Ultra-Low Noise Schottky Junction Tri-Gate Silicon Nanowire FET on Bonded Silicon-on-Insulator Substrate

Abstract

Random trapping and detrapping of charged carriers in the vicinity of gate oxide/Si interface has for long been considered as the dominant noise source in Si nanowire (SiNW) FET-based biochemical sensors. Here we extend our previous work presenting a Schottky junction tri-gate SiNWFETs (SJGFET) fabricated on a bonded silicon-on-insulator (SOI) substrate, aiming for ultra-low device noise generation. The SJGFET exhibits near-ideal gate coupling efficiency with a subthreshold swing of 66 mV/dec. Its gate-referred voltage noise, S{\text {vg}} , are {1.2}\times {10}{-{10}} and {1.1}\times {10}{-{11}}\,\,\text {V}\,\,\mu \text{m} /Hz at 1 and 10 Hz, respectively. These S{\text {vg}} values are significantly lower than that of previously reported FET-based sensors. More importantly, S{\text {vg}} of the SJGFET are below the reported voltage noise generated by the oxide/electrolyte sensing interface. Using our SJGFET as the signal transducer can greatly relieve the concern of the adverse effect from the intrinsic device noise in biochemical sensing applications.