Electrolyte gated based pH sensing vertical TFET biosensor: Design, simulation and noise analysis

In this manuscript, a pH-based stepped oxide gate underlap vertical tunnel field-effect transistor (hetero-pHVTFET) biosensor with GaSb-doped layers is explored. A novel feature of the proposed device involves the use of stepped oxides with underlapped cavity gates. During the fabrication of devices, several challenges have emerged. A vertical tunnel field-effect transistor (VTFET) is proposed in this study for the detection of biological molecules such as proteins, enzymes, deoxyribonucleic acids, and others using label-based electrical recognition through the Stern layer. The simulation model provides a generalized solution for biological molecule detection, featuring the effects of pH sensing. Surface potential and device current (IDS) are investigated in relation to pH changes. Moreover, pH sensors have also been used to measure changes in hydrogen ion concentration within electrolyte solutions and to examine the sensitivity of proposed biological sensors based on alterations in the density of states. A 40 nm cavity length of the proposed hetero-pHVTFET biosensor is estimated to have a drain current sensitivity of 9.2 × 10⁵.