A non-ideal hybridization issue for vertical TFET-based dielectric-modulated biosensor

Abstract

This article evaluates SiGe/Si heterojunction vertical tunnel field-effect transistor (VTFET-hetero) biosensors, using SiGe in the source region to enhance sensitivity. It detects smaller analyte concentrations for biomedical applications. Non-ideal sensor behavior is explained by steric hindrance and irregular probe/receptor positions. Based on the simulation results, sensitivity is determined for four different cases in which partially filled nanogaps have decreasing, increasing, concave, and convex profiles. Simulation shows concave step profiles having the highest sensitivity. The VTFET-hetero structure exhibits higher sensitivity than horizontal biosensors, achieving a sensitivity of 8.64 × 10⁷ for immobilized charged biomolecules.