Film bulk acoustic wave resonator (FBAR) having stress-relief

An acoustic resonator structure comprises: a substrate comprising a cavity having a plurality of sides; a first electrode disposed over the cavity; a first connection portion that connects to the first electrode over only one side of the plurality of sides of the cavity; a piezoelectric layer disposed over at least a portion of the first electrode; a second electrode disposed over the piezoelectric layer; and a second connection portion that connects to the second electrode over only the one side of the plurality of sides. The second connection portion does not overlap the first connection portion, and a contacting overlap of the first electrode, the piezoelectric layer and the second electrode provides an active area of the acoustic resonator.