Light emitting diodes and fabrication methods thereof

• US 7,829,909 B2
• Filed: 05/30/2007
• Issued: 11/09/2010
• Est. Priority Date: 11/15/2005
• Status: Expired due to Fees

• Current Assignee: Verticle, Inc.
• Original Assignee: Verticle, Inc.
• Inventors: Yoo, Myung Cheol
• Primary Examiner(s): Nguyen; Dao H
• Assistant Examiner(s): NGUYEN, TRAM HOANG
• Application Number:
  US11/755,650
• Publication Number:
  US 20070221944A1
• Time in Patent Office: 1,259 Days
• Field of Search: 257/79, 257/82, 257/93, 257/94, 257/98, 257/99, 257/100, 257/103, 257/125, 257/144, 257/152, 257/164, 257/183, 257/189, 257/190, 257/198, 257/432, 257/433, 257/434, 257/435, 257/436, 257/437, 257/514, 257/749, 257/E33.056, 257/E33.057, 257/E33.058, 257/E33.059, 257/E25.032, 438/20, 438/28, 438/342, 438/343, 438/344, 438/345, 438/346
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A light emitting diode (LED) may be disclosed. The LED may include a light-emitting side. The LED may also include a first electrode disposed on the light-emitting side. The LED may also include a second electrode. The LED may also include a semiconductor element disposed between the first electrode and the second electrode. The LED may also include a metal support element disposed between the semiconductor element and the second electrode. The metal support element may be configured to provide structural support for the LED.

Claims

1. A light emitting diode (LED) comprising:

a light-emitting side;

a first electrode disposed on the light-emitting side;

a second electrode;

a semiconductor element disposed between the first electrode and the second electrode; and

a metal support element disposed between the semiconductor element and the second electrode, the metal support element configured to provide structural support for the LED;

one or more adhesion layers disposed between the semiconductor element and the metal support element and configured to form part of an electrical path between the semiconductor element and the metal support element, wherein the one or more adhesion layers include a first adhesion layer, the first adhesion layer being in contact with at least one of a metal contact and a metal intermediate layer, the metal contact being in contact with the semiconductor element, the metal intermediate layer being in contact with the metal support layer.

2. The LED of claim 1 wherein a length of the light-emitting side at least three times a width of the light-emitting side.

3. The LED of claim 1 wherein a length of the light-emitting side is at least seven times a width of the light-emitting side.

4. The LED of claim 1 further comprising a first extension connected to the first electrode, the first extension is disposed on the light-emitting side, running over the light-emitting side and configured for spreading current on the light-emitting side.

5. The LED of claim 4 wherein a length of the first extension is at least three times a width of the light-emitting side.

6. The LED of claim 4 wherein the first electrode further includes a second extension, the first extension and the second extension having a same length.

7. The LED of claim 4 wherein the first electrode further includes a second extension, the first extension and the second extension having a same width but different lengths.

8. The LED of claim 4 wherein the first extension includes a first section, a second section, and a third section between the first section and the second section, the first section may be disposed closer to a first edge of the light-emitting side than the second section, and the second section may be disposed closer to a second edge of the light-emitting side than the first section.

9. The LED of claim 8 wherein the first section may be parallel to the first edge of the light-emitting side, and the second section may be parallel to the second edge of the light-emitting side.

10. The LED of claim 4 further comprising a third electrode disposed on the light-emitting side, the first electrode and the third electrode having a same polarity.

11. The LED of claim 10 wherein the third electrode includes an extended portion configured to facilitate current spreading on the light-emitting side.

12. The LED of claim 11 wherein the extended portion may be aligned with the first extension.

13. The LED of claim 11 wherein the first extension may be disposed closer to a first edge of the light-emitting side than the extended portion.

14. The LED of claim 1 wherein the semiconductor element includes a p-type portion and an n-type portion, the p-type portion is disposed closer to the metal support element than the n-type portion, and the n-type portion is disposed closer to the light-emitting side than the p-type portion.

15. The LED of claim 1 wherein the semiconductor element is made of one or more materials including at least one of GaN, AlGaN, AlGaAs, AlGaP, AlGalnP, GaAsP, GaP, and InGaN.

16. The LED of claim 1 wherein the semiconductor element is made of one or more materials including GaN.

17. The LED of claim 1 wherein the semiconductor element includes a textured surface configured to optimize photon escape angles.

18. The LED of claim 17 wherein the textured surface is a surface of an n-type portion of the semiconductor element.

19. The LED of claim 1 wherein the first electrode is a cathode and the second electrode may be an anode.

20. The LED of claim 1 wherein the second electrode is electrically coupled with the metal support element and configured to protect the metal support element from oxidation.

21. The LED of claim 1 wherein the metal support element includes a first metal element and a second metal element, the first metal element is disposed closer to the semiconductor element than the second metal element, and the first element is configured to reduce stress buildup in the LED.

22. The LED of claim 1 wherein the metal support element is made of one or more materials including Cu.

23. The LED of claim 1 further comprising a current blocking element disposed between the first electrode and the semiconductor element, disposed on an n-type portion of the semiconductor, and configured to expel electrons, wherein the first electrode is a cathode.

24. The LED of claim 1 further comprising an n-type current spreading element disposed between the first electrode and the semiconductor element.

25. The LED of claim 24 wherein the n-type current spreading element is an n-type ITO element in contact with a current blocking element and in contact with a textured surface of an n-type portion of the semiconductor element.

26. The LED of claim 1 further comprising a metal intermediate layer disposed between the semiconductor element and the metal support element, the metal intermediate layer being in contact with the metal support element, the metal intermediate layer and the metal support element being made of different materials.

27. The LED of claim 1 wherein the one or more adhesion layers are made of one or more of Ni, Au, and Pd.

28. The LED of claim 1 wherein the first adhesion layer is made of one or more materials including Ni.

29. The LED of claim 1 wherein the one or more adhesion layers further include a second adhesion layer in contact with the metal intermediate layer and a third adhesion layer disposed between the first adhesion layer and the second adhesion layer.

30. The LED of claim 1 wherein the metal contact is a p-contact.

31. The LED of claim 1 wherein a thickness of the metal support element is greater than 50 um.