Improved Piezoelectric MEMS Acoustic Emission Sensors

This paper describes two innovative methods for improving the sensitivity of piezoelectric MEMS acoustic emission (AE) sensors. By optimizing the top electrode dimensions and adding a dummy structure to it, the peak sensitivity of the fabricated MEMS AE sensors at resonance can be improved to 148 V/m/s, which is about 10-fold greater than that of sensors with a full-size top electrode. Standard pencil-lead break (PLB) tests are conducted to verify the detection capability of AE waves. As a result, the fabricated single-type piezoelectric MEMS AE sensor, which has a peak sensitivity of 45 V/m/s, is shown to have the same level of detection sensitivity as a commercial bulk piezoelectric AE sensor.