# US 9,041,065 B2 · Semiconductor heterostructure diodes

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- Number: US 9,041,065 B2
- Document ID: US9041065B2
- Status: Granted
- Kind: B2
- Application number: 13/973,890
- Filed: 2013-08-22
- Published: 2014-02-27
- Granted: 2015-05-26
- Earliest claimed: 2008-12-10
- Assignees: Transphorm Inc.
- Applicants: Transphorm Inc.
- Inventors: Yifeng Wu; Umesh Mishra; Primit Parikh; Rongming Chu; Ilan Ben-Yaacov; Likun Shen
- Web page: https://patentgrep.com/patent/US9041065B2

## CPC

- H10D 62/105: {by having particular doping profiles, shapes or arrangements of PN junctions; by having supplementary regions, e.g. junction termination extension [JTE] (IGFETs having LDD or drain extension regions H10D30/601)}
- H10D 8/60: Schottky-barrier diodes
- H10D 30/471: {High electron mobility transistors [HEMT] or high hole mobility transistors [HHMT]}
- 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 84/811: {Combinations of field-effect devices and one or more diodes, capacitors or resistors}
- H10D 30/47: having two-dimensional [2D] charge carrier gas channels, e.g. nanoribbon FETs or high electron mobility transistors [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 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs}
- H10D 64/513: {within recesses in the substrate, e.g. trench gates, groove gates or buried gates}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.

## Claims

### Claim 1

A diode, comprising:
a semiconductor material comprising a first III-N material layer and a second III-N material layer, wherein a 2DEG channel is in the first III-N material layer because of a compositional difference between the first III-N material layer and the second III-N material layer;
a first insulator layer on the semiconductor material; and
a first terminal and a second terminal, wherein the first terminal comprises an anode that forms a Schottky contact with the semiconductor material and includes an extending portion that extends over the first insulator layer, and a second terminal is a single cathode in ohmic contact with the 2DEG channel.

### Claim 2 (depends on 1)

The diode of claim 1, wherein when the diode is forward biased, current flows from the anode to the cathode predominantly through a Schottky barrier and through the 2DEG channel.

### Claim 3 (depends on 1)

The diode of claim 1, wherein the first III-N material layer includes GaN and the second III-N material layer includes AlaGa1-aN.

### Claim 4 (depends on 1)

The diode of claim 1, wherein the extending portion comprises a field plate.

### Claim 5 (depends on 1)

The diode of claim 1, wherein the extending portion comprises multiple field plates formed as a plurality of steps.

### Claim 6 (depends on 5)

The diode of claim 5, wherein the first insulator layer surrounds the anode and is between the field plate and the second III-N material layer.

### Claim 7 (depends on 1)

An assembly, comprising:
the diode of claim 1; and
a III-N transistor, wherein a terminal of the two terminals of the diode is electrically connected to a terminal of the III-N transistor.

### Claim 8 (depends on 7)

The assembly of claim 7, wherein the terminal of the III-N transistor is a drain, and the anode of the diode is electrically connected to the drain of the III-N transistor.

### Claim 9 (depends on 8)

The assembly of claim 8, wherein the diode and the III-N transistor are on a common substrate.

### Claim 10 (depends on 1)

The diode of claim 1, wherein the second III-N material layer is between the first insulator layer and the first III-N material layer.

### Claim 11 (depends on 10)

The diode of claim 10, wherein the Schottky contact is formed with the second III-N material layer.

### Claim 12 (depends on 10)

The diode of claim 10, wherein the second III-N material layer has a thickness, and the anode extends through an entirety of the thickness of the second III-N material layer to contact the first III-N material layer.

### Claim 13 (depends on 1)

The diode of claim 1, wherein the first and second III-N material layers are N-polar or nitrogen-terminated semi-polar material.

### Claim 14 (depends on 13)

The diode of claim 13, wherein the anode contacts an N-face of the semiconductor material.

### Claim 15 (depends on 1)

The diode of claim 1, wherein the semiconductor material further includes a third III-N material layer and a fourth III-N material layer.

### Claim 16 (depends on 15)

The diode of claim 15, wherein a second 2DEG channel is induced in the third III-N material layer adjacent to the fourth III-N material layer.

### Claim 17 (depends on 1)

The diode of claim 1, further comprising:
a second insulator layer on the first insulator layer; and
a field plate, wherein the field plate extends from the extending portions of the anode and the second insulator layer is between the field plate and the first insulator layer.

### Claim 18 (depends on 1)

The diode of claim 1, further comprising a sidewall insulating material surrounding a lateral sidewall of the anode, wherein a horizontal portion of the anode contacts the first III-N material layer.

### Claim 19 (depends on 1)

The diode of claim 1, further comprising a third III-N material layer between the first III-N material layer and the second III-N material layer.

### Claim 20 (depends on 19)

The diode of claim 19, wherein the third III-N material layer comprises AlN.

### Claim 21

A diode, comprising:
a semiconductor material comprising a first III-N material layer and a second III-N material layer, wherein a 2DEG channel is in the first III-N material layer because of a compositional difference between the first III-N material layer and the second III-N material layer;
a first insulator layer on the semiconductor material;
a second insulator layer on the first insulator layer; and
a first terminal and a second terminal, wherein the first terminal comprises an anode that forms a Schottky contact with the semiconductor material and includes an extending portion that extends over the second insulator layer, and a second terminal is a single cathode in ohmic contact with the 2DEG channel.

### Claim 22 (depends on 21)

The diode of claim 21, wherein the second insulator layer is between the extending portion and the first insulator layer.

### Claim 23 (depends on 21)

The diode of claim 21, wherein the anode contacts the first and second insulator layers.

### Claim 24 (depends on 21)

The diode of claim 21, wherein the second III-N material layer has a thickness, and the anode extends through an entirety of the thickness of the second III-N material layer to contact the first III-N material layer.

### Claim 25

A diode, comprising:
a second III-N material layer on a first III-N material layer;
a 2DEG channel in the first III-N material layer;
a first insulator layer over the second III-N material layer; and
a first terminal and a second terminal, the first terminal comprising an anode that includes a field plate, and a second terminal is a single cathode in ohmic contact with the 2DEG channel; wherein
when the diode is forward biased, current flows from the anode to the cathode predominantly through a Schottky barrier and through the 2DEG channel.

### Claim 26 (depends on 25)

The diode of claim 25, wherein the field plate comprises an extending portion that extends over the first insulator layer.

### Claim 27 (depends on 26)

The diode of claim 26, further comprising a second insulator layer on the first insulator layer.

### Claim 28 (depends on 27)

The diode of claim 27, wherein the second insulator layer is at least partially between the extending portion and the first insulator layer.

### Claim 29 (depends on 25)

The diode of claim 25, further comprising a third III-N material layer, wherein the first, second, and third III-N material layers comprise N-polar or nitrogen-terminated semi-polar material.

### Claim 30 (depends on 25)

The diode of claim 25, wherein the second III-N material layer has a thickness, and the anode extends through an entirety of the thickness of the second III-N material layer.

### Claim 31 (depends on 25)

The diode of claim 25, further comprising a third III-N material layer between the first III-N material layer and the second III-N material layer.

### Claim 32 (depends on 31)

The diode of claim 31, wherein the third III-N material layer comprises AlN.