| Project/Area Number |
11305025
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKAMURA Kiyoshi Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (00005365)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Ken Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (80134021)
姜 煕復 東北大学, 大学院・工学研究科, 助手 (20302185)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥28,500,000 (Direct Cost: ¥28,500,000)
Fiscal Year 2000: ¥8,500,000 (Direct Cost: ¥8,500,000)
Fiscal Year 1999: ¥20,000,000 (Direct Cost: ¥20,000,000)
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| Keywords | Piezoelectric Resonator / Acoustic Multilayers / ZnO / LiTaO_3 Crytal / MBE / Thin Film Resonator / ZnO薄膜 |
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| Research Abstract |
The purpose of this study is to investigate a new piezoelectric thin film resonator using acoustic λ/4 multilayers, which is promising for use in a very high frequency range from 1 to 20GHz and can be incorporated within integrated circuits. The main results of this study are summarized below.
1. The λ/2 mode configuration of piezoelectric thin film resonator using acoustic λ/4 multilayers, where the piezoelectric film is λ/2 thick, was analyzed in consideration of propagation loss, and then electrical quality factor Q and effective electromechanical coupling factor K were calculated as functions of the acoustic impedance ratio of multilayers and the layer number.
2. The quality of c-axis oriented piezoelectric ZnO films grown by ECR-assisted MBE were evaluated with RHEED and X-ray diffraction. It has been confirmed that high quality ZnO single crystal films can be grown.
3. A new simple evaluation method for acoustic properties, such as density and stiffness, of thin films was proposed. In this method, the acoustic properties are evaluated from the measured resonance frequency change of high overtones of a piezoelectric thickness-mode resonator due to deposition of a test film on the resonator surface.
4. Dispersion characteristics of elastic waves which propagate along the surface being trapped in a piezoelectric film were analyzed. It has been shown that a vibration trapped in the finite electroded region can be occurred.
5. A 3-GHz piezoelectric ZnO film resonator with five λ/4 acoustic multilayers was fabricated on a Z-cut LiTaO_3 substrate and this type of resonators were shown to be promising for use in a very high frequency range from 1 to 20GHz.
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