Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers

Halbach, Chloé; Rochus, Veronique; Genoe, Jan; Rottenberg, Xavier; Cheyns, David; Heremans, Paul

doi:10.3390/mi16020160

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Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers

by

Chloé Halbach

^1,2,*

,

Veronique Rochus

¹,

Jan Genoe

^1,2

,

Xavier Rottenberg

¹,

David Cheyns

¹ and

Paul Heremans

^1,2

¹

Interuniversity Microelectronics Centre, Kapeldreef 75, 3001 Leuven, Belgium

²

Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium

^*

Author to whom correspondence should be addressed.

Micromachines 2025, 16(2), 160; https://doi.org/10.3390/mi16020160

Submission received: 29 December 2024 / Revised: 17 January 2025 / Accepted: 23 January 2025 / Published: 29 January 2025

(This article belongs to the Special Issue MEMS Ultrasonic Transducers)

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Abstract

The pull-in and pull-out voltages are important characteristics of Capacitive Micromachined Ultrasound Transducers (CMUTs), marking the transition between conventional and collapse operation regimes. These voltages are commonly determined using capacitance–voltage (C-V) sweeps. By modeling the operating conditions of an LCR meter in COMSOL Multiphysics^®, we demonstrate that the measured capacitance comprises both static and dynamic capacitances, with the dynamic capacitance causing the appearance of a peak in the effective C-V curve. Furthermore, Laser Doppler Vibrometer (LDV) measurements and electromechanical simulations indicate the occurrence of collapse–snapback phenomena during the C-V sweeps. This study, through advanced simulations and experimental analyses, demonstrates that the transient membrane behavior significantly affects the apparent capacitance–voltage characteristics of electrostatically actuated Micro-Electromechanical Systems (MEMS).

Keywords: capacitance–voltage characteristics; dynamic capacitance; electrostatic pull-in; LCR meter; Laser Doppler Vibrometer; COMSOL Multiphysics simulations

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MDPI and ACS Style

Halbach, C.; Rochus, V.; Genoe, J.; Rottenberg, X.; Cheyns, D.; Heremans, P. Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers. Micromachines 2025, 16, 160. https://doi.org/10.3390/mi16020160

AMA Style

Halbach C, Rochus V, Genoe J, Rottenberg X, Cheyns D, Heremans P. Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers. Micromachines. 2025; 16(2):160. https://doi.org/10.3390/mi16020160

Chicago/Turabian Style

Halbach, Chloé, Veronique Rochus, Jan Genoe, Xavier Rottenberg, David Cheyns, and Paul Heremans. 2025. "Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers" Micromachines 16, no. 2: 160. https://doi.org/10.3390/mi16020160

APA Style

Halbach, C., Rochus, V., Genoe, J., Rottenberg, X., Cheyns, D., & Heremans, P. (2025). Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers. Micromachines, 16(2), 160. https://doi.org/10.3390/mi16020160

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

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Analysis of Collapse–Snapback Phenomena in Capacitive Micromachined Ultrasound Transducers

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