Performance optimization of epitaxial-layer based Si/SiGe hetero-junction area scaled tunnel FET label-free biosensors considering steric hindrance

Abstract

This paper explores Si/SiGe hetero-junction dielectrically modulated area-scaled tunnel FET (DM-ASTFET) for label-free bio-sensing applications. The proposed sensor can detect bioanalytics such as protein, APTES, Choline Oxidase and Uricase. We have also investigated the influence of quantum confinement on the proposed device, and the onset voltage shifted by 0.1–0.3 V, as reported, without affecting the sensitivity mechanism. Sensitivity improvement is observed when the gate oxide length is 20 nm and the cavity length is 50 nm for a given bio-molecule due to the increased cross-section area for tunneling. The impact of epitaxial engineering on the biosensor's performance is also investigated in this work. A physics-based in-depth explanation of steric hindrance on the performance of the proposed sensor is also presented in this work. Finally, the optimum device design improves the sensitivity of ION ∼×103 and Vth ∼×2 times.