LIGHT EMITTING DIODE CHIP AND METHOD OF FABRICATING THE SAME

• US 20120161176A1
• Filed: 03/28/2011
• Published: 06/28/2012
• Est. Priority Date: 12/24/2010
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: JIN, Sang Ki, KIM, Jong Kyu, LEE, Sum Geun, HEO, Min Chan, SHIN, Jin Cheol, LEE, So Ra
• Granted Patent: US 8,314,440 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/73265 Layer and wire connectors
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2933/0025 relating to coatings
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Exemplary embodiments of the present invention provide light emitting diode (LED) chips and a method of fabricating the same. An LED chip according to an exemplary embodiment includes a substrate; a light emitting structure arranged on the substrate, and an alternating lamination bottom structure arranged under the substrate. The alternating lamination bottom structure includes a plurality of dielectric pairs, each of the dielectric pairs including a first material layer having a first refractive index and a second material layer having a second refractive index, the first refractive index being greater than the second refractive index.

Claims

1. A light emitting diode (LED) chip, comprising:

a substrate;

a light emitting structure arranged on the substrate, the light emitting structure comprising a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer disposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer; and

an alternating lamination bottom structure, the substrate arranged on the alternating lamination bottom structure, the alternating lamination bottom structure comprising a plurality of dielectric pairs, each of the dielectric pairs comprising a first material layer comprising a first refractive index and a second material layer comprising a second refractive index, the first refractive index being greater than the second refractive index, the plurality of dielectric pairs comprising;

a plurality of first dielectric pairs comprising the first material layer and the second material layer, the first material layer and the second material layer each comprising an optical thickness less than λ

/4;

a second dielectric pair comprising the first material layer and the second material layer, one of the first material layer and the second material layer comprising an optical thickness less than λ

/4 and the other comprising an optical thickness greater than λ

/4; and

a plurality of third dielectric pairs comprising the first material layer and the second material layer, each of the first material layer and the second material layer comprising an optical thickness greater than λ

/4,

wherein λ

is a central wavelength of the visible light range.

2. The LED chip of claim 1, wherein all of the first dielectric pairs are located closer or farther from the substrate than any of the third dielectric pairs.

3. The LED chip of claim 2, wherein the second dielectric pair separates the plurality of first dielectric pairs and the plurality of third dielectric pairs.

4. The LED chip of claim 1, wherein at least half the plurality of first dielectric pairs are arranged closer to the substrate than the second dielectric pair, at least half the plurality of third dielectric pairs are located farther from the substrate than the second dielectric pair.

5. The LED chip of claim 1, wherein at least 80% of the plurality of first dielectric pairs are located closer to the substrate than the second dielectric pair, and at least 80% of the plurality of third dielectric pairs are located farther from the substrate than the second dielectric pair.

6. The LED chip of claim 1, wherein the plurality of first dielectric pairs are arranged closer to the substrate than the plurality of third dielectric pairs.

7. The LED chip of claim 1, wherein at least half the plurality of third dielectric pairs are arranged closer to the substrate than the second dielectric pair, and at least half the plurality of first dielectric pairs are arranged farther from the substrate than the second dielectric pair.

8. The LED chip of claim 1, wherein the plurality of first dielectric pairs are located farther from the substrate than the plurality of third dielectric pairs.

9. The LED chip of claim 1, further comprising:

an alternating lamination top structure arranged on the light emitting structure, the alternating lamination top structure to transmit light generated in the active layer and to reflect light within at least a partial region of the visible light spectrum, the reflected light comprising a longer wavelength than light generated in the active region.

10. The LED chip of claim 9, wherein the top structure comprises a transmittance of at least 90% with respect to light generated in the active layer.

11. The LED chip of claim 10, further comprising:

an electrode pad electrically connected to the second conductivity type semiconductor layer; and

an alternating lamination under structure disposed between the second conductivity type semiconductor layer and the electrode pad, the alternating lamination under structure to reflect light generated in the active layer.

12. The LED chip of claim 11, further comprising a metal reflector, the alternating lamination bottom structure being arranged on the metal reflector.

13. The LED chip of claim 12, wherein the alternating lamination bottom structure or a combination of the alternating lamination bottom structure and the metal reflector comprises a reflectance of at least 90% with respect to light generated in the active layer and that enters the alternating lamination bottom structure at an angle of incidence of 0 degrees to 60 degrees.

14. A method of fabricating a light emitting diode chip, the method comprising;

forming at least one light emitting structure on a first surface of a substrate; and

forming an alternating lamination bottom structure on a second surface of the substrate, the second surface being on an opposite side of the substrate as the first surface, the alternating lamination bottom structure comprising a plurality of dielectric pairs, each of the dielectric pairs comprising a first material layer comprising a first refractive index and a second material layer comprising a second refractive index, the first refractive index being greater than the second refractive index, the plurality of dielectric pairs comprising;

a plurality of first dielectric pairs comprising the first material layer and the second material layer, the first material layer and the second material layer each comprising an optical thickness less than λ

/4;

a second dielectric pair comprising the first material layer and the second material layer, one of the first material layer and the second material layer comprising an optical thickness less than λ

/4 and the other comprising an optical thickness greater than λ

/4; and

a plurality of third dielectric pairs comprising the first material layer and the second material layer, each of the first material layer and the second material layer comprising an optical thickness greater than λ

/4,

wherein λ

is a central wavelength of the visible light range.

15. The method of claim 14, wherein forming the alternating lamination bottom structure comprises determining an optical thickness of each layer in the plurality of dielectric pairs and a lamination sequence of the plurality of dielectric pairs, and sequentially forming the respective layers on the substrate according to the lamination sequence.

16. The method of claim 14, wherein the plurality of first dielectric pairs is arranged closer to or farther from the substrate than the plurality of third dielectric pairs.

17. The method of claim 16, wherein the second dielectric pair is arranged near a center of the alternating lamination bottom structure.

18. The method of claim 14, wherein at least half the plurality of first dielectric pairs are located closer to the substrate than a second dielectric pair located closest to the substrate and such that at least half the plurality of third dielectric pairs are located farther from the substrate than a second dielectric pair farthest from the substrate.

19. The method of claim 14, wherein at least half the plurality of third dielectric pairs are located closer to the substrate than a second dielectric pair located closest to the substrate and such that at least half the plurality of first dielectric pairs are located farther from the substrate than a second dielectric pair located farthest from the substrate.

20. The method of claim 14, further comprising forming an alternating lamination top structure on the light emitting structure, the top structure to transmit light generated in the active layer and to reflect light within at least a partial region of the visible light spectrum, the reflected light comprising a longer wavelength than light generated in the active region.