超音波診断用CMUTの積層薄膜構造の検討

カテゴリ: 論文誌(論文単位)

グループ名: 【E】センサ・マイクロマシン部門

発行日: 2017/10/01

タイトル(英語): Evaluation of Thin Films Composition of Capacitive Micromachined Ultrasonic Transducers for Ultrasonic Diagnoses

著者名: 青野　宇紀（（株）日立製作所 研究開発グループ 機械イノベーションセンタ），吉村　保廣（（株）日立製作所 研究開発グループ 機械イノベーションセンタ），町田　俊太郎（（株）日立製作所 研究開発グループ エレクロトニクスイノベーションセンタ）

著者名(英語): Takanori Aono (Center for Technology Innovation - Mechanical Engineering, Research and Development Group, Hitachi, Ltd.), Yasuhiro Yoshimura (Center for Technology Innovation - Mechanical Engineering, Research and Development Group, Hitachi, Ltd.), Shuntaro Machida (Center for Technology Innovation - Electronics, Research and Development Group, Hitachi, Ltd.)

キーワード: 超音波探触子，CMUT，薄膜，応力，有限要素法　　ultrasonic probe，capacitive micromachined ultrasonic transducers，thin film，stress，finite element method

要約(英語): This research reports thin films composition of vibrating film on capacitive micromachined ultrasonic transducers (CMUT) for ultrasonic diagnoses. The CMUT constitutes an electrostatically vibrating film, which is fabricated by deposition processes of SiO2 and SiN films as insulator and TiN and Al films as top electrode on an Si substrate. The ultrasonic waves are transmitted by addition of AC voltage between the top electrode of vibrating film and the Si substrate, whereas the reflective ultrasonic wave are received with the vibrating film and converted to the electrical signals for ultrasonic diagnostic images. When the vibrating film is initially deformed by an internal stress of the stacked thin films, the transmitting strength of ultrasonic waves and the capacitance change by receiving reflective ultrasonic waves are not enough to achieve a high sensitivity. Thus, the thickness of SiO2 and SiN films was analytically and experimentally determined to achieve the flat vibrating film. Accordingly, a 300-nm-thick SiO2 film with a compressive stress of 150 MPa and a 1700-nm-thick SiN film with a tensile stress of 100 MPa were decided as one proper films composition. Also, the prototype CMUT can acquire an image of sponge simulated a test body.

本誌: 電気学会論文誌E（センサ・マイクロマシン部門誌） Vol.137 No.10 （2017） 特集：バイオマイクロシステムの基礎と応用

本誌掲載ページ: 341-348 p

原稿種別: 論文／日本語

電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejsmas/137/10/137_341/_article/-char/ja/