Patent ID: 11711064

Abstract:
An RF filter system includes a plurality of bulk acoustic wave resonators arranged in a circuit having serial and parallel shunt configurations of resonators. Each resonator having a reflector, a support member including a surface, a first electrode including tungsten, overlying the reflector, a piezoelectric film including crystalline aluminum scandium nitride overlapping the first electrode, a second electrode including tungsten overlapping the piezoelectric film and the first electrode, and a passivation layer including silicon nitride overlying the second electrode. Portions of the support member surface of at least one resonator define a cavity region having a portion of the first electrode of the at least one resonator is located within the cavity region. The pass band circuit response has a bandwidth corresponding to a thickness of at least one of the first electrode, piezoelectric film, second electrode, and passivation layer. The system can include single crystal or polycrystalline BAW resonators.