Lateral semiconductor Light Emitting Diodes having large area contacts

• US 8,643,039 B2
• Filed: 02/09/2011
• Issued: 02/04/2014
• Est. Priority Date: 11/14/2007
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Donofrio, Matthew, Ibbetson, James, Yao, Zhimin Jamie
• Primary Examiner(s): Luu, Chuong A.
• Application Number:
  US13/023,788
• Publication Number:
  US 20110127568A1
• Time in Patent Office: 1,091 Days
• Field of Search: 257/98, 257/99, 257/88, 257/93, 257/96, 257/95, 257/79, 257/82, 257/83, 257/89
• US Class Current: 257/98
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Light emitting diodes include a diode region having first and second opposing faces that include therein an n-type layer and a p-type layer, an anode contact that ohmically contacts the p-type layer and extends on the first face, and a cathode contact that ohmically contacts the n-type layer and also extends on the first face. The anode and cathode contacts extend on the first face to collectively cover substantially all of the first face. A small gap may be provided between the contacts.

Claims

1. A light emitting diode comprising:

a diode region having first and second opposing faces and including therein an n-type layer and a p-type layer;

a reflective anode contact that ohmically contacts the p-type layer and extends on the first face; and

a reflective cathode contact that ohmically contacts the n-type layer and that also extends on the first face;

wherein the anode and cathode contacts extend on the first face to collectively cover at least about 85% of the first face.

2. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face to collectively cover at least about 90% of the first face.

3. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face to collectively cover at least about 93% of the first face.

4. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face to collectively cover substantially all of the first face.

5. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 75 μ

m therebetween.

6. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 50 μ

m therebetween.

7. A light emitting diode according to claim 1 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 30 μ

m therebetween.

8. A light emitting diode according to claim 1 wherein the cathode contact is larger in area than the anode contact.

9. A light emitting diode according to claim 1 wherein the anode and cathode contacts that both extend on the first face are coplanar.

10. A light emitting diode according to claim 1 further comprising:

a transparent substrate on the second face, the transparent substrate including an inner face adjacent the second face, an outer face remote from the second face that is of smaller area than the inner face, and a sidewall that extends from the outer face to the inner face.

11. A light emitting diode according to claim 10 wherein the sidewall comprises an oblique sidewall that extends at an oblique angle from the outer face towards the inner face.

12. A light emitting diode according to claim 1 in combination with a submount having a submount face and an anode pad and a cathode pad thereon, the light emitting diode being mounted on the submount such that the first face is adjacent the submount face, the outer face is remote from the submount, the anode contact is adjacent the anode pad and the cathode contact is adjacent the cathode pad.

13. A light emitting diode according to claim 12 wherein the anode contact is mounted directly on the anode pad and the cathode contact is mounted directly on the cathode pad.

14. A packaged light emitting diode comprising:

a light emitting diode die comprising;

a diode region having first and second opposing faces and including therein an n-type layer and a p-type layer;

an anode contact that ohmically contacts the p-type layer and extends on the first face;

a cathode contact that ohmically contacts the n-type layer and that also extends on the first face, wherein the anode and cathode contacts extend on the first face to collectively cover at least about 85% of the first face; and

a transparent substrate on the second face, the transparent substrate including an inner face adjacent the second face, an outer face remote from the second face and an oblique sidewall that extends at an oblique angle from the outer face towards the second face; and

a submount having a submount face and an anode pad and a cathode pad thereon, the light emitting diode die being mounted on the submount such that the first face is adjacent the submount face, the outer face is remote from the submount, the anode contact is adjacent the anode pad and the cathode contact is adjacent the cathode pad.

15. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face to collectively cover at least about 90% of the first face.

16. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face to collectively cover at least about 93% of the first face.

17. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face to collectively cover substantially all of the first face.

18. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 75 μ

m therebetween.

19. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 50 μ

m therebetween.

20. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts extend on the first face in closely spaced apart relation to define a gap that is less than about 30 μ

m therebetween.

21. A packaged light emitting diode according to claim 14 wherein the cathode contact is larger in area than the anode contact.

22. A packaged light emitting diode according to claim 14 wherein the anode and cathode contacts that both extend on the first face are coplanar.

23. A packaged light emitting diode according to claim 14 wherein the anode contact is mounted directly on the anode pad and the cathode contact is mounted directly on the cathode pad.