Design and Simulation of AlN-based MEMS Acoustic Sensor for High SPL Measurement

The paper presents the design and simulation of both AlN-based and ZnO-based MEMS acoustic sensor for high SPL (120–180 dB) over a wide frequency range (30 Hz to 8 KHz) using COMSOL multiphysics. The sensor structure consists of a 25 μm-thick Silicon diaphragm loaded with a piezoelectric layer (of 3 μm thickness) sandwiched between two Al electrodes. The comparison of both piezoelectric materials based sensor was performed. The simulated result shows the wide bandwidth and high resonant frequency for AlN-based acoustic sensor (43 KHz) in comparison to ZnO-based MEMS acoustic sensor (39 KHz). The sensitivity of the designed AlN-based acoustic sensor was found to be 293μV/Pa.