Design and Optimization of Piezoelectric Diaphragm for Self-Powered Acoustic Sensor

Abstract

A self-powered piezoelectric material-based sensor has miniaturization and mass production capabilities. The finite element analysis shows results prior to device fabrication, which discover potential defects in the design, improve sensor performance, and lead to cost-effective fabrication. This study reveals the trade-offs between sensitivity and frequency range of the proposed device and provides an optimized diaphragm design in terms of material choice and dimension. Regardless of the cavity and holes in the silicon substrate, the optimized design is applicable for any piezoelectric square shaped diaphragm-based acoustic sensor. The constraints of the MEMS fabrication technique are considered while selecting a parameter range for the diaphragm. The obtained results from COMSOL Multiphysics with diaphragm area 12.25 mm2, ZnO (2.5 µm), and silicon layer (5 µm) shows a resonance frequency of 39 kHz and sensitivity of 1.17 mV at 1 kHz of frequency, results in higher sensitivity with maximum feasible frequency range for optimized design.