Patent attributes
A temperature-compensated BAW resonator is disclosed. In an embodiment, the BAW includes a substrate and a layer stack disposed thereon, the layer stack including a bottom electrode layer, a top electrode layer, a piezoelectric layer arranged between the bottom and top electrode layers and an acoustic mirror arranged between the bottom electrode layer and the substrate, wherein the acoustic mirror comprises at least two mirror layers, wherein the acoustic mirror comprises high impedance and low impedance layers arranged in an alternating sequence. The layer stack further includes a compensation layer including a material having a positive temperature coefficient of viscoelastic properties, wherein the compensation layer is arranged between the acoustic mirror and the bottom electrode layer, wherein the mirror layers together form a Bragg mirror.
