Ultrasensitive Pressure Sensor Based on an Integrated Circular Piezoelectric MEMS Resonator and Diaphragm Structure

In this letter, we report an ultrasensitive pressure sensor based on an integrated circular piezoelectric microelectromechanical resonator and stainless-steel diaphragm structure. Finite-element analysis is conducted to validate the working principle of the sensor, identify modes with high-pressure sensitivity, and estimate the resonance frequency drift. The sensor operates on the principle of frequency shift caused by the coupling between the applied pressure and stress of the resonator. The high electromechanical coupling coefficient of lead zirconate titanate facilitates seamless transduction between the physical domains of interest. The sensitivity of the sensor is 31 711 and 14 600 ppm/bar for the first and second flexural modes with nonlinearity of 2.2% full scale (FS) and 0.84% FS, respectively, in the operating range of 0-5 bar at room temperature. The sensor exhibits excellent repeatability for multiple bidirectional pressure sweep. The proof of concept demonstrated in this letter will enable miniaturization and batch fabrication of pressure sensors with high sensitivity and bandwidth of operation.