Design, modeling and simulation of square diaphragm based, piezoelectric (Aln) mems acoustic sensor for high spl measurements

Abstract

This paper reports the aluminum nitride (AlN) based piezoelectric MEMS acoustic sensor for aeroacoustic applications. The acoustic sensor reported, is square diaphragm based, which is easy to fabricate. Thin film AlN is considered as the sensing layer to exploit the property of CMOS process compatibility. The structure dimensions are chosen to have the cut-on, cut-off and resonance frequency of 20 Hz, 10 kHz and 45 kHz respectively. The sensitivity of the sensor is 103 and 84 µv/Pa in case of central and outer annular electrode pattern respectively. Further more a generic lumped model of square diaphragm based acoustic sensor is also reported. The results thus obtained from lumped model simulation using MULTISIM 13.0 and distributed model simulation using Comsol-Multiphysics are in good agreement with the experimentally obtained results, which validates the lumped model of the square diaphragm based acoustic sensor.