High efficiency group III nitride LED with lenticular surface

• US 8,878,209 B2
• Filed: 02/19/2014
• Issued: 11/04/2014
• Est. Priority Date: 09/22/2004
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Edmond, John Adam, Slater, David B. Jr., Bharathan, Jayesh, Donofrio, Matthew
• Primary Examiner(s): Lee, Eugene
• Application Number:
  US14/183,955
• Publication Number:
  US 20140167089A1
• Time in Patent Office: 258 Days
• Field of Search: 257/94, 257/95, 257/98, 257/99
• US Class Current: 257/94
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

A high efficiency Group III nitride light emitting diode is disclosed. The diode includes a Group III nitride-based light emitting region including a plurality of Group III nitride-based layers. A lenticular surface directly contacts one of the Group III nitride-based layers of the light emitting region. The lenticular surface includes a transparent material that is different from the Group III nitride-based layer of the light emitting region that the lenticular surface directly contacts.

Claims

1. A high efficiency Group III nitride light emitting diode comprising:

a Group III nitride-based light emitting region comprising a plurality of Group III nitride-based layers; and

a lenticular surface that directly contacts one of said Group III nitride-based layers of said light emitting region, the lenticular surface comprising transparent material that is different from the one of said Group III nitride-based layers of said light emitting region that the lenticular surface directly contacts.

2. A light emitting diode according to claim 1, wherein said lenticular surface directly contacts, but does not extend into, said one of said Group III nitride-based layers of said light emitting region.

3. A light emitting diode according to claim 1 wherein said lenticular surface extends into said one of said Group III nitride-based layers of said light emitting region.

4. A light emitting diode of claim 1, wherein said lenticular surface contains silicon carbide.

5. A light emitting diode according to claim 1 wherein said lenticular surface comprises single crystal silicon carbide.

6. A light emitting diode according to claim 1 further comprising an ohmic contact to said light emitting region.

7. A light emitting diode according to claim 1 further comprising a phosphor-containing structure adjacent said lenticular surface and configured to convert emissions from said light emitting region into frequencies that will produce white light.

8. A light emitting diode according to claim 1 wherein said lenticular surface comprises a plurality of cones.

9. A light emitting diode according to claim 1 wherein said lenticular surface comprises a plurality of pyramids.

10. A light emitting diode according to claim 1 wherein said plurality of Group III nitride-based layers comprises at least one p-type layer of Group III nitride and at least one n-type layer of Group III nitride for current injection and recombination of carriers in said light emitting region.

11. A light emitting diode according to claim 1 wherein said light emitting region comprises a mesa structure.

12. A light emitting diode according to claim 11 comprising a passivation layer on at least portions of said mesa.

13. A light emitting diode according to claim 11 comprising a passivation layer on at least portions of said mesa and on at least portions of said lenticular surface.