# US 2019/0355844 A1 · Asymmetrical blocking bidirectional gallium nitride switch

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- Number: US 2019/0355844 A1
- Document ID: US20190355844A1
- Status: Published application
- Kind: A1
- Application number: 16/428,746
- Filed: 2019-05-31
- Published: 2019-11-21
- Earliest claimed: 2016-08-23
- Assignees: Alpha and Omega Semiconductor Incorporated
- Applicants: Alpha and Omega Semiconductor incorporated
- Inventors: David Sheridan
- Web page: https://patentgrep.com/patent/US20190355844A1

## CPC

- H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs}
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- 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 62/824: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 64/111: {Field plates}
- H10D 64/112: {comprising multiple field plate segments}
- H10D 64/512: {Disposition of the gate electrodes, e.g. buried gates}
- H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10D 62/343: {Gate regions of field-effect devices having PN junction gates}
- H10D 64/513: {within recesses in the substrate, e.g. trench gates, groove gates or buried gates}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device includes a hetero-junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The HEMT GaN bidirectional blocking device further includes a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a gate electrode disposed on top of said hetero-junction structure for controlling a current flow between the first and second source/drain electrodes in the 2DEG layer wherein the gate electrode is disposed at a first distance from the first source/drain electrode and a second distance from the second source/drain electrode and the first distance is different from the second distance.

## Claims

### Claim 1

A high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
a hetero-junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer; and
a first source/drain electrode and a second source/drain electrode disposed on two opposite sides of a top surface of the hetero-junction structure;
the first source/drain electrode further includes a first field plate extending laterally toward the second source/drain electrode with a first gate disposed underneath the first field plate; and
the second source/drain electrode further includes a second field plate extending laterally toward the first source/drain electrode with a second gate disposed underneath the first field plate wherein the first field plate is configured to be asymmetrically relative to the second field plate.

### Claim 2 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 wherein:
the first field plate has a length represented by LSD-FP1 and the second field plate has a length represented by LSD-FP2 and wherein LSD-FP1 is different from LSD-FP2.

### Claim 3 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 further comprising:
a sapphire substrate for supporting the hetero-junction structure thereon.

### Claim 4 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 wherein:
the hetero-junction structure comprises a gallium nitride (GaN) as the first semiconductor layer interfacing an AlGaN layer as the second semiconductor layer.

### Claim 5 (depends on 1)

The HEMT semiconductor power device of claim 1 wherein:
the first semiconductor layer is an N-type gallium nitride layer and the second semiconductor layer is an N-type AlGaN layer disposed on top of the gallium nitride layer.

### Claim 6 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 further comprising:
a GaN buffer layer disposed on top of a bottom substrate for supporting the hetero junction structure thereon.

### Claim 7 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 wherein:
the first gate and the second gate comprise a first P-type AlGaN gate and a second P-type AlGaN gate.

### Claim 8 (depends on 1)

The HEMT GaN bidirectional blocking device of claim 1 wherein:
the first source/drain electrode and the second source/drain electrode are composed of a metal selected from a group of metals consists of Ti, Al, Ni and Au.

### Claim 9

A method of forming a high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
forming a hetero-junction structure from a first semiconductor layer interfacing a second semiconductor layer having different band gaps to make a two dimensional gas (2DEG) at the hetero-junction structure;
forming a first source/drain electrode and second source/drain electrode on a top surface and at two opposite ends of the hetero junction structure; and
forming a gate on the top surface of the hetero junction structure with a distance from the first source/drain electrode represented by LGS1/D2 and a distance from the second source/drain electrode represented by LGS2/D1 wherein LGS1/D2 is different from LGS2/D1.

### Claim 10 (depends on 9)

The method of claim 9 wherein:
the process of forming the gate further comprising a step of forming the gate as P-type AlGaN gate.

### Claim 11

A method of forming a high electron mobility transistor (HEMT) gallium nitride (GaN) bidirectional blocking device comprising:
forming a hetero-junction structure from a first semiconductor layer interfacing a second semiconductor layer having different band gaps to make a two dimensional gas (2DEG) at the hetero-junction structure;
forming a first source/drain electrode and second source/drain electrode on a top surface and at two opposite ends of the hetero-junction structure;
forming a first field plate extending from the first source/drain electrode toward the second source/drain electrode and forming a second field plate extending from the second source/drain electrode toward the first source/drain electrode with the second field plate configured asymmetrically from the first field plate;
forming a first gate underneath the first field plate and forming a second gate underneath the second field plate.

### Claim 12 (depends on 9)

The method of claim 9 wherein:
the process of forming the first and the second gates further comprise a step of forming the gates as P-type AlGaN gates.