Multifunctional Ion‐Sensitive Floating Gate Fin Field‐Effect Transistor with Three‐Dimensional Nanoseaweed Structure by Glancing Angle Deposition Technology

Abstract A multifunctional ion‐sensitive floating gate Fin field‐effect transistor (ISFGFinFET) for hydrogen and sodium detection is demonstrated. The ISFGFinFET comprises a FGFET and a sensing film, both of which are used to detect and improve sensitivity. The sensitivity of the ISFGFinFET can be adjusted by modulating the coupling effect of the FG. A nanoseaweed structure is fabricated via glancing angle deposition (GLAD) technology to obtain a large sensing area to enhance the sensitivity for hydrogen ion detection. A sensitivity of 266 mV per pH can be obtained using a surface area of 3.28 mm². In terms of sodium ion detection, a calix[4]arene sensing film to monitor sodium ions, obtaining a Na⁺sensitivity of 432.7 mV per pNa, is used. In addition, the ISFGFinFET demonstrates the functionality of multiple ions detection simultaneously. The sensor arrays composed of 3×3 pixels are demonstrated, each of which comprise of an FGFET sensor and a transistor. Furthermore, 16×16 arrays with a decoder and other peripheral circuits are constructed and simulated. The performance of the proposed ISFGFinFET is competitive with that of other state‐of‐the‐art ion sensors.