Articles | Volume 14, issue 2
https://doi.org/10.5194/jsss-14-227-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/jsss-14-227-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Local pressure field distribution of bistable PMUTs for distance sensing
Michael Schneider
CORRESPONDING AUTHOR
Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna, Austria
Christian Doppler Laboratory for PiezoMEMS, TU Wien, 1040 Vienna, Austria
Mahdi Mortada
Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna, Austria
Christian Doppler Laboratory for PiezoMEMS, TU Wien, 1040 Vienna, Austria
Dominik Mayrhofer
Institute of Fundamentals and Theory in Electrical Engineering, TU Graz, 8010 Graz, Austria
Manfred Kaltenbacher
Institute of Fundamentals and Theory in Electrical Engineering, TU Graz, 8010 Graz, Austria
Ulrich Schmid
Institute of Sensor and Actuator Systems, TU Wien, 1040 Vienna, Austria
Related authors
Martin Fischeneder, Michael Schneider, and Ulrich Schmid
J. Sens. Sens. Syst., 15, 53–65, https://doi.org/10.5194/jsss-15-53-2026, https://doi.org/10.5194/jsss-15-53-2026, 2026
Short summary
Short summary
Scanning electron microscopy (SEM) and atomic force microscopy (AFM) enable sub-nanometer surface imaging and complement each other's limitations. Integrating AFM into a SEM vacuum chamber combines their strengths. However, vacuum increases the cantilever's Q factor and reduces scan speed. We develop a feedback circuit and a piezoelectric MEMS cantilever to tune the Q factor, enabling vacuum AFM at air-like speeds.
Dominik Huber, Michael Schneider, Paul Fulmek, Georg Pfusterschmied, and Ulrich Schmid
J. Sens. Sens. Syst., 14, 89–98, https://doi.org/10.5194/jsss-14-89-2025, https://doi.org/10.5194/jsss-14-89-2025, 2025
Short summary
Short summary
Photo-thermal actuation and laser Doppler vibrometry enable fast, contactless characterization of MEMS (microelectromechanical system) resonators already before electrical connections are made. This paper details a tailored setup combining a precision stage, vacuum chamber, laser diode, and vibrometer to analyze silicon MEMS devices on a wafer level. Tests reveal how silicon device layer thickness affects resonance frequency and identify dominant loss mechanisms in different vibrational modes.
Martin Fischeneder, Michael Schneider, and Ulrich Schmid
J. Sens. Sens. Syst., 15, 53–65, https://doi.org/10.5194/jsss-15-53-2026, https://doi.org/10.5194/jsss-15-53-2026, 2026
Short summary
Short summary
Scanning electron microscopy (SEM) and atomic force microscopy (AFM) enable sub-nanometer surface imaging and complement each other's limitations. Integrating AFM into a SEM vacuum chamber combines their strengths. However, vacuum increases the cantilever's Q factor and reduces scan speed. We develop a feedback circuit and a piezoelectric MEMS cantilever to tune the Q factor, enabling vacuum AFM at air-like speeds.
Dominik Huber, Christoph Schallert, Andre Gesing, Doris Steinmüller-Nethl, Georg Pfusterschmied, and Ulrich Schmid
J. Sens. Sens. Syst., 15, 9–21, https://doi.org/10.5194/jsss-15-9-2026, https://doi.org/10.5194/jsss-15-9-2026, 2026
Short summary
Short summary
We present an automated, contactless method to map thin film thickness and stress across microelectromechanical systems (MEMS) wafers. Using white light interferometry on cantilevers and step profiles, we extract both mean and gradient stress with orientation sensitivity. Applied to six thin films, the approach reveals process-dependent variations, offering a reliable tool for evaluating and comparing MEMS materials and fabrication methods.
