds = 0.7~V (about 30% lower). This highlights its potential for low-power and high-performance biomedical sensing applications.