A Method for Extracting Mechanical Q Factor of the Piezoelectric Film without Etching Substrate

Sarina Kinoshita, Takahiko Yanagitani

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

Abstract

The sharpness of FBAR filters are determined by mechanical Q factors (Qm) of piezoelectric thin films when other electrical loss is negligibly small. In this study, we introduce a new method for estimating Qm of films using piezoelectric film/substrate structures (HBAR structures) without using self-standing film structures. When Qm of the film (Qpiezo) is lower than that of the substrate (Qsub), Q factor of the entire HBAR (QHBAR) decrease due to the dumping of the film which have larger mechanical loss, only in the vicinity of the resonant frequency. Therefore, Qpiezo can be estimated from the amount of reduction in the QHBAR when Qsub is known. We investigated whether the differences of the Qm factor among various samples are able to be detected. Obvious decrease of experimental QHBAR in the vicinity of the resonant frequency of each film was observed as expected. The amount of reduction of ScAlN is larger than that of pure AlN, indicating that mechanical Qpiezo of ScAlN is lower than that of pure AlN as expected.

Original languageEnglish
Title of host publication2019 IEEE International Ultrasonics Symposium, IUS 2019
PublisherIEEE Computer Society
Pages299-300
Number of pages2
ISBN (Electronic)9781728145969
DOIs
Publication statusPublished - 2019 Oct
Event2019 IEEE International Ultrasonics Symposium, IUS 2019 - Glasgow, United Kingdom
Duration: 2019 Oct 62019 Oct 9

Publication series

NameIEEE International Ultrasonics Symposium, IUS
Volume2019-October
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Conference

Conference2019 IEEE International Ultrasonics Symposium, IUS 2019
CountryUnited Kingdom
CityGlasgow
Period19/10/619/10/9

Keywords

  • FBAR
  • mechanical Q
  • piezoelectric material

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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    Kinoshita, S., & Yanagitani, T. (2019). A Method for Extracting Mechanical Q Factor of the Piezoelectric Film without Etching Substrate. In 2019 IEEE International Ultrasonics Symposium, IUS 2019 (pp. 299-300). [8926088] (IEEE International Ultrasonics Symposium, IUS; Vol. 2019-October). IEEE Computer Society. https://doi.org/10.1109/ULTSYM.2019.8926088