High efficiency light emitting diode

• US 9,136,432 B2
• Filed: 12/06/2011
• Issued: 09/15/2015
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Inventors: Yun, Jun Ho, Nam, Ki Bum, Lee, Joon Hee, Kim, Chang Youn, Yoo, Hong Jae, Hong, Sung Hoon
• Primary Examiner(s): Ho, Anthony
• Assistant Examiner(s): LAIR, SAMUEL L
• Application Number:
  US13/997,873
• Publication Number:
  US 20130292645A1
• Time in Patent Office: 1,379 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• 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 33/405 Reflective materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

Disclosed herein is a high efficiency light emitting diode. The light emitting diode includes: a semiconductor stack positioned over a support substrate; a reflective metal layer positioned between the support substrate and the semiconductor stack to ohmic-contact a p-type compound semiconductor layer of the semiconductor stack and having a groove exposing the semiconductor stack; a first electrode pad positioned on an n-type compound semiconductor layer of the semiconductor stack; an electrode extension extending from the first electrode pad and positioned over the groove region; and an upper insulating layer interposed between the first electrode pad and the semiconductor stack. In addition, the n-type compound semiconductor layer includes an n-type contact layer, and the n-type contact layer has a Si doping concentration of 5 to 7×10¹⁸/cm³ and a thickness in the range of 5 to 10 um.

Claims

1. A light emitting diode comprising:

a substrate;

a semiconductor stack disposed on the substrate, the semiconductor stack comprising a p-type compound semiconductor layer, an active layer, and an n-type compound semiconductor layer;

a reflective metal layer disposed between the substrate and the semiconductor stack and in ohmic contact with the p-type compound semiconductor layer, the reflective metal layer comprising a groove exposing a portion of the semiconductor stack;

a first electrode pad disposed on the n-type compound semiconductor layer;

an electrode extension extending from the first electrode pad and disposed over the groove; and

a first insulating layer disposed between a side surface of the first electrode pad and a side surface of the semiconductor stack,

wherein the n-type compound semiconductor layer comprises an n-type contact layer, and

wherein the n-type contact layer has an Si doping concentration of 5 to 7×

10¹⁸/cm³ and a thickness in the range of 5 to 10 μ

m.

2. The light emitting diode of claim 1, wherein the n-type compound semiconductor layer further comprises a superlattice layer disposed between the n-type contact layer and the active layer.

3. The light emitting diode of claim 2, wherein the superlattice layer comprises alternately stacked InGaN layers and GaN layers.

4. The light emitting diode of claim 3, wherein the superlattice layer has a higher resistivity than that of the n-type contact layer.

5. The light emitting diode of claim 1, further comprising a second insulating layer disposed in the groove and contacting the portion of the semiconductor stack exposed by the groove.

6. The light emitting diode of claim 5, further comprising a barrier metal layer disposed between the reflective metal layer and the substrate.

7. The light emitting diode of claim 6, wherein the reflective metal layer comprises plates separated by the groove.

8. The light emitting diode of claim 1, wherein a first portion of the semiconductor plates stack comprises a roughened surface, and

wherein the first insulating layer covers the roughened surface and comprises a concave-convex surface corresponding to the roughened surface.

9. The light emitting diode of claim 8, wherein a second portion of the semiconductor stack comprises a flat surface, and the first electrode pad and the electrode extension are disposed on the flat surface.

10. The light emitting diode of claim 9, wherein the electrode extension contacts the flat surface of the semiconductor stack.

11. A light emitting diode, comprising:

a substrate;

a semiconductor stack disposed on the substrate, the semiconductor stack comprising a p-type compound semiconductor layer, an active layer, and an n-type compound semiconductor layer;

a reflective metal layer disposed between the substrate and the semiconductor stack and in ohmic contact with the p-type compound semiconductor layer, the reflective metal layer and comprising a groove exposing a portion of the semiconductor stack;

a first electrode pad disposed on the n-type compound semiconductor layer;

an electrode extension extending from the first electrode pad and disposed over the groove; and

a first insulating layer disposed between a side surface of the first electrode pad and a side surface the semiconductor stack,

wherein the n-type compound semiconductor layer comprises an n-type contact layer and a first recovering layer disposed between the n-type contact layer and the active layer,

wherein the first recovering layer comprises an undoped layer or a low doped layer comprising a doping concentration lower than that of the n-type contact layer, and

wherein the n-type contact layer has a thickness in the range of 4.5 to 10 μ

m.

12. The light emitting diode of claim 11, wherein the first recovering layer has a thickness in the range of 100 to 200 nm.

13. The light emitting diode of claim 12, further comprising an electron injection layer disposed between the first recovering layer and the active layer.

14. The light emitting diode of claim 13, further comprising

a second recovering layer disposed between the first recovering layer and an electron supplementation layer;

and

an electron supplementation layer disposed between the first and second recovering layers.

15. The light emitting diode of claim 14, further comprising a superlattice layer disposed between the electron injection layer and the active layer.

16. The light emitting diode of claim 11, further comprising a second insulating layer disposed in the groove and contacting the portion of the semiconductor stack exposed by the groove.

17. The light emitting diode of claim 16, further comprising a barrier metal layer disposed between the reflective metal layer and the substrate.

18. The light emitting diode of claim 17, wherein the reflective metal layer comprises plates separated by the groove.

19. The light emitting diode of claim 11, wherein a first portion of the semiconductor stack comprises a roughened surface, and

wherein the first insulating layer covers the roughened surface and comprises a concave-convex surface corresponding to the roughened surface.

20. The light emitting diode of claim 19, wherein a second portion of the semiconductor stack comprises a flat surface, and the first electrode pad and the electrode extension are disposed on the flat surface.

21. The light emitting diode of claim 20, wherein the electrode extension contacts the flat surface of the semiconductor stack.