Modeling and detecting response of micromachining square and circular membranes transducers based on AlN thin film piezoelectric layer

Vibration analysis of square and circular piezoelectric micro ultrasonic transducers (pMUTs) in the 100 kHz range as a function of experimental tools are reported. Analytical and 3D finite element method analysis using Comsol software has been performed to model static, modal and vibration behavior of these membranes. Comparison with standard impedancemeter measurement is shown to assess the performance of Laser Doppler Vibrometry system. Mechanical and electrical characterization and comparison with a model results are presented and discussed. The measured resonances frequencies of membrane can be weak and superimposed on important parasitic signal, which may mask the desired mechanical resonance signal. Our results revealed the real roles of the simulations and the combination of the experimental tools to get measurement accuracy. Subsequently, this piezoelectric micro-transducer was successfully tested as a sounder in air. These investigations offer guidance for the pMUTs design and associated electronic circuit but might at the same time be instructive and beneficial to further sensor applications.