Patent ID: 9490418
Filing Date: 2016-11-08
CPC Classification: H01L,H03H

Claim Text:
1. An acoustic resonator, comprising: an acoustic reflector disposed on a substrate over a cavity formed in the substrate, the acoustic reflector comprising a layer of low acoustic impedance material stacked on a layer of high acoustic impedance material; a bottom electrode disposed on the layer of low acoustic impedance material of the acoustic reflector; a piezoelectric layer disposed on the bottom electrode; a top electrode disposed on the piezoelectric layer; and a collar formed outside a main membrane region defined by an overlap between the top electrode, the piezoelectric layer and the bottom electrode, the collar having an inner edge substantially aligned with a boundary of or overlapping the main membrane region, wherein the layer of the low acoustic impedance material comprises a temperature compensating material 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.