Patent ID: 8916871

Claim:
A semiconductor device, comprising: a gallium nitride (GaN) substrate having a first surface and a second surface, the second surface being substantially opposite the first surface; at least one device layer coupled to the first surface; a backside metal coupled to the second surface and comprising: an adhesion layer coupled to the second surface of the GaN substrate; a first diffusion barrier coupled to the adhesion layer; and a first protection layer coupled to the first diffusion barrier; and a top metal stack coupled to the at least one device layer and comprising: a contact metal coupled to a surface of the at least one device layer; a second protection layer coupled to the contact metal; a dielectric layer comprising a gap; a second diffusion barrier over the dielectric layer and over the second protection layer in the gap of the dielectric layer; and a pad metal coupled to the second diffusion barrier; wherein the semiconductor device is configured to conduct electricity between the top metal stack and the backside metal.