Theoretical Study on SAW Characteristics of Layered Structures Including a Diamond Layer

Hideaki Nakahata, Akihiro Hachigo, Kenjiro Higaki, Satoshi Fujii, Shin-ichi Shikata, and Naoji Fujimori

ABSTRACT Diamond has the highest surface acoustic wave (SAW) velocity among all materials and thus can provide much advantage for fabrication of high frequency SAW devices when it is combined with a piezoelectric thin film. Basic SAW properties of layered structures consisting of a piezoelectric material layer, a diamond layer and a substrate were examined by theoretical calculation. Rayleigh mode SAW's with large SAW velocities up to 12,000 m/s and large electro-mechanical coupling coefficients from 1 to 11% were found to propagate in ZnO/diamond/Si, LiNbO3/diamond/Si and LiTaO3/diamond/Si structures. It was also found that a SiO2/ZnO/diamond/Si structure can realize a zero temperature coefficient of frequency with a high phase velocity of 8,000-9,000 m/s and a large electro-mechanical coupling coefficient of up to 4%.

© 1995, by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.

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