LED with current confinement structure and surface roughening

• US 20090121246A1
• Filed: 03/25/2008
• Published: 05/14/2009
• 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: Nakamura, Shuji, Denbaars, Steven P., Batres, Max
• Granted Patent: US 8,410,499 B2
• Time in Patent Office: Days
• 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 layer and axially aligned with said first contact; and

a contact layer on said second doped layer.

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 contact layer 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 contact layer 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 contact layer 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 (AlN) 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 structure has a cross-sectional area substantially the same as said first contact.

12. A light emitting diode (LED), 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 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 layer and substantially preventing emission from said active region below said first contact; and

a contact layer on said second doped layer.

13. The LED of claim 12, wherein said insulating current confinement layer comprises silicon dioxide (SiO₂).

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

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

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

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

18. The LED of claim 12, wherein said contact layer covers substantially all of said second doped layer not covered by said 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 current confinement layer comprises a material from the group silicon dioxide (SiO₂), aluminum nitride (AlN) and silicon nitride (SiN).

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