Characterization and simulation of high-quality AlN-actuated resonant suspended beams

Micro-cantilevers and micro-bridges actuated by sputter-deposited aluminium nitride (AlN) thin films were measured with a scanning laser Doppler vibrometer up to 6 MHz, covering more than 10 resonance modes of different nature. A finite element model (FEM) was used to simulate the modal response of the micromachined structures. The comparison between experiment and simulation, regarding modal shapes and frequencies, resulted in an excellent agreement, what confirmed the quality of the structures. Finally, we point out, and illustrate with the help of micro-bridges, the importance for a locally tailored distribution of electrical excitation on the top surface of the device, in order to either optimize or cancel out the displacement of a given mode.

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