Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on 2010-01-01

Theoretical analysis of SAW propagation characteristics in (100) oriented AlN/diamond structure.

Ruyen Ro, Yuan-Feng Chiang, Chia-Chi Sung, Ruyue Lee, Sean Wu

Index: IEEE Trans. Ultrason. Ferroelectr. Freq. Control 57(1) , 46-51, (2010)

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Abstract

In this study, the finite element method is employed to calculate SAW characteristics in (100) AlN/diamond based structures with different electrical interfaces; i.e., IDT/ AlN/diamond, AlN/IDT/diamond, IDT/AlN/thin metal film/ diamond, and thin metal film/AlN/IDT/diamond. The effects of Cu and Al electrodes as well as the thickness of electrode on phase velocity, coupling coefficient, and reflectivity of SAWs are illustrated. Propagation characteristics of SAWs in (002) AlN/diamond-based structures are also presented for comparison. Simulation results show that to retain a large reflectivity for the design of RF filters and duplexers, the Cu IDT/(100) AlN/diamond structure possesses the highest phase velocity and largest coupling coefficient at the smallest AlN film thickness- to-wavelength ratio.