Quasi-Shear Mode Electromechanical Coupling Coefficient of c-Axis Tilted MgZnO Thin Films

Yohkoh Shimano, Hiroki Kishi, Shinya Kudo, Takahiko Yanagitani

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Thickness-shear mode piezoelectric thin films with high electromechanical coupling coefficient k^{\prime}{}-{35}^{2} are attractive for quasi-shear mode FBAR and shear horizontal (SH)-type SAW devices. In 2007, our group reported k^{\prime}{}-{35}^{2}= 6.8\% for a polycrystalline ZnO film with a 23° tilt to the surface normal. Furthermore, in 2020, our group reported that Mg-substituted ZnO significantly improves thickness-extensional mode k-{t}^{2}. In this study, we report the fabrication of c-axis tilted MgZnO films. By using Mason's equivalent circuit model including both quasi-shear mode and thickness-extensional mode, quasi-shear mode electromechanical coupling coefficient k^{\prime}{}-{35}^{2} and thickness-extensional mode electromechanical coupling coefficient k^{\prime}{}-{t}^{2} were estimated to be 5.0% and 0.97%, respectively. The resonator excites not only fundamental mode but also 2nd overtone mode because of an existence of a piezoelectrically inactive layer. Therefore, Mason's model including piezoelectrically inactive layer showed good agreement with the experimental data.

Original languageEnglish
Title of host publicationIUS 2022 - IEEE International Ultrasonics Symposium
PublisherIEEE Computer Society
ISBN (Electronic)9781665466578
Publication statusPublished - 2022
Event2022 IEEE International Ultrasonics Symposium, IUS 2022 - Venice, Italy
Duration: 2022 Oct 102022 Oct 13

Publication series

NameIEEE International Ultrasonics Symposium, IUS
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727


Conference2022 IEEE International Ultrasonics Symposium, IUS 2022


  • electromechanical coupling coefficient k'35
  • MgZnO
  • quasi-shear mode
  • thin film

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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