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M. Fischeneder, M. Oposich, M. Schneider, U. Schmid:
"Tuneable Q-Factor of MEMS Cantilevers with Integrated Piezoelectric Thin Films";
Sensors, 18 (2018), 3842 - 3853.

In atomic force microscopes (AFM) a resonantly excited, micro-machined cantilever with a
tip is used for sensing surface-related properties. When targeting the integration of AFMs into vacuum
environments (e.g., for enhancing the performance of scanning electron microscopes), a tuneable
Q-factor of the resonating AFM cantilever is a key feature to enable high speed measurements
with high local resolution. To achieve this goal, in this study an additional mechanical stimulus
is applied to the cantilever with respect to the stimulus provided by the macroscopic piezoelectric
actuator. This additional stimulus is generated by an aluminum nitride piezoelectric thin film actuator
integrated on the cantilever, which is driven by a phase shifted excitation. The Q-factor is determined
electrically by the piezoelectric layer in a Wheatstone bridge configuration and optically verified in
parallel with a laser Doppler vibrometer. Depending on the measurement technique, the Q-factor is
reduced by a factor of about 1.9 (electrically) and 1.6 (optically), thus enabling the damping of MEMS
structures with a straight-forward and cheap electronic approach.

http://dx.doi.org/10.3390/s18113842