High electromechanical coefficient kt2=19% thick ScAlN piezoelectric films for ultrasonic transducer in low frequency of 80 MHz

Ko Hei Sano, Rei Karasawa, Takahiko Yanagitani

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

7 Citations (Scopus)

Abstract

Ultrasonic transducers in the frequency ranges of 20-100 MHz is not well-developed because of less applications or less suitable piezoelectric materials. PVDF are usually used for ultrasonic transducers in the 10-50 MHz ranges. However, their electromechanical coupling coefficient kt2 of 4% is not enough for the practical uses. In order to excite ultrasonic in the 20-100 MHz, 125 μm-25 μm thick piezoelectric film is required. It is difficult to grow such a thick piezoelectric film without a crack caused by the internal stress during the PVD deposition technique. We achieved stress free film growth by employing the unique hot cathode sputtering technique without heating substrate. We demonstrated high efficient 81 MHz (kt2=18.5%) and 43 MHz (kt2=11.9%) ultrasonic generation by using the 43 μm and 90 μm extremely thick ScAlN(Sc:39%) films, respectively.

Original languageEnglish
Title of host publication2017 IEEE International Ultrasonics Symposium, IUS 2017
PublisherIEEE Computer Society
ISBN (Electronic)9781538633830
DOIs
Publication statusPublished - 2017 Oct 31
Event2017 IEEE International Ultrasonics Symposium, IUS 2017 - Washington, United States
Duration: 2017 Sep 62017 Sep 9

Publication series

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

Other

Other2017 IEEE International Ultrasonics Symposium, IUS 2017
Country/TerritoryUnited States
CityWashington
Period17/9/617/9/9

Keywords

  • ScAlN
  • Thick piezoelectric film
  • Ultrasonic transducers

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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