BULK ACOUSTIC RESONATOR DEVICE INCLUDING TEMPERATURE COMPENSATION STRUCTURE COMPRISING LOW ACOUSTIC IMPEDANCE LAYER

摘要

An acoustic resonator device includes a temperature compensation structure disposed beneath the first electrode and above the substrate.

主权项

1. A bulk acoustic wave (BAW) resonator, comprising:
a substrate comprising an acoustic reflector; a first electrode disposed over the substrate, the first electrode having a first acoustic impedance; a piezoelectric layer disposed over the first electrode; a second electrode disposed over the piezoelectric layer, the second electrode having a second acoustic impedance; and a temperature compensation structure disposed beneath the first electrode and above the substrate, the temperature compensation structure comprising: a first layer having a positive temperature coefficient; and a second layer having a third acoustic impedance that is lower than the first and the second acoustic impedances.