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Propagation characteristics of surface acoustic waves(SAWs) in ZnO films/glass substrates are theoretically investigated by the three-dimensional(3D) finite element method. At first, for(11ˉ20) ZnO films/glass substrates, the simulation results confirm that the Rayleigh waves along the [0001] direction and Love waves along the [1ˉ100] direction are successfully excited in the multilayered structures. Next, the crystal orientations of the ZnO films are rotated, and the influences of ZnO films with different crystal orientations on SAW characterizations, including the phase velocity, electromechanical coupling coefficient, and temperature coefficient of frequency, are investigated. The results show that at appropriate h/λ, Rayleigh wave has a maximum k~2 of 2.4% in(90°, 56.5°, 0°) ZnO film/glass substrate structure; Love wave has a maximum k~2 of 3.81% in(56°, 90°, 0°) ZnO film/glass substrate structure. Meantime, for Rayleigh wave and Love wave devices, zero temperature coefficient of frequency(TCF) can be achieved at appropriate ratio of film thickness to SAW wavelength. These results show that SAW devices with higher k~2 or lower TCF can be fabricated by flexibly selecting the crystal orientations of ZnO films on glass substrates.
Propagation characteristics of surface acoustic waves (SAWs) in ZnO films / glass substrates are theoretically investigated by the three-dimensional (3D) finite element method. At first, for (11ˉ20) ZnO films / glass substrates, the simulation results confirm that the Rayleigh Next, the crystal orientations of the ZnO films are rotated, and the influences of ZnO films with different crystal orientations on SAW characterizations, including the phase velocity, electromechanical coupling coefficient, and temperature coefficient of frequency, are investigated. The results show that at appropriate h / λ, Rayleigh wave has a maximum k ~ 2 of 2.4% in (90 °, 56.5 °, 0 °) Meantime, for Rayleigh wave and Love wave devices, zero temperature coefficiencies (ZnO), ZnO film / glass substrate structure; Love wave has maximum k ~ 2 of 3.81% in (56 °, 90 °, These results show that SAW devices with higher k ~ 2 or lower TCF can be fabricated by flexibly selecting the crystal orientations of ZnO films on glass substrates.