PIEZOELECTRIC RESONATOR AND PIEZOELECTRIC THIN FILM FILTER

摘要

There is provided a piezoelectric resonator and a piezoelectric thin-film filter including the piezoelectric resonator, the piezoelectric resonator being capable of suppressing long-wavelength spurious modes and short-wavelength spurious modes. The planar shape of a vibrating region 18 including a piezoelectric layer 15 disposed between a pair of conductive layers 14 and 16 is rectangle when viewed in the thickness direction. Outer edges 18a of the vibrating region 18 each have a waveform. The vibrating region 18 includes a peripheral portion 18t extending along the outer edges of the planar shape and having a relatively small thickness; and a central portion 18s extending inside the peripheral portion 18t and having a relatively large thickness.