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

• US 20090272971A1
• Filed: 06/10/2009
• Published: 11/05/2009
• 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: Yves, Lacroix, Yoon, Hyung Soo, Lee, Young Ju, LEE, Chung Hoon
• Granted Patent: US 8,227,272 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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 submount substrate; and

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

wherein each light emitting cell has a surface opposite to the submount substrate, the surface formed by removing a growth substrate for growing the N-type semiconductor layer and the P-type semiconductor layer.

2. The light emitting device of claim 1, wherein each light emitting cell further comprises an 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 light emitting device of claim 1, wherein the metal layer comprises an ohmic metal layer and a reflective layer.

4. The light emitting device of claim 1, wherein an N-type semiconductor layer and a P-type semiconductor layer of two adjacent light emitting cells among the plurality of light emitting cells are electrically connected to each other.

5. The light emitting device of claim 4, wherein the submount substrate comprises a plurality of electrode layers spaced apart from one another, each electrode layer electrically connecting the N-type semiconductor layer and the P-type semiconductor layer of two adjacent light emitting cells among the plurality of light emitting cells,

wherein the submount substrate comprises a plurality of concave portions and a plurality of convex portions,

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, and

wherein each electrode layer extends from a concave portion to a convex portion.

6. 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

removing portions of the first substrate, wherein the plurality of light emitting cells are thereby separated from each other.

7. The method of claim 6, 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).

8. The method of claim 6, 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.

9. A light emitting device, comprising:

a submount substrate; and

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

wherein each light emitting cell comprises a base substrate opposite to the submount substrate, the N-type semiconductor layer, the P-type semiconductor layer, and the metal layer of each light emitting cell is interposed between the base substrate and the submount substrate, and the base substrate of each light emitting cell is spaced apart from the base substrate of every other light emitting cell.

10. The light emitting device of claim 9, wherein each light emitting cell further comprises an 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).

11. The light emitting device of claim 9, wherein the metal layer comprises an ohmic metal layer and a reflective layer.

12. The light emitting device of claim 9, wherein an N-type semiconductor layer and a P-type semiconductor layer of two adjacent light emitting cells among the plurality of light emitting cells are electrically connected to each other.

13. The light emitting device of claim 12, wherein the submount substrate comprises a plurality of electrode layers spaced apart from one another, each electrode layer electrically connecting the N-type semiconductor layer and the P-type semiconductor layer of two adjacent light emitting cells among the plurality of light emitting cells,

wherein the submount substrate comprises a plurality of concave portions and a plurality of convex portions,

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, and

wherein each electrode layer extends from a concave portion to a convex portion.

14. The light emitting device of claim 9, wherein the base substrate comprises Al₂O₃, SiC, ZnO, Si, GaAs, GaP, LiAl₂O₃, BN, AlN, or GaN.