Light-emitting device

• US 10,224,462 B2
• Filed: 07/23/2014
• Issued: 03/05/2019
• Est. Priority Date: 04/05/2008
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Song, June O.
• Primary Examiner(s): Chen, Yu
• Application Number:
  US14/339,205
• Publication Number:
  US 20140332803A1
• Time in Patent Office: 1,686 Days
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

Disclosed is a light emitting device. The light emitting device includes a light emitting semiconductor layer including a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer and a second conductive semiconductor layer on the active layer. A passivation layer is disposed on a surface of a light emitting semiconductor layer. A first electrode layer is disposed on the first conductive semiconductor layer and a second electrode layer is disposed on the second conductive semiconductor layer. Plurality of protrusion parts are disposed on a top surface of the first conductive semiconductor layer.

Claims

1. A light emitting device comprising:

a light emitting semiconductor layer including a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer and a second conductive semiconductor layer on the active layer;

a passivation layer disposed on a surface of the light emitting semiconductor layer;

a light extracting structure layer on a top surface of the passivation layer and on lateral surfaces of the passivation layer, the light extracting structure layer includes a first material different from a second material of the passivation layer, wherein a concave-convex structure is provided on a top surface of the light extracting structure layer, the top surface of the light extracting structure layer faces away from the passivation layer;

a first electrode layer disposed on a top surface of the first conductive semiconductor layer, the first electrode layer having a lateral surface, a top surface and a bottom surface;

a support substrate disposed under a bottom surface of the second conductive semiconductor layer, the support substrate having a top surface and a bottom surface, the support substrate is an electric conductive layer having a wafer substrate including at least one of Si, SiGe, ZnO, GaN, AlSiC and GaAs;

a current spreading layer disposed between the bottom surface of the second conductive semiconductor layer and the top surface of the support substrate;

a plurality of protrusion parts disposed on the top surface of the first conductive semiconductor layer; and

a second electrode layer disposed under the bottom surface of the support substrate, the second electrode layer including a material forming an interface having an adhesive property and an ohmic contact interface with respect to the support substrate, the second electrode layer being a different structure than the support substrate,

wherein the plurality of protrusion parts include an identical material from the first conductive semiconductor layer,

wherein the passivation layer includes a first portion disposed on the plurality of protrusion parts and a second portion disposed on lateral surfaces of the light emitting semiconductor layer,

wherein the support substrate is electrically connected to the second electrode layer and the current spreading layer,

wherein a width of the second electrode layer is wider than a width of the light emitting semiconductor layer in a horizontal direction, and

wherein the bottom surface of the first electrode layer physically contacts the first conductive semiconductor layer,

wherein the first portion of the passivation layer is disposed around the first electrode layer and is spaced apart from the lateral surface of the first electrode layer,

wherein the lateral surface of the first electrode layer does not physically contact the first portion of the passivation layer, the lateral surface of the first electrode layer does not physically contact the light extracting structure layer, and the lateral surface of the first electrode layer faces a side surface of the first portion of the passivation layer,

wherein the second portion of the passivation layer contacts the current spreading layer,

wherein an entire area of the first electrode layer is formed of a metal and physically contacts the first conductive semiconductor layer,

wherein the first conductive semiconductor layer and the second conductive semiconductor layer includes a nitride-based semiconductor material,

wherein the side surface of the first portion of the passivation layer is spaced apart from the lateral surface of the first electrode layer,

wherein the protrusion parts are not disposed between the side surface of the first portion of the passivation layer and the lateral surface of the first electrode layer,

wherein the first material of the light extracting structure layer having a vertical side surface that is aligned with the side surface of the first portion of the passivation layer facing the lateral surface of the first electrode layer and a side surface of the protrusion parts, and

the light emitting device comprising an exposed region of the first conductive semiconductor layer that is disposed at an area between the side surface of the first portion of the passivation layer and the lateral surface of the first electrode layer facing the first portion of the passivation layer.

2. The light emitting device of claim 1, wherein the first portion of the passivation layer includes a concave-convex structure contacting the plurality of protrusion parts, wherein the top surface of the first conductive semiconductor layer includes the exposed region that is not overlapped in a vertical direction with the bottom surface of the first electrode layer and is not overlapped with the first portion of the passivation layer in the vertical direction.

3. The light emitting device of claim 2, wherein the passivation layer includes a transparent electric insulating material, and the current spreading layer includes a metal material.

