LIGHT EMITTING DEVICE HAVING A PLURALILTY OF LIGHT EMITTING CELLS AND PACKAGE MOUNTING THE SAME

• US 20110175129A1
• Filed: 03/29/2011
• Published: 07/21/2011
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: LEE, Young Ju, YOON, Hyung Soo, LEE, Chung Hoon, YVES, Lacroix
• Granted Patent: US 8,643,029 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

Disclosed is a light emitting device having a plurality of light emitting cells and a package having the same mounted thereon. The light emitting device includes a plurality of light emitting cells which are formed on a substrate and each of which has an N-type semiconductor layer and a P-type semiconductor layer located on a portion of the N-type semiconductor layer. The plurality of light emitting cells are bonded to a submount substrate. Accordingly, heat generated from the light emitting cells can be easily dissipated, so that a thermal load on the light emitting device can be reduced. Meanwhile, since the plurality of light emitting cells are electrically connected using connection electrodes or electrode layers formed on the submount substrate, it is possible to provide light emitting cell arrays connected to each other in series. Further, it is possible to provide a light emitting device capable of being directly driven by an AC power source by connecting the serially connected light emitting cell arrays in reverse parallel to each other.

Claims

1. A light emitting device, comprising:

a substrate;

a nitride semiconductor light emitting cell mounted on the substrate, a top surface of the nitride semiconductor light emitting cell comprising an n-type nitride semiconductor layer or an un-doped nitride semiconductor layer, a bottom surface of the nitride semiconductor light emitting cell comprising a p-type nitride semiconductor layer and a partially exposed n-type nitride semiconductor layer;

a passivation layer arranged between the substrate and the nitride semiconductor light emitting cell;

a first metal layer arranged between the substrate and the nitride semiconductor light emitting cell, the first metal layer contacting the bottom surface of the nitiride semiconductor light emitting cell; and

a bonding pad connected to the first metal layer, the bonding pad arranged on a portion of the substrate and extending outside of a region under the light emitting cell.

2. The light emitting device of claim 1, further comprising a transparent layer covering the top surface of the nitride semiconductor light emitting cell, wherein the transparent layer comprises Al₂O₃, Si, SiC, ZnO, GaAs, GaP, LiAl₂O₃, BN, AN, or GaN.

3. The light emitting device of claim 1, wherein the substrate comprises a conductive material.

4. The light emitting device of claim 3, wherein the conductive material comprises SiC, Si, Ge, SiGe, AN, or metal.

5. The light emitting device of claim 1, wherein the passivation layer comprises SiO₂, MgO, or SiN.

6. The light emitting device of claim 1, further comprising an additional first metal layer arranged between the first metal layer and the p-type bonding pad, wherein the additional first metal layer comprises Ti, Ni, Ag, Zn, Cd, Bi, Cu, Ge, Au, Sn, or Pb.

7. The light emitting device of claim 1, wherein the first metal layer comprises indium tin oxide (ITO).

8. The light emitting device of claim 1, wherein the first metal layer comprises a reflective film.

9. The light emitting device of claim 6, further comprising a second metal layer and an additional second metal layer.

10. The light emitting device of claim 9, wherein the second metal layer contacts the n-type nitride semiconductor layer or is adjacent to the p-type nitride semiconductor layer.

11. The light emitting device of claim 9, wherein the additional second metal layer comprises Ti, Ni, Ag, Zn, Cd, Bi, Cu, Ge, Au, Sn, or Pb.

12. The light emitting device of claim 9, wherein the additional second metal layer comprises an electrode layer.

13. The light emitting device of claim 1, further comprising:

a second nitride semiconductor light emitting cell; and

an electrode layer connecting the nitride semiconductor light emitting cell and the second nitride semiconductor light emitting cell in parallel.

14. The light emitting device of claim 1, further comprising:

a second nitride semiconductor light emitting cell; and

an electrode layer connecting the nitride semiconductor light emitting cell and the second nitride semiconductor light emitting cell in series.

15. The light emitting device of claim 6, wherein the additional first metal layer is arranged on the n-type nitride semiconductor layer, and connects the n-type nitride semiconductor layer to the bottom surface of the substrate.

16. The light emitting device of claim 1, further comprising a molding member arranged on the nitride semiconductor light emitting cell.

17. The light emitting device of claim 16, further comprising a fluorescent substance or a diffusing substance disposed in the molding member.

18. The light emitting device of claim 16, further comprising a fluorescent substance disposed between the molding member and the light emitting device.

19. The light emitting device of claim 1, further comprising a heat sink, wherein the substrate is arranged on the heat sink.

20. The light emitting device of claim 19, wherein the heat sink is exposed through bottom surface of the light emitting device.