Patent ID: 8304271

Claim:
A method for making a structure using a substrate, a bulk GaN layer on a first surface of the substrate, wherein the bulk GaN layer has a GaN transistor region and a bulk acoustic wave (BAW) device region, and a source/drain layer over a first surface of the bulk GaN layer in the GaN transistor region, the method comprising: forming a gate electrode over the source/drain layer; forming a first BAW electrode over the first surface of the bulk GaN layer in the BAW device region; forming an opening in a second surface of the substrate, opposite the first surface of the substrate, wherein the opening extends through the substrate and exposes a second surface of the bulk GaN layer, opposite the first surface of the bulk GaN layer; and forming a second BAW electrode within the opening in the second surface of the substrate and in contact with the exposed second surface of the bulk GaN layer, wherein the first surface of the bulk GaN layer is between the source/drain layer and the second surface of the bulk GaN layer, and the first surface of the substrate is between the bulk GaN layer and the second surface of the substrate.