4. The light emitting device of claim 1, wherein the second electrode layer directly contacts the support substrate, and the second electrode layer is formed of a metal.

5. The light emitting device of claim 1, wherein the passivation layer surrounds the current spreading layer.

6. A light emitting device comprising:

a support substrate formed of a conductive material, the support substrate having a top surface and a bottom surface, the support substrate is an electric conductive layer having a wafer substrate including at least one of Si, SiGe, ZnO, GaN, AlSiC and GaAs;

a light emitting semiconductor layer including a second conductive semiconductor layer on the support substrate, an active layer on the second conductive semiconductor layer, and a first conductive semiconductor layer on the active layer;

a plurality of protrusion parts disposed on the first conductive semiconductor layer and including an identical material from the first conductive semiconductor layer;

a passivation layer disposed on the first conducive semiconductor layer;

a light extracting structure layer on a top surface of the passivation layer and on lateral surfaces of the passivation layer, the light extracting structure layer includes a first material different from a second material of the passivation layer, wherein a concave-convex structure is provided on a top surface of the light extracting structure layer, the top surface of the light extracting structure layer faces away from the passivation layer;

a first electrode layer disposed on the first conductive semiconductor layer, the first electrode layer having a lateral surface, a top surface and a bottom surface;

a second electrode layer disposed under the bottom surface of the support substrate, the second electrode layer including a material forming an interface having an adhesive property and an ohmic contact interface with respect to the support substrate, the second electrode layer being a different structure than the support substrate,

a current spreading layer between the top surface of the support substrate and a bottom surface of the light emitting semiconductor layer,

wherein the passivation layer is disposed on top and lateral surfaces of the light emitting semiconductor layer,

wherein the first electrode layer is disposed on a portion of the first conductive semiconductor layer that is exposed through an open region of the passivation layer,

wherein the passivation layer includes a first portion disposed on the plurality of protrusion parts and a second portion disposed on the lateral surfaces of the light emitting semiconductor layer,

wherein the support substrate is electrically connected to the second conductive semiconductor layer, and

wherein the first electrode layer is electrically connected to the first conductive semiconductor layer,

wherein a width of the second electrode layer is wider than a width of the light emitting semiconductor layer in a horizontal direction,

wherein the first portion of the passivation layer has the open region on the first conductive semiconductor layer, and the first portion of the passivation layer is spaced apart from the first electrode layer,

wherein the bottom surface of the first electrode layer physically contacts the first conductive semiconductor layer at the open region,

wherein a width of the open region is greater than a width of the bottom surface of the first electrode layer,

wherein the lateral surface of the first electrode layer does not physically contact a side surface of the first portion of the passivation layer,

wherein an entire area of the first electrode layer is formed of a metal, and

wherein the first conductive semiconductor layer and the second conductive semiconductor layer includes a nitride-based semiconductor material,

wherein the protrusion parts at a bottom of the passivation layer is disposed spaced apart from the lateral surface of the first electrode layer,

wherein the first material of the light extracting structure layer having a vertical side surface that is aligned with the side surface of the first portion of the passivation layer facing the lateral surface of the first electrode layer and a side surface of the protrusion parts, and

the light emitting device comprising an exposed region of the first conductive semiconductor layer that is disposed at an area between the side surface of the first portion of the passivation layer and the lateral surface of the first electrode layer facing the first portion of the passivation layer.

7. The light emitting device of claim 6, wherein the current spreading layer contacts the second conductive semiconductor layer and includes at least one of Ag, alloy containing Ag, Ni, alloy containing Ni, Al, or alloy containing Al, wherein a surface of the current spreading layer facing the support substrate includes at least one of Ag, Au, Ni, Ti, and Cu.

8. The light emitting device of claim 6, wherein the first conductive semiconductor layer includes an n-type dopant, and the second conductive semiconductor layer includes a p-type dopant, wherein the support substrate includes a metal material and has a thickness in a range of 5 μ

m to 1 mm, wherein the top surface of the first conductive semiconductor layer includes the exposed region that is not overlapped in a vertical direction with the first electrode layer and is not overlapped with the first portion of the passivation layer in the vertical direction.

9. The light emitting device of claim 6, wherein the current spreading layer is formed of Ag material and the support substrate is formed of Si material, wherein a portion of the top surface of the first conductive semiconductor layer is exposed through the open region of the passivation layer.

10. The light emitting device of claim 6, wherein the light extracting structure layer includes one of ZnO, MgZnO, GaN, AlN, TiO₂ and Al₂O₃.