| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic surface wave device which has an insulating film arranged so as to cover an electrode film, is immune to deterioration of resonance characteristics, filter characteristics due to generation of the insulating film, and does not require a complex manufacturing process. SOLUTION: In the acoustic surface wave device, the electrode films constituting at least one IDT 3 are disposed on a piezoelectric substrate 2, and a SiO<SB>2</SB>film 5 is formed on the piezoelectric substrate 2 so as to cover the electrode films, and a film-thickness of the electrode films is in the range between 1% and 3% of a wavelength of an excited acoustic surface wave. The acoustic surface wave device comprises the piezoelectric substrate, the electrode films formed on the electric substrate and constituting at least one IDT, and the insulating film with projection and recess portions on the upper surface thereof, which is formed on the piezoelectric substrate by sputtering so as to cover the electrode films, in which the film-thickness of the electrode films is in the range between 1% and 3% of the wavelength of the excited acoustic surface wave. COPYRIGHT: (C)2004,JPO&NCIPI
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