| 摘要 |
PROBLEM TO BE SOLVED: To provide a piezoelectric thin-film device of which characteristics are improved. SOLUTION: In a piezoelectric thin-film filter 1 including four piezoelectric thin-film resonators R11-R14, a filter section 11, which provides the filter function of the piezoelectric thin-film filter 1, is adhered to a flat base substrate 13, which supports the filter section 11 mechanically, via an adhesive layer 12. In the piezoelectric thin-film filter 1, a piezoelectric body thin film 119 is adhered to the base substrate 13 via a cavity formation film 114 formed in a non-excitation region E1X in the piezoelectric body thin film 111, thus retaining excitation regions E11-E14 of the piezoelectric body thin film 111 in the air without any control, and preventing the upper and lower surfaces of the excitation regions E11-E14 from coming into contact with other portions. COPYRIGHT: (C)2007,JPO&INPIT
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