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M. Kucera, T. Manzaneque, J.L. Sànchez-Rojas, A. Bittner, U. Schmid:
"Lock-in Driven Quality Factor Enhancement with Parasitic Effect Compensation of a Self- Actuated Piezoelectric MEMS Cantilever";
Vortrag: IEEE Ultrasonics Symposium, Dresden; 07.10.2012 - 10.10.2012; in: "Proceedings IEEE Ultrasonics Symposium", IEEE, (2012), ISBN: 978-3-99033-045-6.

State of the art quality factor amplification for
resonant MEMS cantilevers requires either complex electronics
like highly sensitive analogue circuits or optical read-out to
extract a resonance peak shaped feedback signal. In this
investigation, a lock-in amplifier is used to extract the Q-control
feedback signal which is proportional to the piezoelectric current.
Due to influences related e.g. to the layered device architecture
and fabrication intolerances of piezoelectric driven MEMS
resonators the resonance peak shaped conductance can have an
additional offset and a slope in the baseline as well as a dominant
susceptance. All these parasitic effects are getting more dominant
with higher frequencies by increasing the complex feedback
signal. Hence, a higher lock-in input range has to be used leading
in an inferior resolution when determining the real part. In this
study, an approach for the compensation of these parasitic effects
is presented, which gives the possibility to decrease the offset as
well as the dominant suceptance leading to increased
measurement sensitivity. Using this Q-factor enhancement
technique this important device parameter was increased from
1766 to about 9679 in air.

State of the art quality factor amplification for
resonant MEMS cantilevers requires either complex electronics
like highly sensitive analogue circuits or optical read-out to
extract a resonance peak shaped feedback signal. In this
investigation, a lock-in amplifier is used to extract the Q-control
feedback signal which is proportional to the piezoelectric current.
Due to influences related e.g. to the layered device architecture
and fabrication intolerances of piezoelectric driven MEMS
resonators the resonance peak shaped conductance can have an
additional offset and a slope in the baseline as well as a dominant
susceptance. All these parasitic effects are getting more dominant
with higher frequencies by increasing the complex feedback
signal. Hence, a higher lock-in input range has to be used leading
in an inferior resolution when determining the real part. In this
study, an approach for the compensation of these parasitic effects
is presented, which gives the possibility to decrease the offset as
well as the dominant suceptance leading to increased
measurement sensitivity. Using this Q-factor enhancement
technique this important device parameter was increased from
1766 to about 9679 in air.