Kumar P., Kumar N., Dixit A., Ansari M.H.R., Bagga N., Gandhi N., Kondekar P.N., García C.P., Georgiev V.
Solid State Electronics, vol. 229, art. no. 109159, 2025
This work discusses the sensitivity response of a feedback field effect transistor-based ion sensor (ISFBFET). To precisely predict the sensing behavior, the Gouy-Chapman-Stern and site-binding methods are used as the principle models in a detailed TCAD study. For charge binding, the deposition of Si<sub>3</sub>N<sub>4</sub> over SiO<sub>2</sub> is used as a sensing element. The behavior of the ISFBFET is discussed against gate work function (Φ<sub>G</sub>) engineering and bulk pH. The performance of the sensor is analyzed using I<sub>DS</sub>-V<sub>DS</sub>, I<sub>DS</sub>-transit time, and snap-back characteristics. Sensitivity is evaluated in terms of constant current and constant voltage using snap-back characteristics and at Φ<sub>G</sub> = 4.4 eV, the highest sensitivity of 2.35 and 405 is obtained. The proposed work can help in designing FBFET based ion-sensors for sensing biomolecules or amino acids.
