FILM BULK ACOUSTIC RESONATOR, OSCILLATOR, AND TIME STANDARD

摘要

PROBLEM TO BE SOLVED: To provide a film bulk acoustic resonator capable of having a high Q-value and suppressing oxidization of an electrode, and an oscillator and a time standard which use the film bulk acoustic resonator.

SOLUTION: In the present invention, there is provided an FBAR 100 including: a substrate 10; a lower electrode 12 containing copper as a main component; a piezoelectric thin film 14 disposed on the lower electrode 12 and containing aluminum nitride as a main component; an upper electrode 16 disposed on the piezoelectric thin film 14 so as to face the lower electrode 12 across the piezoelectric thin film 14 and containing copper as a main component; and a coating film covering one of a lower surface of the lower electrode 12 and an upper surface of the upper electrode 16. The thickness of the coating film 24 is smaller than a 1/4 of a wavelength of a bulk wave which propagates on the coating film 24. There are also provided an oscillator and a time standard using the film bulk acoustic resonator.

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