PIEZOELECTRIC THIN-FILM RESONATOR AND FILTER USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a resonator having excellent characteristics and a filter composed by combining a plurality of the resonators without forming an upper electrode or a lower electrode connected to a membrane into a prescribed shape.

SOLUTION: The piezoelectric thin-film resonator is provided with a composite film having the lower electrode 43 formed on a substrate 41, a piezoelectric film 44 formed on the substrate 41 and the lower electrode 43, and the upper electrode 45 formed on the piezoelectric film 44. A shape of a lead-out from the membrane 46 is made thinner than the contour width of the membrane 46, in at least one of the upper electrode and the lower electrode connected to the membrane 46 of a region where the upper electrode 45 and the lower electrode 43 sandwiching the piezoelectric film 44 are overlapped.

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