Light-emitting diode with improved light extraction efficiency

• US 10,243,109 B2
• Filed: 04/27/2018
• Issued: 03/26/2019
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Inventors: Lee, Jin Woong, Kim, Kyoung Wan, Yoon, Yeo Jin, Kim, Ye Seul
• Primary Examiner(s): Nguyen, Cuong Q
• Assistant Examiner(s): Kim, Tong-Ho
• Application Number:
  US15/965,757
• Publication Number:
  US 20180248081A1
• Time in Patent Office: 333 Days
• Field of Search: 257 98, 257 99
• 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 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

According to the present invention, a light-emitting diode with improved light extraction efficiency comprises: a semiconductor laminated structure including an N-layer, a light-emitting layer, and a P-layer formed on a substrate; an N-type electrode formed on the N-layer; and a P-type electrode formed on the P-layer, wherein the N-type electrode and the P-type electrode include a pad electrode and a dispersion electrode, and the N-type electrode and/or the P-type electrode includes a reflective electrode layer for reflecting light onto the dispersion electrode. Thus, the light-emitting diode has a reflective electrode layer on the electrode so as to improve light extraction efficiency. Further, a reflective layer is patterned beneath a pad unit, thus forming roughness and improving adhesion.

Claims

1. A light emitting diode (LED) device, comprising:

a substrate;

a light emitting structure formed over the substrate and including an N-layer, a light-emitting layer, and a P-layer;

an N-type electrode formed on the N-layer;

a P-type electrode formed on the P-layer;

a layer comprising SiO₂ disposed between the P-layer and P-type electrode and patterned to form a roughness on the P-layer;

a transparent electrode disposed between the P-layer and P-type electrode and positioned to cover at least a portion of the layer comprising SiO₂; and

wherein the transparent electrode is shaped to conform to a contour of at least of the layer comprising SiO₂,

wherein the layer comprising SiO₂ includes portions that are located apart from one another,

wherein the portions of the layer comprising SiO₂ include a first portion having a side surface and a top surface that are covered by the transparent electrode, and a second portion having a top surface covered by the transparent electrode and a side surface not covered by the transparent electrode.

2. The light emitting diode device of claim 1, wherein the transparent electrode has a surface having a first portion and a second portion located lower than that of the first portion.

3. The light emitting diode device of claim 1, wherein the transparent electrode is disposed between the portions of the layer comprising SiO₂.

4. The light emitting diode device of claim 1, wherein the P-type electrode is disposed between the portions of the layer comprising SiO₂.

5. The light emitting diode device of claim 1, wherein each of the N-type electrode and the P-type electrode includes a pad electrode and a dispersion electrode that are adjacent each other in a direction parallel to a surface of the substrate.

6. The light emitting diode device of claim 5, wherein the layer comprising SiO₂ is formed under at least one of the pad electrodes of the N-type electrode and the P-type electrode.

7. The light emitting diode device of claim 1, wherein at least one of the N-type electrode and the P-type electrode has a surface having a first portion and a second portion located lower than that of the first portion.

8. A light emitting diode (LED) device, comprising:

a substrate;

a light emitting structure disposed over the substrate and including an N-layer, a light-emitting layer, and a P-layer and configured to emit light in response to an electrical current through the N-layer and the P-layer;

a layer comprising SiO₂ disposed on the light emitting structure and patterned to include an exposure region to expose the P-layer;

an N-type electrode disposed on the N-layer and electrically connected to the N-layer to conduct the electrical current;

a transparent electrode disposed on the P-layer and the layer comprising SiO₂ and having a roughness formed on a surface of the transparent electrode, the roughness caused by the layer comprising SiO₂, and

a P-type electrode disposed on the transparent electrode and electrically connected to the P-layer to conduct the electrical current,

wherein the layer comprising SiO₂ includes an additional exposure region to exposure the P-layer and the layer comprising SiO₂ includes portions that are located apart from one another by the exposure region and the additional exposure region,

wherein the portions of the layer comprising SiO₂ include a first portion having a side surface and a top surface that are covered by the transparent electrode, and a second portion having a top surface covered by the transparent electrode and a side surface not covered by the transparent electrode.

9. The light emitting diode device of claim 8, wherein the transparent electrode includes indium-tin-oxide (ITO).

10. The light emitting diode device of claim 8, wherein the substrate has a roughened surface.

11. The light emitting diode device of claim 8, wherein the transparent electrode has a portion filled in the exposure region.

12. The light emitting diode device of claim 8, wherein the P-type electrode has a portion filled in the exposure region.

13. The light emitting diode device of claim 8, wherein the P-type electrode has a surface having a first portion and a second portion located lower than that of the first portion.

14. The light emitting diode device of claim 8, wherein the P-type electrode includes a pad electrode and a dispersion electrode that are adjacent each other in a direction parallel to a surface of the substrate.

15. The light emitting diode device of claim 14, wherein the transparent electrode has a portion covering side surfaces of the layer comprising SiO₂, the portion being located on the P-layer and under the dispersion electrode.

16. A light emitting diode (LED) device, comprising:

a substrate;

a light emitting structure disposed over the substrate and including an N-layer, a light-emitting layer, and a P-layer and configured to emit light in response to an electrical current through the N-layer and the P-layer;

an N-type electrode formed on the N-layer;

a P-type electrode formed on the P-layer;

a layer comprising SiO₂ disposed on the light emitting structure and patterned to include an exposure region to expose the P-layer;

a transparent electrode disposed between the P-layer and P-type electrode and positioned to cover at least a portion of the layer comprising SiO₂;

a reflective layer disposed on the P-type electrode;

an antioxidant film disposed on the reflective layer and positioned to cover at least a portion of the reflective layer; and

wherein each of the reflective layer and the antioxidant film has a surface having a first portion and a second portion that are separated by different distances from the substrate.

17. The light emitting diode device of claim 16, further comprising an adhesive layer disposed between the reflective layer and antioxidant film and including Ti.

18. The light emitting diode device of claim 16, wherein the antioxidant film includes transparent and insulating material that allows light generated from the light emitting structure to transmit.

19. The light emitting diode device of claim 16, wherein the second portion is located lower than the first portion.