摘要 |
PROBLEM TO BE SOLVED: To improve reliability in moisture resistance/corrosion resistance of an SAW device (IDT electrode). SOLUTION: The SAW device is provided with: a piezoelectric substrate; an IDT provided on the piezoelectric substrate and formed of Al or an Al alloy; and a protective film for covering at least one part of the piezoelectric substrate and the IDT. The protective film contains: a metal oxide layer which is formed on at least one part of the piezoelectric substrate and the surface of the IDT, is a continuous film on the IDT surface, and is a discontinuous film on the piezoelectric substrate surface; and a silicon dioxide layer formed on the metal oxide layer. Preferably, the piezoelectric substrate is a single crystalline piezoelectric substrate, the metal oxide layer contains an oxide (e.g. chrome oxide) of a transition metal, the silicon dioxide layer has a thickness of not more than 10 nm, and the metal oxide layer has a thickness of not more than 2 nm. COPYRIGHT: (C)2007,JPO&INPIT
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