Development of HfO2-based ferroelectric films for Piezo MEMS applications

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K19016
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 29:Applied condensed matter physics and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Funakubo Hiroshi 東京工業大学, 物質理工学院, 教授 (90219080)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: 酸化ハフニウム基強誘電体 / 圧電性

Outline of Final Research Achievements

This study tries to grow thick ferroelectric HfO2 films for Piezo MEMS applications. 1 micrometer-thick ferroelectric HfO2-based films were successfully grown. Ferroelectric property of these films was almost independent of the film thickness. Moreover, epitaxial films with {100} orientation were obtained on (100)ITO//(100)YSZ and (100)ITO//(100)YSZ/(100)Si substrates. Piezoresponse of these films was 2-3 pm/V. Finally, a micrometer -thick ferroelectric films were obtained even by room temperature deposition.

Free Research Field

無機機能材料

Academic Significance and Societal Importance of the Research Achievements

HfO2はトランジスターのゲート酸化物で実用になっており、Si基の半導体プロセスと高い親和性を有する。従来の圧電体はこのプロセスとの親和性が低く、圧電MEMSの実用化はなかなか進んでこなかった。本研究によって、HfO2基の強誘電体が圧電MEMSで必要な１μmまでの厚膜化が実現できたこと、室温プロセスが実現できたことは、圧電MEMSへのHfO2の応用の可能性を開いた研究と言え、その社会的意義は大きい。