| 摘要 |
A piezoelectric resonator includes; a lower electrode 24 formed on a substrate 11 ; a piezoelectric film 23 formed on the lower electrode 24 ; an upper electrode 25 formed on the piezoelectric film 23 and obtaining, in collaboration with the lower electrode 24 , a signal having a predetermined resonance frequency by a propagation of a bulk acoustic wave inside the piezoelectric film 23 ; and an acoustic multilayer reflective film 28 including an SiO<SUB>2 </SUB>film 28 a having a predetermined acoustic impedance and an AIN film 28 b having an acoustic impedance higher than the SiO<SUB>2 </SUB>film 28 a, and reflecting the bulk acoustic wave, the SiO<SUB>2 </SUB>film 28 a and the AIN film 28 b being alternately stacked on the upper electrode 25 , and the SiO<SUB>2 </SUB>film 28 a being in contact with the upper electrode 25.
|
