| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric thin film resonator with a wide band width and a wide oscillating frequency range when it is applied to a resonator, a filter or the like and having a large electromechanical coupling coefficient. SOLUTION: This resonator is provided with a single crystal substrate 3, a piezoelectric thin film 2 formed on the single crystal substrate 3 and two electrodes 1 made of a conductive film formed on the piezoelectric thin film 2. In this case, the piezoelectric thin film 2 is made of e.g. lead zirconate titanate (PZT) or lead titanate (PT) thin film whose the thickness is 0.1-10μm formed by a sol-gel method, an electric field is applied between the two electrodes 1 to apply polarization processing and to make the piezoelectric thin film. As required, an interval between the two electrodes 1 is made to 0.5-10μm and a part of a rear side of the single crystal substrate is removed by etching.
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