Method of fabricating vertical structure LEDs

• US 7,569,865 B2
• Filed: 12/03/2004
• Issued: 08/04/2009
• Est. Priority Date: 04/09/2002
• Status: Expired due to Term

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Jong-Lam, Jeong, In-kwon, Yoo, Myung Cheol
• Primary Examiner(s): Mandala; Victor A
• Application Number:
  US11/002,413
• Publication Number:
  US 20050098792A1
• Time in Patent Office: 1,705 Days
• Field of Search: 257/99, 257/79, 257/103, 257/E33.025
• US Class Current: 257/99
• CPC Class Codes: H01C 7/006 Thin film resistors
• CPC Class Codes: H01C 7/008 Thermistors H01C7/02 - H01C7/06 take precedence
• CPC Class Codes: H01L 27/0802 Resistors only
• CPC Class Codes: H01L 28/20 Resistors
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/36 characterised by the electrodes
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/40 Materials therefor
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• 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
• CPC Class Codes: Y10S 438/958 Passivation layer
• CPC Class Codes: Y10S 438/977 Thinning or removal of substrate

Abstract

A method of fabricating semiconductor devices, such as GaN LEDs, on insulating substrates, such as sapphire. Semiconductor layers are produced on the insulating substrate using normal semiconductor processing techniques. Trenches that define the boundaries of the individual devices are then formed through the semiconductor layers and into the insulating substrate, beneficially by using inductive coupled plasma reactive ion etching. The trenches are then filled with an easily removed layer. A metal support structure is then formed on the semiconductor layers (such as by plating or by deposition) and the insulating substrate is removed. Electrical contacts, a passivation layer, and metallic pads are then added to the individual devices, and the individual devices are then diced out.

Claims

1. A light-emitting device, comprising:

a conductive support structure;

a first-type GaN based layer over the conductive support structure;

a first electrode disposed between the conductive support structure and the first-type GaN based layer such that the first-type GaN based layer is over the first electrode;

a second-type GaN based layer over the first-type GaN based layer;

a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer;

a passivation layer over surfaces of the first-type GaN based layer, of the light emitting layer, of the second-type GaN based layer, and of the first electrode; and

a second electrode over the second-type GaN based layer,

wherein the first electrode and the second electrode are respectively located at opposite sides of the light-emitting layer, and wherein the passivation layer is located over at least an upper portion of the conductive support structure.

2. The light-emitting device according to claim 1, further including a metallic pad over the second electrode.

3. The light-emitting device according to claim 1, wherein the passivation layer is positioned such that the passivation layer is located over at least a part of the second electrode.

4. The light-emitting device according to claim 1, wherein the passivation layer comprises material including at least one of Si, O, N, and photo-resist.

5. The light-emitting device according to claim 1, wherein the second-type GaN based layer is doped with silicon.

6. The light-emitting device according to claim 1, wherein the conductive support structure includes a metal selected from a group including Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, Ti, and Al.

7. The light-emitting device according to claim 1, wherein the conductive support structure includes titanium nitride.

8. The light-emitting device according to claim 1, wherein the passivation layer is disposed higher than the second electrode.

9. The light-emitting device according to claim 1, wherein the passivation layer extends to at least an upper surface of the conductive support structure.

10. A light-emitting device, comprising:

a support structure;

a first-type GaN based layer over the support structure;

a first electrode disposed between the support structure and the first-type GaN based layer such that the first-type GaN based layer is over the first electrode; and

a second-type GaN based layer over the first-type GaN based layer, wherein the second-type GaN based layer comprises undoped GaN and doped GaN, and wherein the second-type GaN based layer further comprises a surface of pure doped GaN;

a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer;

a passivation layer over exposed portions of the first-type GaN based layer, of the light emitting layer, of the second-type GaN based layer; and

a second electrode over the surface of pure doped GaN of the second-type GaN based layer, and the first electrode and the second electrode are respectively located at opposite sides of the light-emitting layer.

11. The light-emitting device according to claim 10, wherein the first-type GaN based layer is a p-GaN based layer and the second-type GaN based layer is an n-GaN based layer.

12. The light-emitting device according to claim 10, wherein the first-type GaN based layer is an n-GaN based layer and the second-type GaN based layer is a p-GaN based layer.

13. The light-emitting device according to claim 10, further comprising a metallic pad over the second electrode.

14. The light-emitting device according to claim 10, wherein the passivation layer is disposed higher than the second electrode.

15. The light-emitting device according to claim 10, wherein the passivation layer comprises material including at least one of Si, O, and N.

