# US 8,785,975 B2 · GAN vertical superjunction device structures and fabrication methods

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- Number: US 8,785,975 B2
- Document ID: US8785975B2
- Status: Granted
- Kind: B2
- Application number: 13/529,822
- Filed: 2012-06-21
- Published: 2013-12-26
- Granted: 2014-07-22
- Earliest claimed: 2012-06-21
- Assignees: Avogy, Inc.
- Applicants: Hui Nie; Andrew P. Edwards; Donald R. Disney; Isik C. Kizilyalli
- Inventors: Hui Nie; Andrew P. Edwards; Donald R. Disney; Isik C. Kizilyalli
- Web page: https://patentgrep.com/patent/US8785975B2

## CPC

- H10P 14/3416: {Nitrides}
- H10D 30/475: {having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs}
- H10D 84/01: Manufacture or treatment
- H10D 84/05: using Group III-V technology
- H10P 14/38: {characterised by treatments done after the formation of the materials}
- H10D 62/117: {Shapes of semiconductor bodies}
- Y10S 438/978: forming tapered edges on substrate or adjacent layers
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A semiconductor device includes a III-nitride substrate of a first conductivity type, a first III-nitride epitaxial layer of the first conductivity type coupled to the III-nitride substrate, and a first III-nitride epitaxial structure coupled to a first portion of a surface of the first III-nitride epitaxial layer. The first III-nitride epitaxial structure has a sidewall. The semiconductor device further includes a second III-nitride epitaxial structure of the first conductivity type coupled to the first III-nitride epitaxial structure, a second III-nitride epitaxial layer of the first conductivity type coupled to the sidewall of the second III-nitride epitaxial layer and a second portion of the surface of the first III-nitride epitaxial layer, and a third III-nitride epitaxial layer of a second conductivity type coupled to the second III-nitride epitaxial layer. The semiconductor device also includes one or more dielectric structures coupled to a surface of the third III-nitride epitaxial layer.

## Claims

### Claim 1

A semiconductor device comprising:
a III-nitride substrate of a first conductivity type;
a first III-nitride epitaxial layer of the first conductivity type coupled to the III-nitride substrate;
a first III-nitride epitaxial structure coupled to a first portion of a surface of the first III-nitride epitaxial layer, the first III-nitride epitaxial structure having a sidewall;
a second III-nitride epitaxial structure of the first conductivity type coupled to the first III-nitride epitaxial structure;
a second III-nitride epitaxial layer of the first conductivity type coupled to the sidewall of the second III-nitride epitaxial structure and a second portion of the surface of the first III-nitride epitaxial layer;
a third III-nitride epitaxial layer of a second conductivity type coupled to the second III-nitride epitaxial layer;
one or more dielectric structures having at least a first surface coupled to a surface of the third III-nitride epitaxial layer; and
a first metal structure coupled to the third III-nitride epitaxial layer and a second surface of the one or more dielectric structures opposite the first surface.

### Claim 2 (depends on 1)

The semiconductor device of claim 1 further comprising a metal structure coupled to:
at least one of the one or more dielectric structures;
the second III-nitride epitaxial structure;
the second III-nitride epitaxial layer; and
the third III-nitride epitaxial layer.

### Claim 3 (depends on 1)

The semiconductor device of claim 1 further comprising a second metal structure forming an ohmic electrical contact with the III-nitride substrate.

### Claim 4 (depends on 1)

The semiconductor device of claim 1 wherein the first III-nitride epitaxial structure is of the second conductivity type.

### Claim 5 (depends on 1)

The semiconductor device of claim 1 wherein the first III-nitride epitaxial structure has intrinsic conductivity.

### Claim 6 (depends on 1)

The semiconductor device of claim 1 wherein the first metal structure forms a first ohmic contact with the surface of the third III-nitride epitaxial layer further comprising:
a second metal structure forming a second ohmic contact with the second III-nitride epitaxial structure.

### Claim 7 (depends on 1)

The semiconductor device of claim 1 wherein the second III-nitride epitaxial layer and the third III-nitride epitaxial layer are substantially charge balanced.

### Claim 8

A vertical superjunction gate field-effect transistor structure comprising:
a substrate comprising a III-nitride material of a first conductivity type;
a current blocking region coupled to the substrate and comprising a III-nitride epitaxial material;
a source region coupled to the current blocking region and comprising a III-nitride epitaxial material of the first conductivity type;
a first metal contact structure coupled to the source region;
a substantially charge-balanced region adjacent to the current blocking region, the substantially charge-balanced region comprising:
a layer of III-nitride epitaxial material of the first conductivity type, and
a layer of III-nitride epitaxial material of a second conductivity type;
wherein the substantially charge-balanced region is configured to conduct a current when the transistor structure is under forward-bias conditions;
one or more dielectric structures having at least a first surface coupled to at least a portion of the substantially charge-balanced region; and
a second metal contact structure coupled to:
a second surface of the one or more dielectric structures opposite the first surface, and
at least a portion of the substantially charge-balanced region.

### Claim 9 (depends on 8)

The transistor structure of claim 8 further comprising a metal-oxide-semiconductor field-effect transistor electrically coupled in series with the transistor structure.