Design, realization and characterization of all-arround SiO2/Al2O3 gate, suspended silicon nanowire chemical field effect transistors

We present a sensor platform associated to silicon-nanowire chemical field effect transistors (Si-nw-ChemFET). Innovations concern the use of networks of suspended silicon N ⁺ /P/N ⁺ nanowires as conducting channel, the realization by thermal oxidation and Atomic-Layer Deposition (ALD) of a SiO ₂ /Al ₂ O ₃ gate insulator all-around the silicon nanowires, and their final integration into covered SU8-based microfluidic channels. The Si-nw-MOSFET/ChemFET fabrication process and electrical/electrochemical characterizations are presented. The fabrication process did not need an expensive and time-consuming e-beam lithography, but only fast and “low cost” standard photolithography protocols. Such microdevice will provide new opportunities for biochemical analysis at the micro/nanoscale.