| 摘要 |
PROBLEM TO BE SOLVED: To provide a thin film bulk wave resonator for suppressing deterioration in the resonance characteristic and obtaining a high resonance frequency by increasing an electrode area of the thin film bulk wave resonator. SOLUTION: The thin film bulk wave resonator is provided with an upper electrode 104, a lower electrode 102, and a piezoelectric film 103 and a sound multilayer film 120 located between the upper electrode 104 and the lower electrode 102. Since the distance between the upper electrode 104 and the lower electrode 102 is extended by the thickness of the sound multilayer film 120, the static capacitance per unit area between the upper electrode 104 and the lower electrode 102 can be decreased. Thus, the electrode area can be increased more in comparison with the case with absence of the sound multilayer film 120 and it is possible to reduce the effect of grain of a piezoelectric material. COPYRIGHT: (C)2005,JPO&NCIPI
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