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M. Dorfmeister, M. Schneider, U. Schmid:
"A Bistable Ultrasonic Mems Device With An Integrated Piezoelectric Scandium-Aln Thin Film Actuator For Switching";
Talk: 20th International Conference on Solid State Sensors, Actuators and Microsystems & Eurosensors XXXIII (Transducers & Eurosensors XXXIII), Berlin, D; 06-23-2019 - 06-27-2019; in: "20th International Conference on Solid State Sensors and Actuators (Transducers 19)", IEEE, CFP19SSA-ART (2019), ISBN: 978-1-5386-8104-6; 853 - 856.

This work reports on a novel concept for switching
between the two stable states of compressively pre-stressed
bistable MEMS membranes using integrated piezoelectric
scandium aluminum nitride (ScxAlN1-x) thin film actuators.
The minimum voltage needed to switch between the stable
states was about 23% lower than using a pure AlN layer.
Depending on the membrane diameter being in the range
between 600 to 800 μm, the total displacement after
switching is about 10 to 16 μm. The array consists of 15
membranes on a 6x6 mm2 die, whereas the total membrane
thickness was 3.12 μm. The FFT of a bistable switching
process showed most beneficial peaks for ultrasound
generation in the range of 70 - 90 kHz with extremely high
acceleration values in the range of 105 m·s-2, thus promising
high sound pressure levels.