A surface acoustic wave device has a piezoelectric substrate having a cut angle (e.g., the piezoelectric angle is cut so as to have a crystal orientation) that allows the surface acoustic wave device to operate as a longitudinally leaky surface acoustic wave device that confines the acoustic wave energy within the piezoelectric substrate and that has less propagation attenuation and a higher electromechanical coupling coefficient k.sup.2.

Disclosed are methods of preparing a Surface Acoustic Wave (SAW) device, comprising: sequentially depositing a Cu electrode, a silicon oxide film, modifying the surface of the silicon oxide film, and then depositing a piezoelectric film, and an Al electrode on a substrate having an interdigital (IDT) electrode pattern to obtain the SAW device. In some embodiments, the Cu and Al electrodes both have IDT electrode patterns corresponding to the IDT pattern of the substrate. Because the Sezawa wave mode that is adopted is formed by coupling film thickness vibration and transverse vibration, the present invention is characterized in that a longitudinal electric field and a transverse electric field are excited through the double-layer electrodes whereby the electromechanical coupling coefficient of the SAW device can be improved by changing the coupling pattern between the electric fields and the piezoelectric film.

A method of manufacturing a surface acoustic wave resonator includes forming or providing a support substrate layer, forming or providing piezoelectric layer of lithium niobate over the support substrate layer, and forming or providing an interdigital transducer electrode including a plurality of fingers over the piezoelectric layer. The piezoelectric layer formed or provided having a cut angle (e.g., the piezoelectric angle is cut so as to have a crystal orientation) that allows the surface acoustic wave device to operate as a longitudinally leaky surface acoustic wave device that confines the acoustic wave energy within the piezoelectric substrate and that has less propagation attenuation and a higher electromechanical coupling coefficient k.sup.2.