LED with a current confinement structure aligned with a contact

• US 8,410,499 B2
• Filed: 03/25/2008
• Issued: 04/02/2013
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Denbaars, Steven P., Nakamura, Shuji, Batres, Max
• Primary Examiner(s): Huynh, Andy
• Application Number:
  US12/079,486
• Publication Number:
  US 20090121246A1
• Time in Patent Office: 1,834 Days
• Field of Search: 257/79, 257/98, 257/103, 257/E33.068, 257/E33.074
• US Class Current: 257/98
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials

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 confinement structure that is formed within one of the p-type layer of material and the n-type layer of material. The confinement structure is generally aligned with the contact on the top and primary emission surface of the LED and substantially prevents the emission of light from the area of the active region that is coincident with the area of the confinement structure and the top-surface contact. The LED may include a roughened emitting-side surface to further enhance light extraction.

Claims

1. A light emitting diode (LED), comprising:

a base LED structure comprising;

a first doped layer with an associated first contact;

a second doped layer;

an active region between said first and second doped layers;

a current confinement layer positioned adjacent to said second doped layer and axially aligned with said first contact, said current confinement layer including a first face that faces said first contact, a second face that is opposite said first face and at least one sidewall that extends between said first face and said second face;

a second contact on said second doped layer; and

a roughened surface of said light emitting diode;

wherein said second contact extends onto said second face of said current confinement layer that is opposite said first face.

2. The LED of claim 1, wherein said current confinement layer is on said second doped layer.

3. The LED of claim 1, further comprising a submount adjacent to said second doped layer, wherein said current confinement layer and said second contact are on said submount.

4. The LED of claim 1, further comprising a substrate adjacent to said second doped layer wherein said current confinement layer and said second contact are on said substrate.

5. The LED of claim 1, wherein said current confinement layer substantially prevents emission of light from the active region coincident with the area of the active region aligned with said first contact and said current confinement layer.

6. The LED of claim 1, wherein said second contact covers said current confinement layer.

7. The LED of claim 1, wherein said first and second doped layers are oppositely doped.

8. The LED of claim 1, wherein said current confinement layer comprises an insulating material.

9. The LED of claim 1, wherein said current confinement layer comprises a material from the group silicon dioxide (SiO₂), aluminum nitride (A1N) and silicon nitride (SiN).

10. The LED of claim 1, wherein said current confinement layer comprises silicon dioxide (SiO₂).

11. The LED of claim 1, wherein said current confinement layer has a cross-sectional area substantially the same as said first contact.

22. The LED of claim 1 wherein said first doped layer comprises a first layer of semiconductor material and said second doped layer comprises a second layer of semiconductor material.

23. The LED of claim 1 wherein said second contact is in direct contact with said second doped layer.

24. The LED of claim 1 wherein said active region is in adjacent contact with said first doped layer and is in adjacent contact with said second doped layer.

25. The LED of claim 1 wherein said current confinement layer directs current that is flowing toward said active region away from a portion that is substantially aligned with said first contact, and wherein said portion is in said active region.

30. The LED of claim 1, wherein said roughened surface comprises at least a portion of said first doped layer.

31. The LED of claim 1 wherein said roughened surface comprises a layer of at least partially roughened transparent conducting material adjacent said first doped layer.

12. A light emitting diode (LED), comprising:

a first doped layer;

a second doped layer;

an active region between said first and second doped layers;

a first contact on and covering less than all of said first doped layer;

an insulating current confinement layer on and covering less than all of said second doped layer and substantially preventing emission from said active region below said first contact, said insulating current layer including a first face that faces said first contact, a second face that is opposite said first face and at least one sidewall that extends between said first face and said second face;

a second contact on said second doped layer; and

a roughened surface of said light emitting diode;

wherein said second contact extends onto said second face of said current confinement layer that is opposite said first face.

13. The LED of claim 12, wherein said insulating current confinement layer comprises silicon dioxide (Si0₂).

14. The LED of claim 12, further comprising a submount adjacent to said second doped layer, wherein said insulating current confinement layer and said second contact are on said submount.

15. The LED of claim 12, further comprising a substrate adjacent to said second doped layer wherein said insulating current confinement layer and said second contact are on said substrate.

16. The LED of claim 12, wherein said insulating current confinement layer and said first contact are axially aligned.

17. The LED of claim 12, wherein said second contact covers said insulating current confinement layer and substantially all of said second doped layer not covered by said insulating current confinement layer.

18. The LED of claim 12, wherein said second contact covers substantially all of said second doped layer not covered by said insulating current confinement layer.

19. The LED of claim 12, wherein said first and second doped layers are oppositely doped.

20. The LED of claim 12, wherein said insulating current confinement layer comprises a material from the group silicon dioxide (SiO₂), aluminum nitride (AIN) and silicon nitride (SiN).

21. The LED of claim 12, wherein said insulating current confinement layer has a cross-sectional area substantially the same as said first contact.

26. The LED of claim 12 wherein said first doped layer comprises a first layer of semiconductor material and said second doped layer comprises a second layer of semiconductor material.

27. The LED of claim 12 wherein said second contact is in direct contact with said second doped layer.

28. The LED of claim 12 wherein said active region is in adjacent contact with said first doped layer and is in adjacent contact with said second doped layer.

29. The LED of claim 12 wherein said insulating current confinement layer directs current that is flowing toward said active region away from a portion that is substantially aligned with said first contact, and wherein said portion is in said active region.

32. The LED of claim 12, wherein said roughened surface comprises at least a portion of said first doped layer.

33. The LED of claim 12 wherein said roughened surface comprises a layer of at least partially roughened transparent conducting material adjacent said first doped layer.