Acoustic resonator comprising temperature compensating layer and perimeter distributed bragg reflector

摘要

An acoustic resonator structure includes a bottom electrode disposed on a substrate, a piezoelectric layer disposed on the bottom electrode, a top electrode disposed on the piezoelectric layer, a cavity disposed beneath the bottom electrode, and a temperature compensating feature. The temperature compensating feature has a positive temperature coefficient for offsetting at least a portion of a negative temperature coefficient of the piezoelectric and electrode layers. The acoustic resonator structure further includes an acoustic reflector disposed over the substrate around a perimeter of the cavity. The acoustic reflector includes a layer of low acoustic impedance material stacked on a layer of high acoustic impedance material.