PIEZOELECTRIC THIN FILM RESONATOR AND FILTER

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric thin film resonator and a filter, which suppress a lateral direction leak of elastic waves and making loss low.

SOLUTION: The piezoelectric thin film resonator and the filter comprises: a substrate (10); a lower electrode (12) arranged on the substrate; a piezoelectric film (14) arranged on the lower electrode; and an upper electrode (16) arranged on the piezoelectric film and having a portion (22) facing the lower electrode across the piezoelectric film. It is characterized in that at least a part of the perimeter at the facing portion of the piezoelectric film is arranged inside from the perimeter of region (R) where the upper electrode faces the lower electrode.

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