# US 8,772,792 B2 · LED with surface roughening

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- Number: US 8,772,792 B2
- Document ID: US8772792B2
- Status: Granted
- Kind: B2
- Application number: 13/974,505
- Filed: 2013-08-23
- Published: 2013-12-26
- Granted: 2014-07-08
- Earliest claimed: 2005-01-24
- Assignees: Cree, Inc.
- Applicants: Cree, Inc.
- Inventors: Steven P. DenBaars; Shuji Nakamura; Max Batres
- Web page: https://patentgrep.com/patent/US8772792B2

## CPC

- H10H 20/833: Transparent materials
- H10H 20/8162: {Current-blocking structures}
- H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers
- H10H 20/835: {Reflective materials}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

An LED having a p-type layer of material with an associated p-contact, an n-type layer of material with an associated n-contact and an active region between the p-type layer and the n-type layer, includes a roughened emitting-side surface to further enhance light extraction.

## Claims

### Claim 1

A light emitting diode (LED) comprising:
a first layer of first conductivity type having an associated first contact;
a second layer of second conductivity type having an associated second contact;
an active region between the first and second layers; and
a layer comprising transparent conductive material between the first layer and the first contact and extending on the first layer beyond the first contact, the layer comprising transparent material having a first face adjacent the first layer and a second face remote from the first layer, the second face being smooth beneath the first contact and at least a portion of the second face being rough beyond the first contact.

### Claim 2 (depends on 1)

The LED of claim 1 wherein the transparent conductive material comprises a transparent conductive oxide.

### Claim 3 (depends on 2)

The LED of claim 2 wherein the transparent conductive oxide comprises ZnO, In2O3 or Indium Tin Oxide (ITO).

### Claim 4 (depends on 1)

The LED of claim 1 wherein the second contact comprises reflective material.

### Claim 5 (depends on 1)

The LED of claim 1 wherein the first conductivity type is p-type and the second conductivity type is n-type.

### Claim 6 (depends on 5)

The LED of claim 5 further comprising a semiconductor substrate on the second layer remote from the active region.

### Claim 7 (depends on 1)

The LED of claim 1 wherein the first conductivity type is n-type and the second conductivity type is p-type.

### Claim 8 (depends on 7)

The LED of claim 7 further comprising a submount on the second layer remote from the active region.

### Claim 9 (depends on 1)

The LED of claim 1 wherein the first layer, second layer and active region comprise Group III nitride materials.

### Claim 10 (depends on 1)

The LED of claim 1 wherein the first and second contacts are laterally arranged on a same side of the LED.

### Claim 11

A light emitting diode (LED) comprising:
a first layer of first conductivity type having an associated first contact;
a second layer of second conductivity type having an associated second contact;
an active region between the first and second layers; and
a layer comprising transparent conductive material between the first layer and the first contact and extending on the first layer beyond the first contact, the layer comprising transparent material having a first face adjacent the first layer and a second face remote from the first layer, the first contact having a first face adjacent the first layer and a second face remote from the first layer, wherein the second face of the layer comprising transparent conductive material extends further away from the first layer than the first face of the first contact.

### Claim 12 (depends on 11)

The LED of claim 11 wherein the transparent conductive material comprises a transparent conductive oxide.

### Claim 13 (depends on 12)

The LED of claim 12 wherein the transparent conductive oxide comprises ZnO, In2O3 or Indium Tin Oxide (ITO).

### Claim 14 (depends on 11)

The LED of claim 11 wherein the second contact comprises reflective material.

### Claim 15 (depends on 11)

The LED of claim 11 wherein the first conductivity type is p-type and the second conductivity type is n-type.

### Claim 16 (depends on 15)

The LED of claim 15 further comprising a semiconductor substrate on the second layer remote from the active region.

### Claim 17 (depends on 11)

The LED of claim 11 wherein the first conductivity type is n-type and the second conductivity type is p-type.

### Claim 18 (depends on 17)

The LED of claim 17 further comprising a submount on the second layer remote from the active region.

### Claim 19 (depends on 11)

The LED of claim 11 wherein the first layer, second layer and active region comprise Group III nitride materials.

### Claim 20 (depends on 11)

The LED of claim 11 wherein the first and second contacts are laterally arranged on a same side of the LED.

### Claim 21 (depends on 11)

The LED of claim 11 wherein the second face of the layer comprising transparent conductive material is smooth beneath the first contact and at least a portion of the second face of the layer comprising transparent conductive material is rough beyond the first contact.