Characterization of piezoresistive-Si-nanowire-based pressure sensors by dynamic cycling test with extralarge compressive strain

A novel pressure sensor using piezoresistive silicon nanowires (SiNWs) embedded in a suspended multilayered diaphragm is investigated by a probe-based dynamic cycling test combining the standard bulge testing setup. By utilizing the high fracture stress of the SiN _x film, we explored the behavior of the SiNW under a level of extralarge compressive strain for the first time, including strain levels of more than 2.1% under the static testing and 1.5% under the dynamic testing. Drift of the initial resistances of the SiNW was observed at different time intervals during the dynamic testing under a compressive strain of higher than 1.3%, while the sensitivity of the pressure sensor basically keeps unchanged. However, there was almost no drift or degradation observed in the sensor characteristics when an equivalent point loading within the application working range is applied to the pressure sensor during the dynamic testing.