A Novel NH3 Sensing Mechanism Based on Au Pads Activated Schottky Barrier MOSFET on Silicon-on-Insulator With Extremely High Sensitivity at Room Temperature

With electric stressing pretreatment applied by the stress on back gate, this work demonstrates a novel gas sensing mechanism based on Au source/drain pads activated Schottky barrier-FET (SB-FET) fabricated on silicon-on-insulator (SOI) with extremely high sensitivity at room temperature, which is very different from the conventional working mechanism using gas molecular-induced channel resistance modulation for MOSFET type gas sensor. As a proof-of-concept, the interactions between ammonia (NH3) gas as the analyte and Au pads realize the SB modulation, which effectively improves the sensitivity. Besides, the SOI substrate makes the enhanced NH3 adsorption/desorption possible using the buried oxide (BOX) induced electric stress. As a result, the proposed SB-FET gas sensor shows an extremely high leakage current sensitivity up to 4 189000% for 900-ppb NH3 with a low detectable concentration down to 120 ppb.