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Publications in Scientific Journals:

M. Dorfmeister, M. Schneider, U. Schmid:
"3D characterisation of piezoelectric bistable MEMS membranes during switching";
Sensors and Actuators A: Physical, 298 (2019), 1 - 9.



English abstract:
This paper reports on a novel measurement concept for the 3D characterisation of bistable MEMS membranes with an integrated piezoelectric thin film actuator to stimulate the switching between the two ground states. Membranes show bistable behaviour when a characteristic stress value, the so called critical stress, is exceeded. Sputter-deposited aluminium nitride (AlN) is used on the one hand as stress inducing layer and on the other hand to initiate the switching process. For this purpose, a sequence of five rectangular voltage pulses with varying peak-to-peak voltage levels in the range of 30-40 Vpp was applied. The method to measure the 3D movement of the membrane during the switching process is based on a combination of static Whitelight interferometry (WLI) and dynamic laser Doppler Vibrometer (LDV) measurements. Thus, an 11 by 11 measurement grid covers the membrane surface requesting in turn 121 switching processes to reconstruct the complete membrane trajectory. In this work two different electrode configurations were used, namely a fully covered and a four-segmented cake sliced design. We showed that the switching modes of the membranes are similar to the membrane specific eigenmodes, whereas the 01-mode is preferred by the first and the 11-mode by the four segmented electrode design. When exciting only two of the four electrode segments the switching between the ground states requests a 2.5-5% lower Vpp but needs seven instead of five pulses. Assuming that the membrane shape during the bistable switching process is decisive for some applications as in e.g. acoustics for sound generation, this method is most valuable for the characterization of the basic device performance when exploiting buckled membranes as key component.


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1016/j.sna.2019.111576


Created from the Publication Database of the Vienna University of Technology.