Tunable piezoresistive NEMS pressure sensor simulation under various environmental conditions

In this letter, the nanoelectromechanical system (NEMS)-based piezoresistive pressure sensor is proposed on a circular diaphragm using a twin junctionless nanowire (JL-NW) gate-all-around (GAA) field-effect transistor (FET) for highly piezoresistive sensitivity. The maximum sensitivity is observed in the subthreshold regime due to the tunability of channel formation diameter in the depletion region (subthreshold region) by a low gate biasing, which is ∼4 times higher than the on-state conditions (partially depletion region). However, the piezoresistive sensitivity is reduced by ∼4.5% and ∼14.7% in the on-states (at the threshold voltage and above it) and subthreshold regime (below the threshold voltage), respectively, due to a slight mobility reduction by the intrinsic and phonon scattering when the environmental temperature increased from 20 °C to 80 °C. In the subthreshold region, the sensitivity is a little more reduced with increasing environmental temperature from 20 °C to 80 °C because the surface scattering is higher due to the high electric field perpendicular to the channel formation. But still, the impact of environmental temperature does not sensitively dominate the performance of sensing elements. Thus, the better resolution of piezoresistivity and less environmental temperature impact on sensitivity permits the JL-NW GAA FET as an emerging piezoresistive sensor in NEMS.