Granted Patent B2

US 9,029,210 · App. 14/302,270 · Granted May 12, 2015

Abstract

Claims (30)

1. A method for fabricating a vertical superjunction device, the method comprising:

providing a III-nitride substrate of a first conductivity type;

forming a first III-nitride epitaxial layer of the first conductivity type coupled to the III-nitride substrate;

forming a second III-nitride epitaxial layer coupled to the first III-nitride epitaxial layer;

forming a third III-nitride epitaxial layer of the first conductivity type coupled to the second III-nitride epitaxial layer;

removing a portion of the third III-nitride epitaxial layer and a portion of the second III-nitride epitaxial layer to expose a sidewall of the second III-nitride epitaxial layer and an exposed surface of the first III-nitride epitaxial layer;

forming a masking material coupled to a surface of a remaining portion of the third III-nitride epitaxial layer;

forming a fourth III-nitride epitaxial layer of the first conductivity type coupled to the sidewall of the second III-nitride epitaxial layer and the exposed surface of the first III-nitride epitaxial layer;

forming a fifth III-nitride epitaxial layer of a second conductivity type coupled to the fourth III-nitride epitaxial layer;

removing at least a portion of the masking material to expose:

the surface of the remaining portion of the third III-nitride epitaxial layer,

a surface of the fourth III-nitride epitaxial layer, and

a surface of the fifth III-nitride epitaxial layer; and

forming one or more insulating structures coupled to the fifth III-nitride epitaxial layer.

2. The method of claim 1 further comprising forming a metal structure coupled to:

at least one of the one or more insulating structures;

the exposed surface of the remaining portion of the third III-nitride epitaxial layer;

the exposed surface of the fourth III-nitride epitaxial layer; and

the exposed surface of the fifth III-nitride epitaxial layer.

3. The method of claim 1 wherein forming at least one of the fourth III-nitride epitaxial layer or the fifth III-nitride epitaxial layer comprises an epitaxial regrowth process.

4. The method of claim 1 further comprising forming a metal structure coupled to the III-nitride substrate, wherein the metal structure forms an ohmic electrical contact with the III-nitride substrate.

5. The method of claim 1 wherein the second III-nitride epitaxial layer is of the second conductivity type.

6. The method of claim 1 wherein the second III-nitride epitaxial layer has intrinsic conductivity.

7. The method of claim 1 further comprising:

forming a first metal structure coupled to the exposed surface of the remaining portion of the third III-nitride epitaxial layer, wherein the first metal structure forms a first ohmic contact with the exposed surface of the remaining portion of the third III-nitride epitaxial layer; and

forming a second metal structure coupled to:

at least one of the one or more insulating structures; and

the fifth III-nitride epitaxial layer, wherein the second metal structure forms a second ohmic contact with the surface of the fifth III-nitride epitaxial layer.

8. The method of claim 1 wherein the fourth III-nitride epitaxial layer and the fifth III-nitride epitaxial layer are substantially charge balanced.

9. The method of claim 1 wherein the first conductivity type is n-type having a dopant including at least one of silicon or oxygen.

Assignments (9)