Light emitting device having a plurality of light emitting cells and package mounting the same

• US 8,643,029 B2
• Filed: 03/29/2011
• Issued: 02/04/2014
• 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, Chung Hoon, Yves, Lacroix, Yoon, Hyung Soo, Lee, Young Ju
• Primary Examiner(s): Lee, Cheung
• Assistant Examiner(s): Joy, Jeremy
• Application Number:
  US13/074,761
• Publication Number:
  US 20110175129A1
• Time in Patent Office: 1,043 Days
• Field of Search: 257/88, 257/43, 257/98, 257/77, 257/E33.045, 257/E29.068, 257/E21.002, 257/E33.013, 257/778, 257/E33.055, 257/E33.062, 257/E33.066, 438/34, 438/22, 438/26
• US Class Current: 257/88
• 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 plurality of serially connected nitride semiconductor light emitting cells mounted on the substrate, a top surface of each nitride semiconductor light emitting cell comprising an n-type nitride semiconductor layer or an un-doped nitride semiconductor layer, a bottom surface of each nitride semiconductor light emitting cell comprising a p-type nitride semiconductor layer and a partially exposed n-type nitride semiconductor layer;

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

a first bonding pad connected to the first metal layer of a first nitride semiconductor light emitting cell of the plurality of nitride semiconductor light emitting cells, the first bonding pad penetrating through the substrate;

a second metal layer contacting each partially exposed n-type nitride semiconductor layer;

a second bonding pad connected to the second metal layer of a second nitride semiconductor light emitting cell of the plurality of nitride semiconductor light emitting cells, the second bonding pad penetrating through the substrate; and

a plurality of connection electrodes respectively electrically connecting the n-type nitride semiconductor layers and the p-type nitride semiconductor layers of adjacent nitride semiconductor light emitting cells, the connection electrodes contacting the substrate,

wherein the first nitride semiconductor light emitting cell and the second nitride semiconductor light emitting cell are respectively arranged at a first end and a second end of the serially connected nitride semiconductor light emitting cells.

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

wherein the transparent layer comprises a ground surface.

3. The light emitting device of claim 1, further comprising an additional first metal layer arranged between the first metal layer and the first bonding pad.

4. The light emitting device of claim 3, wherein the additional first metal layer comprises Ti, Ni, Ag, Zn, Cd, Bi, Cu, Ge, Au, Sn, or Pb.

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

6. The light emitting device of claim 1, further comprising a reflective film arranged on the first metal layer.

7. The light emitting device of claim 4, further comprising an additional second metal layer arranged between the second metal layer and the substrate.

8. The light emitting device of claim 7, wherein the additional second metal layer contacts the second metal layer.

9. The light emitting device of claim 1, wherein the second metal layer comprises Ti, Ni, Ag, Zn, Cd, Bi, Cu, Ge, Au, Sn, or Pb.

10. The light emitting device of claim 7, wherein the additional second metal layer comprises an electrode layer.

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

12. The light emitting device of claim 11, further comprising a fluorescent substance or a diffusing substance disposed in the molding member.

13. The light emitting device of claim 11, further comprising a fluorescent substance disposed between the molding member and the light emitting device.

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

15. The light emitting device of claim 14, wherein the heat sink is exposed through a bottom surface of the light emitting device.

16. A light emitting device, comprising:

a substrate;

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

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

a first bonding pad connected to the first metal layer of a first nitride semiconductor light emitting cell of the plurality of nitride semiconductor light emitting cells, the bonding pad arranged on a portion of the substrate and extending outside of a region under the plurality of nitride semiconductor light emitting cells;

a second metal layer contacting each partially exposed n-type nitride semiconductor layer;

a second bonding pad connected to the second metal layer of a second nitride semiconductor light emitting cell of the plurality of nitride semiconductor light emitting cells, the second bonding pad arranged on a portion of the substrate and extending outside of a region under the plurality of nitride semiconductor light emitting cells; and

a plurality of connection electrodes respectively electrically connecting the n-type nitride semiconductor layers and the p-type nitride semiconductor layers of adjacent nitride semiconductor light emitting cells, the connection electrodes contacting the substrate,

wherein the first nitride semiconductor light emitting cell and the second nitride semiconductor light emitting cell are respectively arranged at a first end and a second end of the serially connected nitride semiconductor light emitting cells.

17. The light emitting device of claim 16, further comprising an additional first metal layer arranged between the first metal layer of the first nitride semiconductor light emitting cell and the first bonding pad.

18. The light emitting device of claim 17, further comprising an additional second metal layer arranged between the second metal layer of the first nitride semiconductor light emitting cell and the substrate.