| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave device not only including electrode protecting effect and temperature characteristic improving effect due to an SiO<SB>2</SB>film but also being capable of suppressing deterioration of an insertion loss. SOLUTION: At least one IDT 13a, 13b comprised of Al or a metal mainly containing Al is formed on a piezoelectric substrate 12 comprised of rotary Y-cut X-propagation LiTaO<SB>3</SB>, an SiO<SB>2</SB>film 15 is formed to cover the IDT 13a, 13b, and the combination of standardized film thickness Hs of the SiO<SB>2</SB>film and a cut angleθof the piezoelectric substrate comprised of LiTaO<SB>3</SB>is selected within a predetermined range. Thus, an attenuation constant of a surface acoustic wave can be reduced while maintaining temperature characteristic improving effect, thereby reducing the insertion loss. COPYRIGHT: (C)2006,JPO&NCIPI
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