Piezoelectric thin film resonator and devices provided with the same

• Main Authors: YASUMOTO TAKAAKI, SANO KENYA, KAWAKUBO TAKASHI, YANASE NAOKO, OHARA RYOICHI, ITAYA KAZUHIKO
• Format: Patent
• Language: English
• Published: 14.12.2006
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

A piezoelectric thin film resonator includes a substrate in which a cavity is formed, a first electrode having a first electrode edge and partly spanning the cavity on the substrate; a piezoelectric layer placed on the first electrode, a second electrode having a second electrode edge and placed on the piezoelectric layer, a resonator unit constituted by an overlapping part of the first electrode, the piezoelectric layer, the second electrode, and the cavity; and a second lead wiring which is integral with the second electrode, extends to the substrate where the cavity is not present, and has a width larger than a part of a peripheral length of the cavity to which the second electrode edge extends. In the piezoelectric thin film resonator, a first length defined by the periphery of the first electrode of the resonator unit is larger than a second length defined by the second electrode edge of the resonator unit.