SURFACE ACOUSTIC WAVE DEVICE

摘要

A surface acoustic wave device (1) excellent in power resistance in which unwanted spurious can be suppressed effectively. The surface acoustic wave device (1) comprises an LiNbO<SUB>3</SUB> substrate (2) having an Euler angle (0°±5°, ?±5°, 0°±10°), an electrode formed on the LiNbO<SUB>3</SUB> substrate and including an IDT electrode (3) principally comprising Cu, a first silicon oxide film (6) formed to have a thickness equal to that of the electrode in the region other than the region where the electrode is formed, and a second silicon oxide film (7) so formed as to cover the electrode and the first silicon oxide film. The surface acoustic wave device (1) utilizes an SH wave, the duty D of the IDT electrode (3) is 0.49 or less, and the ? in the Euler angle (0°±5°, ?±5°, 0°±10°) falls within a range satisfying a predetermined formula (1).