Acoustic resonator device with air-ring and temperature compensating layer

Abstract

A bulk acoustic wave (BAW) resonator device includes a substrate defining a cavity, a bottom electrode formed over the substrate and at least a portion of the cavity, a piezoelectric layer formed on the bottom electrode, and a top electrode formed on the piezoelectric layer. An air-wing and an air-bridge are formed between the piezoelectric layer and the top electrode, the air-wing having an inner edge that defines an outer boundary of an active region of the BAW resonator device. The BAW resonator device further includes a temperature compensation feature having positive temperature coefficient for offsetting at least a portion of a negative temperature coefficient of the piezoelectric layer. The temperature compensation feature extends outside the active region by a predetermined length.

Dependencies are inferred from the claim text.