Vertical nitride based semiconductor light emitting device having improved light extraction efficiency

• US 8,373,184 B2
• Filed: 05/10/2006
• Issued: 02/12/2013
• Est. Priority Date: 05/19/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hong, Jin Young, Suh, Hyo Won
• Primary Examiner(s): SAYADIAN, HRAYR
• Application Number:
  US11/430,982
• Publication Number:
  US 20060261323A1
• Time in Patent Office: 2,470 Days
• Field of Search: 257/98, 257/E33.028, 257/E33.074
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/05124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05139 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05164 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05166 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05171 Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/0558 being stacked
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05639 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05664 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05666 Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/05671 Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• 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 33/22 : Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 : containing nitrogen

Abstract

The invention provides a nitride semiconductor light emitting device. In the invention, a first conductivity-type nitride semiconductor layer is formed on a conductive substrate having light transmissibility. An active layer is formed on the first conductivity-type nitride semiconductor layer. Also, a second conductivity-type nitride semiconductor layer is formed on the active layer. Further, a conductive light scattering layer made of a conductive material is formed on an underside of the substrate. The conductive light scattering layer has light transmissibility of 70% or more and has a rough pattern formed on an outer surface to scatter light.

Claims

1. A vertical nitride semiconductor light emitting device comprising:

a conductive substrate having first and second opposing sides;

a first conductivity-type nitride semiconductor layer;

an active layer disposed on the first conductivity-type nitride semiconductor layer;

a second conductivity-type nitride semiconductor layer disposed on the active layer;

a light scattering layer disposed on the first side of the conductive substrate, the light scattering layer being made of a different material from that of the conductive substrate, the material having a light transmissibility of 70% or more and having a rough pattern disposed on an outer surface to scatter light, wherein the light scattering layer has a refractivity of 1.5 to 2.4, and a critical angle of 36.8 to 73.7;

a first electrode disposed on the light scattering layer having a rough pattern, wherein the light scattering layer and the first electrode are disposed on the same side of the conductive substrate; and

a second electrode disposed on the second conductivity-type nitride layer, wherein the second electrode is disposed on the second side of the conductive substrate and the second electrode includes a reflective metal layer,

wherein the light scattering layer extends from the conductive substrate to at least partially cover sides of the nitride light emitting device.

2. The vertical nitride semiconductor light emitting device according to claim 1, wherein the light scattering layer comprises one selected from a group consisting of Indium Tin Oxide, SnO₂, Ga₂O₃, ZnO, MgO and In₂O₃.

3. The vertical nitride semiconductor light emitting device according to claim 1, wherein the rough pattern of the light scattering layer comprises microstructural features which are spaced from each other in the range of about 0.001 μ

m to 10 μ

m.

4. The vertical nitride semiconductor light emitting device according to claim 1, further comprising an insulating layer formed between the light scattering layer covering the sides of the device, and the second conductivity-type nitride layer and the active layer.

5. The vertical nitride semiconductor light emitting device according to claim 1, wherein the reflective metal layer comprises at least one selected from a group consisting of Ag, Al, Rh, Ru, Pt, Au, Cu, Pd, Cr, Ni, Co, Ti, In and Mo and alloys thereof.