Granted Patent B2

US 8,916,871 · App. 13/611,467 · Granted Dec 23, 2014

Abstract

Claims (41)

1. 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.

2. The semiconductor device of claim 1 wherein the contact metal forms an Ohmic contact with at least a portion of the at least one device layer.

3. The semiconductor device of claim 1 wherein the contact metal forms a Schottky contact with at least a portion of the at least one device layer.

4. The semiconductor device of claim 1 wherein the contact metal comprises at least one of:

platinum,

palladium,

titanium,

titanium nitride,

aluminum,

silver, or

nickel.

5. The semiconductor device of claim 1 wherein either or both of the first protection layer or the second protection layer comprises gold.

6. The semiconductor device of claim 1 wherein the pad metal has a thickness of at least 2 microns and comprises at least one of:

aluminum, or

copper.

7. The semiconductor device of claim 1 wherein either or both of the first diffusion barrier or the second diffusion layer comprises at least one of:

nickel,

chromium,

molybdenum,

tungsten, or

titanium.

8. The semiconductor device of claim 1 further comprising an aluminum bond wire electrically connecting the pad metal to a package.

9. The semiconductor device of claim 1 further comprising a solder mechanically and electrically connecting the backside metal to a lead frame.

10. The semiconductor device of claim 1 wherein the adhesion layer comprises at least one of:

Ti,

Al,

Pd, and

Cr.

Assignments (12)