Interface dissipation in piezoelectric MEMS resonators: an experimental and numerical investigation

Piezoelectrically actuated MEMS resonators can be very effective for timing applications even though experiments show that mode coupling and dissipative phenomena can affect their performance. Experiments demonstrate the occurrence of a much larger mechanical dissipation with respect to similar devices actuated capacitively. This contribution addresses the analysis of different dissipation phenomena. Refined numerical tools have shown that anchor and thermoelastic losses alone cannot reproduce experimental data. Hence a model to account for surface dissipation has been considered introducing a viscous term at the interfaces. A set of specific length extensional devices with different dimensions, vibrating modes and piezo- patterns have been produced and tested to validate the model. The numerical predictions show a good agreement with the experimental tests for different device lengths and actuation frequencies, confirming the initial assumption.