Chen Yoshimura LLP
Piezoelectric thin film resonator, filter, and duplexer
A piezoelectric thin film resonator includes: an acoustic reflection layer including an air gap or an acoustic mirror; lower and upper electrodes facing each other in a stacking direction, at least a part of each of the lower and upper electrodes being located on or above the acoustic reflection layer; a piezoelectric film sandwiched between the lower and upper electrodes and including lower and upper piezoelectric films, at least a part of an end face of the piezoelectric film in a film thickness direction being located between outer outlines of the resonance region and the acoustic reflection layer in at least a part of a region surrounding a resonance region; and an insertion film inserted between the lower and upper piezoelectric films, located in at least a part of an outer peripheral region within the resonance region, and not located in a center region of the resonance region.
TAIYO YUDEN CO., LTD.
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Jiansong Hiroomi Tsuyoshi Tokihiro Shinji
Liu Kaneko Yokoyama Nishihara Taniguchi