Dominik Huber, Michael Schneider, Paul Fulmek, Georg Pfusterschmied, and Ulrich Schmid
J. Sens. Sens. Syst., 14, 89–98, https://doi.org/10.5194/jsss-14-89-2025, https://doi.org/10.5194/jsss-14-89-2025, 2025
Short summary
Short summary
Photo-thermal actuation and laser Doppler vibrometry enable fast, contactless characterization of MEMS (microelectromechanical system) resonators already before electrical connections are made. This paper details a tailored setup combining a precision stage, vacuum chamber, laser diode, and vibrometer to analyze silicon MEMS devices on a wafer level. Tests reveal how silicon device layer thickness affects resonance frequency and identify dominant loss mechanisms in different vibrational modes.
Krisztián Dubek, Christoph Schneidhofer, Nicole Dörr, and Ulrich Schmid
J. Sens. Sens. Syst., 13, 9–23, https://doi.org/10.5194/jsss-13-9-2024, https://doi.org/10.5194/jsss-13-9-2024, 2024
Short summary
Short summary
A new method for water detection in lubricated rail components is presented. It is based on a robust humidity sensor combined with robust data evaluation to determine the water content of greases. Based on a laboratory evaluation in the relevant environment, the presented approach offers an online monitoring tool to predict the water content of grease-lubricated rail parts, thereby enhancing the reliability and safety while reducing the maintenance costs and downtime of railway wagons.
Cited articles
Akasheh, F., Myers, T., Fraser, J. D., Bose, S., and Bandyopadhyay, A.: Development of piezoelectric micromachined ultrasonic transducers, Sensors and Actuators A: Physical, 111, 275–287, https://doi.org/10.1016/j.sna.2003.11.022, 2004.
Akhbari, S., Sammoura, F., Eovino, B., Yang, C., and Lin, L.: Bimorph Piezoelectric Micromachined Ultrasonic Transducers, Journal of Microelectromechanical Systems, 25, 326–336, https://doi.org/10.1109/JMEMS.2016.2516510, 2016.
Akhbari, S., Sammoura, F., Shelton, S., Yang, C., Horsley, D., and Lin, L.: Highly responsive curved aluminum nitride pMUT, 27th IEEE MEMS, 26–30 January 2014, 124–127, https://doi.org/10.1109/MEMSYS.2014.6765589, 2014.
Akhbari, S., Sammoura, F., Yang, C., Heidari, A., Horsley, D., and Lin, L.: Self-curved diaphragms by stress engineering for highly responsive pMUT, 28th IEEE MEMS, 18–22 January 2015, 837–840, https://doi.org/10.1109/MEMSYS.2015.7051089, 2015.
Baborowski, J., Ledermann, N., and Muralt, P.: Piezoelectric micromachined transducers (PMUT's) based on PZT thin films, 2002 IEEE Ultrasonics Symposium 2002 Proceedings, 8–11 Oct. 2002, vol. 1052, 1051–1054, doi:10.1109/ULTSYM.2002.1192475, 2002.
Bespalova, K., Osterlund, E., Ross, G., Paulasto-Krockel, M., Sebastian, A. T., Karuthedath, C. B., Mertin, S., and Pensala, T.: Characterization of AlScN-Based Multilayer Systems for Piezoelectric Micromachined Ultrasound Transducer (pMUT) Fabrication, Journal of Microelectromechanical Systems, 30, 290–298, https://doi.org/10.1109/jmems.2021.3056928, 2021.
Chen, B., Chu, F., Liu, X., Li, Y., Rong, J., and Jiang, H.: AlN-based piezoelectric micromachined ultrasonic transducer for photoacoustic imaging, Applied Physics Letters, 103, 031118, https://doi.org/10.1063/1.4816085, 2013.
Dausch, D. E., Gilchrist, K. H., Carlson, J. R., Castellucci, J. B., Chou, D. R., and Von Ramm, O. T.: Improved pulse-echo imaging performance for flexure-mode pMUT arrays, Proceedings – IEEE Ultrasonics Symposium, 451–454, https://doi.org/10.1109/ULTSYM.2010.5935826, 2010.
