PIEZOELECTRIC THIN FILM RESONANT ELEMENT AND CIRCUIT COMPONENT USING THE SAME

摘要

A piezoelectric thin film resonant element (1) is provided with a resonant section comprising a laminated structure of a lower electrode (3) having an oval plane shape and a tilted portion (3a) tilted at a predetermined angle in the outer periphery, an upper electrode (5) having an oval plane shape, and a piezoelectric film (4) that is sandwiched between both electrodes. An additional film (8) is provided at a part of the location of the upper electrode (5) opposed to the tilted portion (3a) of the lower electrode (3). Thereby, a part of the laminate thickness (Hc) among the laminate thickness at the tilted portion (3a) of the lower electrode (3) at the resonant section is thicker than the laminate thickness (HA) at the inner portion than the tilted portion (3a) of the lower electrode (3) at the resonant section.