High output group III nitride light emitting diodes

Patent metadata

Field	Value
Publication number	US-9905731-B2
Application number	US-79636510-A
Country	US
Kind code	B2
Filing date	Jun 8, 2010
Priority date	Sep 22, 2004
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A light emitting diode is disclosed that includes a silicon carbide substrate and a light emitting structure formed from the Group III nitride material system on the substrate. The diode has an area greater than 100,000 square microns and has a radiant flux at 20 milliamps current of at least 29 milliwatts at its dominant wavelength between 390 and 540 nanometers.

First claim

The invention claimed is:

1. A light emitting diode comprising:
a light emitting layer that comprises a Group III nitride material system;
a first ohmic contact on said light emitting layer;
a silver-based layer between said first ohmic contact and said light emitting layer, said silver-based layer including a first face of said silver-based layer adjacent said first ohmic contact, a second face of said silver-based layer adjacent and directly contacting said light emitting layer and a sidewall of said silver-based layer that extends between said first and second faces;
a barrier layer between said first ohmic contact layer and said silver-based layer and directly contacting said first ohmic contact layer, said barrier layer extending on said first face of said silver-based layer and further extending on said sidewall of said silver-based layer to directly contact said light emitting layer;
a transparent conductive substrate on said light emitting layer opposite said silver-based layer; and
a second ohmic contact directly on said transparent conductive substrate opposite said light emitting layer.

2. A light emitting diode according to claim 1 wherein said transparent conductive substrate comprises a silicon carbide single crystal substrate.

3. A light emitting diode according to claim 2 further comprising a buffer layer between said silicon carbide substrate and said light emitting layer, said buffer layer comprising the Group III nitride material system.

4. A light emitting diode according to claim 3 further comprising at least two layers of opposite conductivity type comprising the Group III nitride material system for providing carriers for recombination and light emission under an applied current.

5. A light emitting diode according to claim 4 wherein said light emitting layer includes at least one layer of indium gallium nitride.

6. A light emitting diode according to claim 2 wherein said silicon carbide substrate is n-type and has a polytype selected from the 3C, 4H, 6H, and 15R polytypes of silicon carbide.

7. A light emitting diode according to claim 1 wherein said light emitting layer comprises a doped semiconductor layer, said silver-based layer is directly on said doped semiconductor layer and said barrier layer is directly on said first face of said silver-based layer and completely encloses said sidewall of said silver-based layer.

8. A light emitting diode according to claim 7 wherein said doped semiconductor layer is a p-type semiconductor layer.

9. A light emitting diode according to claim 1 wherein said transparent conductive substrate includes an oblique sidewall.

10. A light emitting diode according to claim 9 ;
wherein said second ohmic contact is directly on a face of said transparent conductive substrate that is opposite said light emitting layer, and
wherein said second ohmic contact extends on only a first portion of said face and exposes a second portion of said face.

Assignees

• Edmond John Adam
• Bergmann Michael J
• Emerson David T
• Haberern Kevin Ward
• Cree Inc

Inventors

• Edmond John Adam
• Bergmann Michael J
• Emerson David T
• Haberern Kevin Ward

Classifications

• H01L33/32 Primary

  Electricity · mapped topic

• H01L33/325

  Electricity · mapped topic

• H01L33/007

  Electricity · mapped topic

• H10H20/8252

  characterised by the dopants · CPC title

• H10H20/01335

  the light-emitting regions comprising nitride materials · CPC title