BAW resonator having lateral energy confinement and methods of fabrication thereof

摘要

Embodiments of a Bulk Acoustic Wave (BAW) resonator in which an outer region of the BAW resonator is engineered in such a manner that lateral leakage of mechanical energy from an active region of the BAW resonator is reduced, and methods of fabrication thereof, are disclosed. In some embodiments, a BAW resonator includes a piezoelectric layer, a first electrode on a first surface of the piezoelectric layer, a second electrode on a second surface of the piezoelectric layer opposite the first electrode, and a passivation layer on a surface of the second electrode opposite the piezoelectric layer, the passivation layer having a thickness (T_PA). The BAW resonator also includes a material on the second surface of the piezoelectric layer adjacent to the second electrode in an outer region of the BAW resonator. The additional material has a thickness that is n times the thickness (T_PA) of the passivation layer.