# US 8,772,835 B2 · Lateral high electron mobility transistor with Schottky junction

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- Number: US 8,772,835 B2
- Document ID: US8772835B2
- Status: Granted
- Kind: B2
- Application number: 13/911,437
- Filed: 2013-06-06
- Published: 2013-10-10
- Granted: 2014-07-08
- Earliest claimed: 2011-04-20
- Assignees: Infineon Technologies Austria AG
- Applicants: Infineon Technologies Austria AG
- Inventors: Markus Zundel; Franz Hirler
- Web page: https://patentgrep.com/patent/US8772835B2

## CPC

- H10D 30/47: having two-dimensional [2D] charge carrier gas channels, e.g. nanoribbon FETs or high electron mobility transistors [HEMT]
- H10D 8/60: Schottky-barrier diodes
- H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 64/411: {for FETs}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A lateral HEMT includes a first semiconductor layer on a second semiconductor layer, a heterojunction at an interface between the first semiconductor layer and the second semiconductor layer, and a rectifying Schottky junction. The rectifying Schottky junction has a first terminal electrically coupled to a source electrode and a second terminal electrically coupled to the second semiconductor layer.

## Claims

### Claim 1

A lateral HEMT, comprising:
a first semiconductor layer on a second semiconductor layer;
a heterojunction at an interface between the first semiconductor layer and the second semiconductor layer; and
a rectifying Schottky junction having a first terminal electrically coupled to a source electrode and a second terminal electrically coupled to the second semiconductor layer.

### Claim 2 (depends on 1)

The lateral HEMT of claim 1, wherein the second semiconductor layer is at least part of the second terminal.

### Claim 3 (depends on 1)

The lateral HEMT of claim 1, wherein the second terminal includes the second semiconductor layer and the first terminal includes a Schottky contact metal of at least one of Ni, Pt, W, Mo, TiSi2, WSi2, and CoSi2 on the second semiconductor layer.

### Claim 4 (depends on 1)

The lateral HEMT of claim 1, wherein a gate electrode of the lateral HEMT and a Schottky contact metal of the Schottky junction are separate parts of the same patterned metal layer.

### Claim 5 (depends on 1)

The lateral HEMT of claim 1, wherein the rectifying Schottky junction includes at least one of p-type GaN and doped polysilicon.

### Claim 6 (depends on 1)

The lateral HEMT of claim 1, wherein a shortest lateral distance between a gate electrode of the lateral HEMT and a drain electrode of the lateral HEMT is larger than the shortest lateral distance between the rectifying Schottky junction and the drain electrode.

### Claim 7 (depends on 1)

The lateral HEMT of claim 1, wherein the first semiconductor layer comprises AlGaN and the second semiconductor layer comprises GaN.

### Claim 8 (depends on 1)

The lateral HEMT of claim 1, wherein the first semiconductor layer comprises GaN and the second semiconductor layer comprises AlGaN.

### Claim 9 (depends on 1)

The lateral HEMT of claim 1, wherein the source electrode, a drain electrode of the lateral HEMT, a gate electrode of the lateral HEMT, and the rectifying junction are generally shaped as stripes extending parallel to each other.

### Claim 10 (depends on 1)

The lateral HEMT of claim 1, further comprising:
a passivation layer above the second semiconductor layer;
a drift region having a lateral width wd; and
at least one field plate arranged at least partially on the passivation layer in a region of the drift region and having a lateral width wf, wherein wf<wd.

### Claim 11 (depends on 10)

The lateral HEMT of claim 10, wherein the at least one field plate is electrically coupled to one of the source electrode, a drain electrode of the lateral HEMT, a gate electrode of the lateral HEMT, and another electrode.

### Claim 12 (depends on 1)

The lateral HEMT of claim 1, further comprising a substrate made of Si, SiC, GaN or Al2O3 and at least one buffer on the substrate.

### Claim 13 (depends on 1)

The lateral HEMT of claim 1, further comprising a metal carrier substrate.

### Claim 14 (depends on 1)

The lateral HEMT of claim 1, further comprising a gate electrode arranged on the second semiconductor layer.

### Claim 15 (depends on 1)

The lateral HEMT of claim 1, further comprising a recessed gate electrode partially extending into the second semiconductor layer.

### Claim 16 (depends on 1)

The lateral HEMT of claim 1, wherein the first terminal of the rectifying Schottky junction is electrically coupled to the source electrode via a plurality of interconnection fingers which form part of a comb-shaped structure including the source electrode and the plurality of interconnection fingers.

### Claim 17

A lateral HEMT, comprising:
a first semiconductor layer on a second semiconductor layer;
a heterojunction at an interface between the first semiconductor layer and the second semiconductor layer;
a Schottky junction including a Schottky contact metal on the second semiconductor layer, the Schottky contact metal being electrically coupled to a source electrode; and
wherein a shortest lateral distance between a gate electrode and a drain electrode is larger than the shortest lateral distance between the Schottky junction and the drain electrode.

### Claim 18 (depends on 17)

The lateral HEMT of claim 17, further comprising:
a passivation layer above the second semiconductor layer;
a drift region having a lateral width wd; and
at least one field plate arranged at least partially on the passivation layer in a region of the drift region and having a lateral width wf, wherein wf<wd.

### Claim 19 (depends on 17)

The lateral HEMT of claim 17, wherein the gate electrode is arranged on the second semiconductor layer.

### Claim 20 (depends on 17)

The lateral HEMT of claim 17, wherein the gate electrode is a recessed gate electrode extending partially into the second semiconductor layer.

### Claim 21 (depends on 17)

The lateral HEMT of claim 17, wherein a first terminal of the rectifying Schottky junction is electrically coupled to the source electrode via a plurality of interconnection fingers which form part of a comb-shaped structure including the source electrode and the plurality of interconnection fingers.

### Claim 22

A lateral HEMT, comprising:
a first semiconductor layer on a second semiconductor layer;
a heterojunction at an interface between the first semiconductor layer and the second semiconductor layer;
a rectifying Schottky junction having a first terminal electrically coupled to a source electrode and a second terminal electrically coupled to the second semiconductor layer;
a passivation layer above the second semiconductor layer;
a drift region having a lateral width wd; and
at least one field plate arranged at least partially on the passivation layer in a region of the drift region and having a lateral width wf, wherein wf<wd.

### Claim 23 (depends on 22)

The lateral HEMT of claim 22, further comprising a gate electrode arranged on the second semiconductor layer.

### Claim 24 (depends on 22)

The lateral HEMT of claim 22, further comprising a recessed gate electrode partially extending into the second semiconductor layer.

### Claim 25 (depends on 22)

The lateral HEMT of claim 22, wherein the first terminal of the rectifying Schottky junction is electrically coupled to the source electrode via a plurality of interconnection fingers which form part of a comb-shaped structure including the source electrode and the plurality of interconnection fingers.