METHOD AND SYSTEM FOR IN-SITU ETCH AND REGROWTH IN GALLIUM NITRIDE BASED DEVICES

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

providing a III-nitride structure including a masking layer;

patterning the masking layer to form an etch mask;

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

regrowing a III-nitride material in the regrowth region.

2 . The method of claim 1 wherein the III-nitride structure comprises:

a substrate characterized by a first conductivity type;

a first epitaxial layer coupled to the substrate and characterized by the first conductivity type; and

a second epitaxial layer coupled to the first epitaxial layer and characterized by a second conductivity type, wherein the masking layer is coupled to the second epitaxial layer.

3 . The method of claim 2 wherein removing a 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 3 wherein regrowing the III-nitride material is performed in a growth reactor and removing a portion of the second epitaxial layer and a portion of the first epitaxial layer is an in-situ process performed in the growth reactor.

5 . 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.

6 . The method of claim 5 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.

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

8 . The method of claim 7 wherein the III-nitride material comprises GaN.

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

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

11 . The method of claim 1 wherein the masking layer comprises AlN.

12 . The method of claim 11 wherein the AlN is characterized by a thickness less than 4 nm.

13 . A method of fabricating an MPS diode, the method comprising:

providing a III-nitride structure including:

a substrate characterized by a first conductivity type;

a first epitaxial layer coupled to the substrate and characterized by the first conductivity type;

a second epitaxial layer coupled to the first epitaxial layer and characterized by a second conductivity type; and

a masking layer coupled to the second epitaxial layer;

patterning the masking layer to form an etch mask;

placing the III-nitride structure in a growth chamber;

removing a portion of the second epitaxial layer and a portion of the first epitaxial layer to expose a regrowth region;

regrowing a III-nitride material in the regrowth region;

removing the regrown structure 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.

14 . The method of claim 13 wherein the regrowth region extends through the second epitaxial layer to the first epitaxial layer.

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

16 . The method of claim 13 wherein the first epitaxial layer comprises an n-type III-nitride material.

17 . The method of claim 16 wherein the n-type III-nitride material comprises n− GaN.

18 . The method of claim 13 wherein the second epitaxial layer comprises a III-nitride material.

19 . The method of claim 18 wherein the III-nitride material comprises p+GaN.

20 . The method of claim 13 wherein the masking layer comprises AN.