Design and characterization of a piconewton MEMS force sensor

In this paper, a high-precision resonant MEMS force sensor is reported. A micromanipulation system with vision inspection system is established for calibration and materials’ mechanical properties testing. Due to the ultra-high resolution of the designed force sensor, a precise calibration technique is developed by using the electrostatic force compensated by the calibration displacement as a reference. Through the calibration process, the relative error is reduced to 0.1 % at sub nanonewton level, which was thoroughly studied both analytically and experimentally. The calibration results highlight that the proposed force sensor exhibits an impressive resolution of 20.13 pN and a low noise level of 4.9 pN/Hz^1/2@1Hz. The measurement dynamic range of the sensor reaches 120 dB. By measuring the stiffness of AFM probe, the potential application of the proposed sensor in evaluating the mechanical properties of micro and nano materials is demonstrated, which will contribute to the exploration of nanoscale material science.