High Sensitivity Piezoelectric MEMS Microphones Based on AlN with Cavity-SOI

With the rapid development of microelectromechanical systems (MEMS), microphones need to be more miniaturized and integrated. This paper presents an AIN-based high sensitivity piezoelectric MEMS microphone (PMM) fabricated on a cavity silicon-on-insulator (CSOI) platform. The microphone consists of six trapezoidal piezoelectric cantilevers, where the fixed end of the beam is located in the center of the hexagonal working area. Through theoretical analysis and finite element method (FEM) simulation, we have demonstrated that the proposed structure has higher electro-acoustic conversion sensitivity than the reference device. The receiving sound pressure sensitivity of the designed device is −80.5 dB (re 1V/Pa). In addition, its near-field radiated sound pressure is 75.6 dB SPL under the excitation of 1Vrms.