Sensitivity manipulation on micro-machined resonant electrometer toward high resolution and large dynamic range

A micro-resonant electrometer with the scheme of sensitivity manipulation is proposed to realize the high resolution and large dynamic range based on a mechanical resonator and actuator. As the key sensing element, the double-ended tuning fork resonator has a quality factor close to 10 000 and low motional resistance below 0.5 M Omega. Electrical and mechanical nonlinear features of the resonator are investigated. The charge sensing functionality based on the axial strain modulation scheme is calibrated with a high resolution of 2.6 fC under 0.46 ppm frequency fluctuation. With the manipulation, the sensitivity is linearized from quadratic and further decreased to extend the dynamic range by 358.47% up to 12.38 pC. Meanwhile, the frequency fluctuation is also stabilized under 70 mHz to enhance the short-term stability of the sensor. Published by AIP Publishing.