Polarization inverted two layer ScAlN thin film resonator fabricated by applying external electric field

Naoki Ishii, Takahiko Yanagitani

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


ScAlN has high piezoelectricity and ferroelectricity. BAW filters with polarization inverted multilayer structure allow the further improvement of the power durability. In this study, by growing the Al-polar ScAIN film on the N-polar film, the polarization inverted two-layer ScAIN thin films resonator were fabricated. Unusual N-polar ScAIN film was obtained by a polarization inversion treatment to the as-grown usual Al-polar films. Polarity of the ScAlN films was determined by a press test. kt2 of as-grown Al-polar ScAIN and N-polar ScAlN films after the polarization treatment (-190 V (2.0 MV/cm) at 300 °C) were estimated to be 7.7% and 5.6%, respectively. Because of an incomplete polarization inversion, kt2 in the film after polarization inversion treatment slightly decreased compared with the as-grown films. Second overtone mode excitation was observed at GHz range, and fundamental mode was suppressed.

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


  • BAW
  • ferroelectric
  • polarization inverted multilayer
  • ScAIN

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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