Granted Patent B2

US 10,319,829 · App. 15/681,823 · Granted Jun 11, 2019

Abstract

Claims (35)

1. A method of regrowing material, the method comprising:

providing a III-nitride structure including a substrate, a first epitaxial layer coupled to the substrate, a second epitaxial layer coupled to the first epitaxial layer, and an epitaxially grown masking layer comprising AlN coupled to the second epitaxial layer;

patterning the epitaxially grown masking layer to form an etch mask;

placing the III-nitride structure in a growth chamber;

removing, using an in-situ etch in the growth chamber, a portion of the III-nitride structure to expose a regrowth region; and

regrowing, in the growth chamber, a regrown III-nitride material in the regrowth region and over at least a portion of the etch mask.

2. The method of claim 1 wherein:

the substrate is characterized by a first conductivity type;

the first epitaxial layer is characterized by the first conductivity type; and

the second epitaxial layer is characterized by a second conductivity type opposite to the first conductivity type.

3. The method of claim 2 wherein removing, using the in-situ etch, the portion of the III-nitride structure comprises removing a portion of the second epitaxial layer and a portion of the first epitaxial layer, wherein the regrowth region is disposed in the first epitaxial layer.

4. The method of claim 2 further comprising

removing a portion of the regrown III-nitride material to expose the second epitaxial layer;

forming a first electrical contact to portions of the first epitaxial layer and portions of the second epitaxial layer; and

forming a second electrical contact to the substrate.

5. The method of claim 4 wherein the first electrical contact comprises:

a Schottky contact to the portions of the first epitaxial layer; and

an ohmic contact to the portions of the second epitaxial layer.

6. The method of claim 2 wherein the first epitaxial layer comprises an n-doped III-nitride material.

7. The method of claim 6 wherein the n-doped III-nitride material comprises GaN.

8. The method of claim 2 wherein the second epitaxial layer comprises a III-nitride material.

9. The method of claim 8 wherein the III-nitride material comprises GaN.

10. The method of claim 1 wherein the epitaxially grown masking layer comprising AlN is characterized by a thickness less than 4 nm.

11. The method of claim 1 , further comprising:

removing the regrown III-nitride material from the growth chamber;

removing a portion of the regrown III-nitride material to expose the second epitaxial layer;

forming a Schottky contact to the regrown III-nitride material;

forming an ohmic contact to portions of the second epitaxial layer; and

forming a second ohmic contact to the substrate.

12. The method of claim 1 wherein the regrowth region extends through the second epitaxial layer to the first epitaxial layer.

13. The method of claim 1 wherein the growth chamber comprises an MOCVD reactor.

14. The method of claim 1 wherein the first epitaxial layer comprises an n-type III-nitride material.

15. The method of claim 14 wherein the n-type III-nitride material comprises n− GaN.

16. The method of claim 1 wherein the second epitaxial layer comprises a III-nitride material.

17. The method of claim 16 wherein the III-nitride material comprises p+ GaN.

Assignments (6)