Fabrication and application of silicon nanowire transistor arrays for biomolecular detection

We present a novel approach for large-scale silicon nanowire (SiNW) array fabrication for bioelectronic applications. Nanoimprint lithography was combined with standard CMOS processing on 4 in. SOI wafers in order to produce highly integrated arrays of silicon nanowire field-effect transistors (SiNW-FET). With a very smooth surface due to wet anisotropic etching, SiNW-FET arrays show a good electronic performance with a subthreshold slope of about 85 mV/decade. When applying a front-gate control of the wires via an electrochemical reference electrode, reliable electronic performance inside an electrolyte solution can be achieved. Our SiNW-FET sensors exhibit almost no electronic hysteresis on forward and backward bias sweeps. In this article the fabrication process, electronic and electrochemical characterizations and first biomolecular detection experiments are presented. For biodetection experiments we used a differential readout between molecule-free wires and wires carrying covalently attached biomolecules such as short, single-stranded DNA or biotin. With our SiNW-FET arrays a reliable detection of biomolecular layers can be achieved.