LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE PACKAGE

• US 20130328056A1
• Filed: 03/14/2013
• Published: 12/12/2013
• Est. Priority Date: 06/07/2012
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: KWON, Oh Min, WON, Jong Hak, BAEK, Kwang Sun, SEO, Heon Jin
• Granted Patent: US 9,082,929 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

Disclosed is a light emitting device including a substrate, a buffer layer on the substrate, and a light-emitting structure on the buffer layer. The buffer layer has a refractive index decreased toward the substrate from the light-emitting structure.

Claims

1. A light emitting device comprising:

a substrate;

a buffer layer on the substrate; and

a light-emitting structure on the buffer layer,

wherein the buffer layer has a refractive index decreased toward the substrate from the light-emitting structure.

2. The light emitting device of claim 1, wherein the buffer layer comprises a plurality of sub-layers, and the sub-layers have refractive indexes different from each other.

3. The light emitting device of claim 2, wherein the refractive index of each sub-layer is decreased toward the substrate from the light-emitting structure.

4. The light emitting device of claim 2, wherein an Al content of each sub-layer is decreased toward the substrate from the light-emitting structure.

5. The light emitting device of claim 2, wherein each sub-layer includes a compound semiconductor material having a refractive index smaller than a refractive index of the light-emitting structure and greater than a refractive index of the substrate.

6. The light emitting device of claim 5, wherein the sub-layer includes Al_xGa_(1-x)N in which 0≦

x≦

1.

7. The light emitting device of claim 5, wherein the sub-layer includes Al_xGa_(1-x)N in which 0≦

x≦

1.

8. The light emitting device of claim 2, wherein the sub-layers have Al contents different from each other.

9. The light emitting device of claim 2, wherein a difference in the refractive index between individual sub-layers is variable.

10. The light emitting device of claim 2, wherein a thickness of each sub-layer is variable.

11. The light emitting device of claim 1, wherein variation in the refractive index of the buffer layer from the light-emitting structure to a portion corresponding to a half of a thickness of the buffer layer is greater than variation in the refractive index of the buffer layer from the portion corresponding to the half of the thickness of the buffer layer to the substrate.

12. The light emitting device of claim 1, wherein variation in the refractive index of the buffer layer from the light-emitting structure to a portion corresponding to a half of a thickness of the buffer layer is smaller than variation in the refractive index of the buffer layer from the portion corresponding to the half of the thickness of the buffer layer to the substrate.

13. The light emitting device of claim 1, further comprising a plurality of protrusions on the substrate.

14. The light emitting device of claim 13, wherein the buffer layer is disposed on the substrate between the protrusions.

15. The light emitting device of claim 13, wherein each protrusion extends upwardly from a top surface of the substrate.

16. A light emitting device comprising:

a substrate;

a buffer layer on the substrate; and

a conductive semiconductor layer on the buffer layer,

wherein the buffer layer comprises a plurality of sub-layers, and a refractive index of each sub-layer is decreased toward the substrate from the light-emitting structure.

17. The light emitting device of claim 16, wherein the sub-layer includes Al_xGa_(1-x)N in which 0≦

x≦

1.

18. The light emitting device of claim 16, wherein the sub-layer adjacent to the substrate has a maximum Al content.

19. The light emitting device of claim 16, further comprising a plurality of protrusions on the substrate, wherein each protrusion extends upwardly from a top surface of the substrate.

20. The light emitting device of claim 19, wherein the protrusion has a thickness greater than a thickness of the buffer layer.