| 摘要 |
PROBLEM TO BE SOLVED: To improve the junction strength of each layer contained in an electrode and that of an annular electrode and a piezoelectric substrate, and to suppress corrosion of the electrode. SOLUTION: A surface acoustic wave device has a circuit board, and a surface acoustic wave element mounted on the circuit board by a wire-bonding system. The surface acoustic wave element comprises an excitation electrode, formed on a main surface 1a of the piezoelectric substrate 1; and the annular electrode 11, that is formed on the main surface 1a of the piezoelectric substrate 1 and is formed at a position of surrounding the outer periphery of the excitation electrode. The annular electrode 11 includes an underlayer 12, formed on the main surface 1a of the piezoelectric substrate 1 by a metal material with Al as the main constituent; an adhesive electrode layer 13, formed at a position of covering the underlayer 12; and a barrier metal electrode layer 14 formed on the adhesive electrode layer 13. A protective film 10 is also provided on the main surface 1a at the periphery of the annular electrode 11, and is formed to be thicker than the adhesive electrode layer 13. COPYRIGHT: (C)2007,JPO&INPIT
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