| 摘要 |
<p>A surface acoustic wave in which frequency/temperature characteristics can be improved effectively while the narrowing of a proportional band and the deterioration of insertion loss are not incurred significantly. In the surface acoustic wave device (1), at least one IDT electrode (3) is formed on a piezoelectric substrate (2), and an insulator layer (6) for improving the temperature characteristics is provided to cover the IDT electrode (3). When the surface of the insulator layer (6) is sectioned into a first surface region where the IDT electrode is located below and a second surface region where the IDT electrode is not located below, the height of surface of the insulator layer in at least a part of the second surface region is set to be larger by 0.001U or more than the height of surface of the insulator layer from the piezoelectric substrate (2) in at least a part of the first surface region, where U is the wavelength of surface acoustic wave.</p> |
