Method of fabricating vertical structure LEDs

• US 7,576,368 B2
• Filed: 09/05/2007
• Issued: 08/18/2009
• 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: Yoo, Myung Cheol, Jeong, In-Kwon, Lee, Jong-Lam
• Primary Examiner(s): Mandala; Victor A
• Application Number:
  US11/896,772
• Publication Number:
  US 20080001166A1
• Time in Patent Office: 713 Days
• Field of Search: 257/79, 257/99, 257/103, 257/E33.023, 257/E33.025, 257/E33.075
• 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 vertical light emitting device, comprising:

a support layer;

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

a first electrode disposed between the support layer 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, 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 doped GaN;

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

an undoped GaN based layer over the second-type GaN based layer; and

a second electrode over the second-type GaN based layer or the undoped GaN based layer, wherein the first electrode and the second electrode are respectively located at opposite sides of the light emitting layer.

2. The vertical light emitting device of claim 1, 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.

3. The vertical light emitting device of claim 1, further comprising a cover layer over at least one exposed portion of the first-type GaN based layer, of the light emitting layer and the second-type GaN based layer.

4. The vertical light emitting device of claim 3, wherein the cover layer includes at least one of Si, O, and N.

5. The vertical light emitting device of claim 3, wherein the cover layer is a passivation layer.

6. The vertical light emitting device of claim 1, wherein the support layer is a metallic layer.

7. The vertical light emitting device of claim 6, wherein the metallic layer includes at least one of Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, Ti and Al.

8. A vertical light emitting device, comprising;

a support layer;

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

a first electrode disposed between the support layer and the first-type GaN based layer wherein the first electrode shares a common surface area with the first-type GaN based layer;

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;

wherein the light-emitting layer shares a common surface area with the first-type GaN based layer, and wherein the common surface area associated with the first electrode and the common surface area associated with the light-emitting layer are substantially the same size; 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.

9. The vertical light emitting device of claim 8, 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.

10. The vertical light emitting device of claim 8, further comprising a cover layer over at least one exposed portion of the first-type GaN based layer, the light emitting layer and the second-type GaN based layer.

11. The vertical light emitting device of claim 10, wherein the cover layer includes at least one of Si, O, and N.

12. The vertical light emitting device of claim 10, wherein the cover layer is a passivation layer.

13. The vertical light emitting device of claim 8, wherein the support layer is a metallic layer.

14. The vertical light emitting device according to claim 13, wherein the metallic layer includes at least one of Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, Ti and Al.

15. A vertical light emitting device, comprising;

a support layer;

a first electrode over the support layer;

a semiconductor layer having a multilayer structure;

a cover layer covering at least one exposed portion of the semiconductor layer, the cover layer is adapted to provide at least one of protection and insulation for the semiconductor layer; and

a second electrode over the semiconductor layer, wherein the first electrode and the second electrode are respectively located at opposite sides of the semiconductor layer, wherein the first electrode is a reflective layer configured to reflect light emitted from the semiconductor layer to enhance the light extraction capability of the device; and

wherein the support layer is a conductive layer.

16. The vertical light emitting device of claim 15, wherein the semiconductor layer includes:

a first-type GaN based layer;

an active layer over the first-type GaN based layer; and

a second-type GaN based layer over the active layer.

17. The vertical light emitting device of claim 15, wherein the cover layer is disposed higher than the second electrode.

18. The vertical light emitting device of claim 15, wherein the cover layer comprises material including at least one of Si, O, and N.

19. The vertical light emitting device of claim 16, wherein the cover layer surrounds at least two side portions of the first-type GaN based layer, of the active layer, and of the second-type GaN based layer.

20. A vertical light emitting device, comprising:

a support layer;

a first electrode over the support layer;

a semiconductor layer including a first-type layer, an active layer, and a second-type layer;

a passivation layer located between the support layer and the first-type layer of the semiconductor layer; and

a second electrode over the semiconductor layer, wherein the first electrode and the second electrode are respectively located at opposite sides of the semiconductor layer, and wherein the first electrode is a reflective layer configured to reflect light emitted from the semiconductor layer to enhance the light extraction capability of the device.

21. The vertical light emitting device of claim 20, wherein the passivation layer is located at a side of the first electrode.

22. The vertical light emitting device of claim 20, further comprising a metal layer between the support layer and the first electrode.

23. The vertical light emitting device of claim 22, wherein the passivation layer is located between the metal layer and the first-type layer of the semiconductor layer.

24. The vertical light emitting device of claim 20, wherein the passivation layer is positioned such that it is located over the second electrode.

25. The vertical light emitting device of claim 20, wherein the passivation layer comprises material including at least one of Si, O, and N.

26. The vertical light emitting device of claim 20, wherein the first-type layer is a p-type GaN based semiconductor layer.

27. The vertical light emitting device of claim 20, wherein the passivation layer is further located over at least one exposed portion of the semiconductor layer.

28. A vertical light emitting device, comprising;

a support layer;

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

a first electrode disposed between the support layer and the first-type GaN based layer;

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;

wherein an area between the light-emitting layer and the first-type GaN based layer is substantially the same size as an area between the first electrode and the first-type GaN based layer; 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.

29. The vertical light emitting device of claim 28, wherein the first-type CaN based layer is a p-CaN based layer and the second-type GaN based layer is an n-GaN based layer.

30. The vertical light emitting device of claim 28, further comprising a cover layer over at least one exposed portion of the first-type GaN based layer, the light emitting layer and the second-type GaN based layer.

31. The vertical light emitting device of claim 28, wherein the support layer is a metallic layer.

32. The vertical light emitting device according to claim 31, wherein the metallic layer includes at least one of Cu, Cr, Ni, Au, Ag, Mo, Pt, Pd, W, Ti and Al.