Tunable Piezoelectric MEMS Microphone Based on Inverse Piezoelectric Effect

A tunable MEMS microphone is crucial for achieving superior performance in challenging acoustic scenarios. This work demonstrates a novel piezoelectric MEMS microphone with tunable sensitivity. The tuning mechanism lies in the inverse piezoelectric effect. It can be achieved either through the static stiffness perturbation with DC voltage, or the parametric pumping with AC voltage. The proposed device achieves a baseline sensitivity of -39dB without tuning. With a DC tuning voltage (1V) applied over the membrane, the sensor output amplitude has been improved by 37.84% under 1kHz acoustic pressure input. With an AC tuning voltage (1Vpk 2kHz), the output amplitude has been improved by 33.42%. Under 1kHz electrical excitation, the tuning ratios are 11.20% for DC and 4.54% for AC, respectively. These enhancements demonstrate the microphone proposed a strong potential for next-gen audio applications, including adaptive voice systems, and AI speech recognition.