Stable / Reliable Sensing and Precise Control of Piezoelectric Thin Film Actuators

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01390
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 20010:Mechanics and mechatronics-related
• Research Institution: Tohoku University
• Principal Investigator: Tanaka Shuji 東北大学, 工学研究科, 教授 (00312611)
• Co-Investigator(Kenkyū-buntansha): 吉田 慎哉 東北大学, 工学研究科, 特任准教授 (30509691) ; 塚本 貴城 東北大学, 工学研究科, 准教授 (70646413)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: MEMS / 圧電薄膜 / PZT / ピエゾ抵抗センサー / エピタキシャル成長 / 信頼性 / PMN-PT

Outline of Final Research Achievements

A new technology to apply buried silicon piezoresistive sensors to PZT piezo MEMS was demonstrated to improve the positioning accuracy and reliability of piezo MEMS actuators. Devices were fabricated and their scale factor and noise were evaluated. Also, the amplitude was controlled using the piezoresistive sensors.
In terms of epitaxial PZT family thin films, crack generation and breakdown, which were the most severe problems for reliability, were mainly studied. Their solutions were experimentally confirmed but accompanied with a penalty of piezoelectric performance. To obtain a better piezoelectricity, the epitaxial sputter-deposition of Sm-doped PMN-PT on silicon was also studied. A good piezoelectricity was finally obtained by a separate sputtering method using a PZT buffer layer.

Free Research Field

MEMS

Academic Significance and Societal Importance of the Research Achievements

PZT圧電MEMSアクチュエーターの新しい用途には，電圧をDC的にかけ，準静的変位を安定的に制御しなくてはならないものがある。これは従来の方式では難しいが，ここで開発した技術は上述の用途に適しており，PZT圧電MEMSの応用を広げるものである。
エピタキシャルPZT系薄膜は，次世代材料として期待されているが，信頼性に問題がある。また，従来材料の置き換えには圧倒的な性能も必要である。本研究は，これらの課題解決を一歩進めるものである。