Dorfmeister, M., Schneider, M., and Schmid, U.: Static and dynamic performance of bistable MEMS membranes, Sensors and Actuators A: Physical, 282, 259–268, https://doi.org/10.1016/j.sna.2018.09.038, 2018.
Dorfmeister, M., Schneider, M., and Schmid, U.: 3D characterisation of piezoelectric bistable MEMS membranes during switching, Sensors and Actuators A: Physical, 298, 111576, https://doi.org/10.1016/j.sna.2019.111576, 2019a.
Dorfmeister, M., Kössl, B., Schneider, M., Pfusterschmied, G., and Schmid, U.: Switching performance of bistable membranes activated with integrated piezoelectric thin film transducers, Journal of Micromechanics and Microengineering, 29, 105008, https://doi.org/10.1088/1361-6439/ab3185, 2019b.
Guedes, A., Shelton, S., Przybyla, R., Izyumin, I., Boser, B., and Horsley, D. A.: Aluminum nitride pMUT based on a flexurally-suspended membrane, 16th International Solid-State Sensors, Actuators and Microsystems Conference, 5–9 June 2011, 2062–2065, https://doi.org/10.1109/TRANSDUCERS.2011.5969223, 2011.
Hajati, A., Latev, D., Gardner, D., Hajati, A., Imai, D., Torrey, M., and Schoeppler, M.: Three-dimensional micro electromechanical system piezoelectric ultrasound transducer, Applied Physics Letters, 101, 253101, https://doi.org/10.1063/1.4772469, 2012.
Haller, M. I. and Khuri-Yakub, B. T.: A surface micromachined electrostatic ultrasonic air transducer, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 43, 1–6, https://doi.org/10.1109/58.484456, 1996.
Harne, R. L. and Wang, K. W.: Harnessing Bistable Structural Dynamics: For Vibration Control, Energy Harvesting and Sensing, John Wiley & Sons Ltd., https://doi.org/10.1002/9781119128052, 2017.
Jung, J., Lee, W., Kang, W., Shin, E., Ryu, J., and Choi, H.: Review of piezoelectric micromachined ultrasonic transducers and their applications, Journal of Micromechanics and Microengineering, 27, 113001, https://doi.org/10.1088/1361-6439/aa851b, 2017.
Liu, X., Chen, X., Le, X., Wang, Y., Wu, C., and Xie, J.: Reducing ring-down time of pMUTs with phase shift of driving waveform, Sensors and Actuators A: Physical, 281, 100–107, https://doi.org/10.1016/j.sna.2018.08.039, 2018.
Morris, D. J., Need, R. F., Anderson, M. J., and Bahr, D. F.: Enhanced actuation and acoustic transduction by pressurization of micromachined piezoelectric diaphragms, Sensors and Actuators A: Physical, 161, 164–172, https://doi.org/10.1016/j.sna.2010.05.028, 2010.
Mortada, M., Das, P. T., Schmid, U., and Schneider, M.: High-resolution parametric characterization of snap-through behaviour in bistable PiezoMEMS membranes, Sensors and Actuators A: Physical, 389, 116548, https://doi.org/10.1016/j.sna.2025.116548, 2025.
Muralt, P., Schmitt, D., Ledermann, N., Baborowski, J., Weber, P. K., Steichen, W., Petitgrand, S., Bosseboeuf, A., Setter, N., and Gaucher, P.: Study of PZT coated membrane structures for micromachined ultrasonic transducers [medical imaging], 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.01CH37263), 7–10 October 2001, vol. 902, 907–911 https://doi.org/10.1109/ULTSYM.2001.991867, 2001.
Nayak, B., Gupta, H., Roy, K., Ashok, A., Shastri, V., and Pratap, R.: An Experimental Study of the Acoustic Field of a Single-Cell Piezoelectric Micromachined Ultrasound Transducer (PMUT), 2020 5th IEEE International Conference on Emerging Electronics (ICEE), 26–28 November 2020, 1–4, https://doi.org/10.1109/ICEE50728.2020.9777041, 2020.
