Gate-all-around nanowire FET sensors with ultrahigh sensitivity and low noise

Abstract

In this research work, new kinds of field-effect transistor (FET)-based sensing elements were developed to maximize the detection limits of conventional piezoresistors. These sensing elements were able to enhance the piezoresistive sensitivity and reduce the intrinsic noise, which significantly improved the detection limits and make them adaptable for lower strain detection applications.

To further improve the piezoresistive sensitivity, the gate-all-around (GAA) nanowire field-effect transistor (NWFET) was presented as a novel, miniaturized and lower voltage driven piezoresistive sensing element. The piezoresistive coefficient of the NWFET enhanced up to seven times and reduction of the electronic noise improved the sensor resolution by sixteen times compared to the planar FET-based sensing element. Results showed that NWFET-based sensing elements operated at low bias with higher piezoresistance and can be used to measure lower strain values with high signal-to-noise ratio.

The development of the GAA channel structure was further implemented to design and fabricate a novel junctionless nanowire field-effect transistor (JL-NWFET). The JL-NWFET operated by bulk conduction and showed significantly lower electronic noise than the NWFET counterpart. The picoampere drain current noise helped to achieve a four times better resolution for the JL-NWFET than that of the inversion mode NWFET. The preliminary results achieved in this research work indicate that the GAA JL-NWFET-based sensing element has miniaturized size, higher piezoresistive sensitivity and lower intrinsic noise and can be potentially used in ultrasensitive strain sensors.