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

• US 8,227,272 B2
• Filed: 06/10/2009
• Issued: 07/24/2012
• 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): Smith, Zandra
• Assistant Examiner(s): Joy, Jeremy J
• Application Number:
  US12/481,998
• Publication Number:
  US 20090272971A1
• Time in Patent Office: 1,140 Days
• Field of Search: 257/14, 257/88, 257 98- 99, 257/103, 257/623, 257/676, 257/778, 257E33055-E33059, 257E33062-E33066, 438/22, 438/34
• US Class Current: 438/28
• 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 method of fabricating a light emitting device, comprising:

forming a plurality of light emitting cells on a first substrate, each light emitting cell comprising an N-type semiconductor layer, a P-type semiconductor layer arranged on a portion of the N-type semiconductor layer, and a metal layer arranged on the P-type semiconductor layer;

bonding the first substrate comprising the plurality of light emitting cells to a second substrate; and

after bonding the first substrate to the second substrate, removing portions of the first substrate, wherein the plurality of light emitting cells are thereby separated from each other such that the light emitting device comprises the second substrate and the plurality of separated light emitting cells disposed on the second substrate,

wherein at least two light emitting cells among the plurality of light emitting cells are electrically connected to each other before portions of the first substrate are removed.

2. The method of claim 1, further comprising forming an active layer, wherein each light emitting cell comprises the active layer interposed between the P-type semiconductor layer and the N-type semiconductor layer, the active layer comprising Al_xIn_yGa_1-x-yN(0≦

x+y≦

1).

3. The method of claim 1, further comprising:

forming a plurality of concave portions and a plurality of convex portions in the second substrate; and

forming a plurality of electrode layers on the second substrate, the respective electrode layers being extended from the concave portions to the convex portions,

wherein bonding the first substrate comprising the plurality of light emitting cells to the second substrate comprises bonding the plurality of light emitting cells to the electrode layers such that each electrode layer electrically connects an N-type semiconductor layer and a P-type semiconductor layer of two adjacent light emitting cells among the plurality of light emitting cells, and

wherein the N-type semiconductor layers are electrically connected to the convex portions, and the P-type semiconductor layers are electrically connected to the concave portions, respectively.

4. The method of claim 1, wherein the metal layer comprises an ohmic metal layer.

5. The method of claim 1, wherein the first substrate comprises Al₂O₃, SiC, ZnO, Si, GaAs, GaP, LiAl₂O₃, BN, AlN, or GaN.

6. The method of claim 1, wherein after removing portions of the first substrate, each light emitting cell comprises an exposed surface opposite to, and not facing, the second substrate, and the entire exposed surface comprises the N-type semiconductor layer only or a buffer layer only.

7. The method of claim 1, further comprising a second metal layer arranged on the P-type semiconductor layer and the N-type semiconductor layer.

8. The method of claim 7, wherein the second metal layer comprises a reflective layer with reflectivity of 10% to 100%.