| 摘要 |
Provided is a surface acoustic wave device in which a temperature characteristic of frequency can be effectively improved without a significant narrowing of a fractional bandwidth and a significant insertion loss. A surface acoustic wave device 1 includes a piezoelectric substrate 2, at least one interdigital transducer (IDT) electrode 3 formed on the piezoelectric substrate 2, and an insulator layer 6 for improving a temperature characteristic formed so as to cover the IDT electrode 3. When a surface of the insulator layer 6 is classified into a first surface region under which the IDT electrode is positioned and a second surface region under which no IDT electrode is positioned, the surface of the insulator layer in at least one portion of the second surface region is higher than the surface of the insulator layer from the piezoelectric substrate 2 in at least one portion of the first surface region by 0.001» or more, where the wavelength of an acoustic wave is ». |
