Performance Optimization of Piezoelectric MEMS Speaker with Cantilever Diaphragm Array

This paper presents the concept to optimize the performance of a piezoelectric MEMS speaker with a cantilever diaphragm array by delicate structure design. The optimization focuses on the dimensions design of each cantilever unit of the array to balance the sound pressure level and frequency range under the condition of a limited area. The optimized design was first proposed based on the simulation and followingly a proof of experiment is conducted by fabricating a piezoelectric cantilever diaphragm array on a SOI wafer. As a result, measurements in the free field illustrate that the maximum SPL of the proposed microspeaker reaches 99 dB in the range of 200 Hz – 20 kHz with 3.0 Vp-p driving voltage.