Simulation Study of Flexible Mems Piezoelectric Hydrophones Based on Sc0.3Al0.7N

Flexible MEMS piezoelectric hydrophone with high-performance can be used in bent surface devices and the Internet of things which has a good development prospect. In this paper, a flexible piezoelectric hydrophone based on Sc0.3Al0.7N piezoelectric thin films is designed and the static/transient reception performance is systematically studied by using the three-dimensional finite element methods (3D-FEM) in COMSOL simulation software. Compared with traditional rigid piezoelectric hydrophones, the flexible MEMS piezoelectric hydrophone based on Sc0.3Al0.7N film proposed here exhibits high reception performance in aquatic fluid environments with receiving sensitivity level up to-140dB. In addition, the mechanical bending performance of the flexible MEMS piezoelectric hydrophones was further investigated. Simulation results indicate that the resonant frequency of the piezoelectric hydrophone decreases from 39kHz to 38kHz after filling the substrate with flexible polyimide (PI), which enhancing its ability to detect lower-frequency underwater acoustic signals. Furthermore, the reception sensitivity level of the flexible MEMS piezoelectric hydrophone based on Sc0.3Al0.7N film was improved by 5 dB compared to that of a rigid hydrophone. Additionally, the reception performance of the flexible MEMS piezoelectric hydrophone remains stable even working in bending state with the bending radius of 1.07mm. These results provide constructive suggestions for improving the reception performance of flexible hydrophones.