Przybyla, R. J., Shelton, S. E., Guedes, A., Izyumin, I. I., Kline, M. H., Horsley, D. A., and Boser, B. E.: In-Air Rangefinding With an AlN Piezoelectric Micromachined Ultrasound Transducer, IEEE Sensors Journal, 11, 2690–2697, https://doi.org/10.1109/JSEN.2011.2157490, 2011.
Przybyla, R. J., Tang, H. Y., Shelton, S. E., Horsley, D. A., and Boser, B. E.: 3D ultrasonic gesture recognition, Digest of Technical Papers – IEEE International Solid-State Circuits Conference, 210–211, https://doi.org/10.1109/ISSCC.2014.6757403, 2014.
Przybyla, R. J., Tang, H., Guedes, A., Shelton, S. E., Horsley, D. A., and Boser, B. E.: 3D Ultrasonic Rangefinder on a Chip, IEEE Journal of Solid-State Circuits, 50, 320–334, https://doi.org/10.1109/JSSC.2014.2364975, 2015.
Rayleigh, J. W. S.: The Theory of Sound, Dover Publications, New York, ISBN-10: 0486602923, ISBN-13: 978-0486602929, 1945.
Sammoura, F., Shelton, S., Akhbari, S., Horsley, D., and Lin, L.: A two-port piezoelectric micromachined ultrasonic transducer, Joint IEEE ISAF/IWATMD/PFM, 12–16 May 2014, 1–4, https://doi.org/10.1109/ISAF.2014.6923004, 2014.
Schneider, M., Dorfmeister, M., Moll, P., Kaltenbacher, M., and Schmid, U.: Bi-Stable Aluminum Nitride-Based Piezoelectric Micromachined Ultrasonic Transducer (PMUT), Journal of Microelectromechanical Systems, 29, 1–6, https://doi.org/10.1109/JMEMS.2020.3004243, 2020.
Schomburg, W. K.: Introduction to Microsystem Design, 2nd, Springer Berlin, Heidelberg, https://doi.org/10.1007/978-3-662-47023-7, 2015.
Suzuki, K., Higuchi, K., and Tanigawa, H.: A silicon electrostatic ultrasonic transducer, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 36, 620–627, https://doi.org/10.1109/58.39112, 1989.
Wang, Z., Zhu, W., Miao, J., Zhu, H., Chao, C., and Tan, O. K.: Micromachined thick film piezoelectric ultrasonic transducer array, Sensors and Actuators A: Physical, 130–131, 485–490, https://doi.org/10.1016/j.sna.2005.10.054, 2006.
Weekers, B., Billen, M., Haouari, R., and Rochus, V.: Design of a PMUT array for Multifrequency Imaging, 2021 22nd International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), https://doi.org/10.1109/eurosime52062.2021.9410846, 2021.
Yamashita, K., Katata, H., Okuyama, M., Miyoshi, H., Kato, G., Aoyagi, S., and Suzuki, Y.: Arrayed ultrasonic microsensors with high directivity for in-air use using PZT thin film on silicon diaphragms, Sensors and Actuators A: Physical, 97–98, 302–307, https://doi.org/10.1016/S0924-4247(02)00037-7, 2002.
Yamashita, K., Nishiumi, T., Arai, K., Tanaka, H., and Noda, M.: Intrinsic Stress Control of Sol-Gel Derived PZT Films for Buckled Diaphragm Structures of Highly Sensitive Ultrasonic Microsensors, Procedia Engineering, 120, 1205–1208, https://doi.org/10.1016/j.proeng.2015.08.802, 2015.
Short summary
Bistability is a mechanical phenomenon resulting in two stable, switchable states similar to a light switch. Micromachined piezoelectric bistable loudspeakers can utilize this effect to generate ultrasonic pulses with substantial loudness for applications such as distance measurements. In this work, we study different aspects of such a micromachined ultrasonic loudspeaker and demonstrate that such a device is feasible for ranging applications.
Bistability is a mechanical phenomenon resulting in two stable, switchable states similar to a...
Special issue