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.

主权项

1. An acoustic resonator, comprising:
a perimeter acoustic reflector disposed on a substrate around a perimeter of a cavity, the perimeter acoustic reflector comprising a layer of low acoustic impedance material stacked on a layer of high acoustic impedance material; a bottom electrode disposed over the cavity and on at least a portion of the perimeter acoustic reflector; a piezoelectric layer disposed on the bottom electrode; a top electrode disposed on the piezoelectric layer; and a temperature compensating feature having a positive temperature coefficient for offsetting at least a portion of a negative temperature coefficient of the piezoelectric layer, the bottom electrode and the top electrode, wherein the cavity extends from the bottom electrode at least partially through the perimeter acoustic reflector, and ends within the perimeter acoustic reflector, at a top surface of the substrate or within the substrate, enabling vibration of at least a portion of the piezoelectric layer positioned over the cavity.