16. The light-emitting device according to claim 10, wherein the support structure includes metallic material.

17. The light-emitting device according to claim 10, wherein the support structure includes a metal selected from a group including Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W and Al.

18. The light-emitting device according to claim 10, wherein the passivation layer is located over exposed portions of at least one of the undoped GaN and the first electrode.

19. A vertical light-emitting device, comprising:

a support structure including a metal layer;

a first-type GaN based layer over the support structure;

a first electrode disposed between the support structure and the first-type GaN based layer such that first-type GaN based layer is over the first electrode;

a second-type GaN based layer thicker than the first-type GaN based layer over the first-type GaN based layer;

a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer;

a passivation layer covering at least two side portions of the first-type GaN based layer, the light emitting layer, and the second-type GaN based layer; and

a second electrode over the second-type GaN based layer, and the first electrode and the second electrode are respectively located at opposite sides of the light-emitting layer, wherein the passivation layer is located over at least an upper level of the support structure.

20. The vertical light-emitting device according to claim 19 wherein the first-type GaN based layer is a p-GaN based layer and the second-type GaN based layer is an n-GaN based layer.

21. The vertical light-emitting device according to claim 19, wherein the first-type GaN based layer is an n-GaN based layer and the second-type GaN based layer is a p-GaN based layer.

22. The vertical light-emitting device according to claim 19, wherein the passivation layer surrounds at least two side portions of the first-type GaN based layer, the light emitting layer, and the second-type GaN based layer.

23. The vertical light-emitting device according to claim 19, wherein the passivation layer comprises material including at least one of Si, O, N, and photo-resist.

24. The vertical light-emitting device according to claim 19, wherein the support structure includes metallic material.

25. The vertical light-emitting device according to claim 19, wherein the support structure includes a metal selected from a group including Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, Ti, and Al.

26. The vertical light-emitting device according to claim 19, wherein the passivation layer extends to at least an upper level of the support structure.

27. The vertical light-emitting device according to claim 19, wherein the passivation layer is over a surface of the first electrode.

28. A vertical light-emitting device, comprising:

a support layer;

a p-type GaN based layer over the support layer;

a first electrode disposed between the support layer and the p-type GaN based layer such that p-type GaN based layer is disposed over the first electrode;

a n-type GaN based layer over the p-type GaN based layer;

a light-emitting layer disposed between the p-type GaN based layer and the n-type GaN based layer;

a passivation layer surrounding at least two side portions of the p-type GaN based layer, the light emitting layer, and the n-type GaN based layer;

a second electrode over the n-type GaN based layer, wherein the second electrode is disposed in the area surrounded by the passivation layer, wherein an area of the passivation layer covering the n-type GaN based layer is larger than an area of the passivation layer covering the p-type GaN based layer.

29. The vertical light-emitting device according to claim 28, wherein the passivation layer covers at least two side portions of the first electrode.

30. The vertical light-emitting device according to claim 28, the passivation layer is higher than an upper surface of the n-type GaN based layer.

31. A vertical light-emitting device, comprising:

a support structure;

a first-type GaN based layer over the support structure;

a first electrode disposed between the support structure and the first-type GaN based layer such that first-type GaN based layer is over the first electrode;

a second-type GaN based layer over the first-type GaN based layer;

a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer;

a second electrode over the second-type GaN based layer;

a passivation layer disposed partially between the support structure and the first-type GaN based layer, wherein at least a portion of the passivation layer is located over at least an upper portion of the support structure.

32. The vertical light-emitting device according to claim 31, wherein the passivation layer is over a surface of the first electrode.

33. The vertical light-emitting device according to claim 31, wherein the first electrode comprises at least two layers including a first layer and a second layer, wherein the first layer and the second layer include different materials.

34. The vertical light-emitting device according to claim 33, wherein at least one of the first layer and the second layer includes a transparent conductive material.

35. A vertical light-emitting device, comprising:

a support structure;

a first-type GaN based layer over the support structure;

a first electrode disposed between the support structure and the first-type GaN based layer such that first-type GaN based layer is over the first electrode;

a second-type GaN based layer over the first-type GaN based layer;

a light-emitting layer disposed between the first-type GaN based layer and the second-type GaN based layer;

a plurality of passivation layers over surfaces of the first-type GaN based layer, of the light emitting layer, and of the second-type GaN based layer,

a second electrode over the second-type GaN based layer, wherein the first electrode and the second electrode are respectively located at opposite sides of the light-emitting layer, and wherein at least a portion of the passivation layer is located over at least an upper surface of the support structure.

36. The vertical light-emitting device according to claim 35, wherein the plurality of passivation layers are over a surface of the first electrode.