# US 10,319,829 B2 · Method and system for in-situ etch and regrowth in gallium nitride based devices

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- Number: US 10,319,829 B2
- Document ID: US10319829B2
- Status: Granted
- Kind: B2
- Application number: 15/681,823
- Filed: 2017-08-21
- Published: 2018-07-05
- Granted: 2019-06-11
- Earliest claimed: 2012-08-10
- Assignees: Nexgen Power Systems, Inc.
- Applicants: Nexgen Power Systems, Inc.
- Inventors: David P. Bour; Thomas R. Prunty; Hui Nie; Madhan M. Raj
- Web page: https://patentgrep.com/patent/US10319829B2

## CPC

- H10D 8/051: {of Schottky diodes}
- H10D 8/041: {of multilayer diodes}
- H10D 8/50: PIN diodes
- H10D 8/60: Schottky-barrier diodes
- H10D 30/01: Manufacture or treatment
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- H10D 62/106: {having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions}
- H10P 14/20: of semiconductor materials
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/271: {characterised by the preparation of substrate for selective deposition}
- H10P 14/272: {using mask materials other than SiO2 or SiN}
- H10P 14/276: {Lateral overgrowth}
- H10P 14/2908: {Nitrides}
- H10P 14/3216: {Nitrides}
- H10P 14/3416: {Nitrides}
- H10P 50/646: {of Group III-V materials}
- H10P 50/695: {characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method of regrowing material includes providing a III-nitride structure including a masking layer and patterning the masking layer to form an etch mask. The method also includes 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 2)

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.

### Claim 5 (depends on 4)

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.

### Claim 6 (depends on 2)

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

### Claim 7 (depends on 6)

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

### Claim 8 (depends on 2)

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

### Claim 9 (depends on 8)

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

### Claim 10 (depends on 1)

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

### Claim 11 (depends on 1)

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.

### Claim 12 (depends on 1)

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

### Claim 13 (depends on 1)

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

### Claim 14 (depends on 1)

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

### Claim 15 (depends on 14)

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

### Claim 16 (depends on 1)

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

### Claim 17 (depends on 16)

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