Bulk acoustic resonator structures with improved edge frames

A bulk acoustic wave (BAW) resonator includes a substrate, a stack over the substrate and including a piezoelectric layer disposed between two electrode layers, and one or more edge frames. The one or more edge frames can be a raised metal frame extending parallel to a periphery of an active region of the stack and has one or more slanted cuts such that the edge frame does not form a closed loop and loss of acoustic energy in the active region through the one or more cuts is reduced, minimized or prevented. Alternatively or additionally, the one or more edge frames include a recessed edge frame in the form of a trench in the piezoelectric layer extending parallel to a boundary of the active region, and may further include a second edge frame formed on the first electrode and embedded in the piezoelectric layer.