# US 2013/0153968 A1 · Semiconductor Device

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- Number: US 2013/0153968 A1
- Document ID: US20130153968A1
- Status: Published application
- Kind: A1
- Application number: 13/676,903
- Filed: 2012-11-14
- Published: 2013-06-20
- Earliest claimed: 2011-12-19
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.; NXP B. V.
- Inventors: Markus Mueller; Anco Heringa
- Web page: https://patentgrep.com/patent/US20130153968A1

## CPC

- H10D 30/751: {having composition variations in the channel regions}
- H10D 8/60: Schottky-barrier diodes
- H10D 30/47: having two-dimensional [2D] charge carrier gas channels, e.g. nanoribbon FETs or high electron mobility transistors [HEMT]
- H10D 30/4732: {using Group III-V semiconductor material}
- 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 62/117: {Shapes of semiconductor bodies}
- H10D 62/812: {Single quantum well structures}
- 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}
- H10P 14/00: Formation of materials, e.g. in the shape of layers or pillars
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A semiconductor device and a method of making the same. The device includes a semiconductor substrate having an AlGaN layer on a GaN layer. The device also includes first contact and a second contact. The average thickness of the AlGaN layer varies between the first contact and the second contact, for modulating the density of an electron gas in the GaN layer between the first contact and the second contact.

## Claims

### Claim 1

A semiconductor device comprising:
a semiconductor substrate including an AlGaN layer on a GaN layer;
a first contact, and
a second contact,
wherein the average thickness of the AlGaN layer varies between the first contact and the second contact, for modulating the density of an electron gas in the GaN layer between the first contact and the second contact.

### Claim 2 (depends on 1)

The device of claim 1, wherein at least part of an upper surface of the AlGaN layer includes a plurality of recesses for varying an average thickness of the AlGaN layer.

### Claim 3 (depends on 2)

The device of claim 2, wherein a density of the recesses varies for varying the average thickness of the AlGaN layer.

### Claim 4 (depends on 2)

The device of claim 2, wherein the depth of the recesses is between 30% and 100% of the local thickness of the AlGaN layer.

### Claim 5 (depends on 2)

The device of claim 2, wherein the recesses are arranged in a regular array.

### Claim 6 (depends on 2)

The device of claim 2, wherein the recesses comprise grooves.

### Claim 7 (depends on 1)

The device of claim 1, wherein the average thickness T of the AlGaN layer between the first contact and the second contact is in the range 10 nm<T<40 nm.

### Claim 8 (depends on 1)

The device of claim 1 comprising a High Electron Mobility Transistor (HEMT) having a source, a gate and a drain, wherein the first contact comprises said source, and wherein the second contact comprises said drain.

### Claim 9 (depends on 8)

The device of claim 8, wherein the AlGaN layer has a larger average thickness between the source and the gate than between the gate and the drain.

### Claim 10 (depends on 8)

The device of claim 8, wherein the average thickness of the AlGaN layer increases from the gate to the drain.

### Claim 11 (depends on 10)

The device of claim 10, wherein the average thickness of the AlGaN layer increases either linearly or in a series of one or more steps from the gate to the drain.

### Claim 12 (depends on 1)

The device of claim 1, wherein the first contact comprises the anode of a Schottky barrier diode, and wherein the second contact comprises the cathode of said Schottky barrier diode.

### Claim 13 (depends on 12)

The device of claim 12, wherein the average thickness of the AlGaN layer increases from the anode to the cathode.

### Claim 14 (depends on 13)

The device of claim 13, wherein the average thickness of the AlGaN layer increases either linearly or in a series of one or more steps from the anode to the cathode.

### Claim 15

A method of making a semiconductor device, the method comprising:
forming an GaN layer on a substrate;
forming an AlGaN layer on the GaN layer;
forming a first contact and a second contact of the device; and varying the average thickness of the AlGaN layer between the first contact and the second contact, for modulating the density of an electron gas in the GaN layer between the first contact and the second contact.