The F− Sensitivity Enhancement of SiNW ISFET with Poly-LaF3 Sensing Membrane

Abstract

Abstract Silicon nanowire ion sensitive field effect transistors (SiNW ISFETs) with polycrystalline lanthanum fluoride (poly-LaF3) is presented to enhance its sensing characteristics for detection of fluoride ion (F−). The poly-LaF3 sensing membrane is deposited by using a thermal evaporation process with the substrate temperature of 600 °C on the SiNW channel. The electrical characteristics and current sensitivity for F− are investigated as SiNW width is varied between 100 nm, 500 nm, and 2000 nm. The 100 nm SiNW width ISFETs exhibits the lowest subthreshold swing of 141 mV/dec and the highest current sensitivity of 182.15%. This improved sensing characteristic of SiNW ISFETs comes from the enlarged gate controllability as diminishing the SiNW width.