Membraneless Piezoelectric MEMS speakers based on AlN Thin Film

Abstract

This paper reports piezoelectric aluminum nitride (AlN) based microelectromechanical systems (MEMS) speakers. We introduce a novel geometry of microspeakers based on AlN to meet the requirements of modern applications such as phones, tablets, laptops, and in ear applications. We introduce the principle, design, and characterization results. The speakers were fabricated on cavity silicon on insulator (SOI) substrate and characterized by using an electroacoustic tester. This paper considers the acoustic performance of the speakers. The results show that the speakers gave us a high sound pressure level (SPL) of more than 78 dB for circle geometry when applying 2 volts on the electrodes. These results are equal for PZT MEMS speakers moreover AlN opens the door to integrate the speakers and the ASIC on the same chip. The size of the different geometries’ speakers isn’t exceeded 3mm × 3mm. These geometries offer a breakthrough in acoustic performance, a frequency response, and low power consumption.