Light emitting diode having vertical topology and method of making the same

• US 9,530,936 B2
• Filed: 12/04/2013
• Issued: 12/27/2016
• Est. Priority Date: 06/23/2006
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation), LG Innotek Company Limited (LG Corporation)
• Inventors: Jang, Jun Ho, Choi, Jae Wan, Bae, Duk Kyu, Cho, Hyun Kyong, Park, Jong Kook, Kim, Sun Jung, Lee, Jeong Soo
• Primary Examiner(s): Landau, Matthew
• Assistant Examiner(s): STOWE, SCOTT C
• Application Number:
  US14/097,028
• Publication Number:
  US 20140091277A1
• Time in Patent Office: 1,119 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/40 Materials therefor
• 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

Abstract

An LED having vertical topology and a method of making the same is capable of improving a luminous efficiency and reliability, and is also capable of achieving mass productivity. The method includes forming a semiconductor layer on a substrate; forming a first electrode on the semiconductor layer; forming a supporting layer on the first electrode; generating an acoustic stress wave at the interface between the substrate and semiconductor layer, thereby separating the substrate from the semiconductor layer; and forming a second electrode on the semiconductor layer exposed by the separation of the substrate.

Claims

1. A light emitting device, comprising:

a supporting layer;

a semiconductor structure on the supporting layer, the semiconductor structure comprising a first surface, a second surface opposite the first surface, and an inclined side surface with reference to the first surface;

a light-extraction structure that is part of the second surface of the semiconductor structure;

a passivation layer around the semiconductor structure;

a connection metal layer between the supporting layer and the first surface of the semiconductor structure and between the supporting layer and the passivation layer, a width of the connection metal layer in a width direction perpendicular to a thickness direction of the supporting layer being wider than a width of the light-extraction structure in the width direction;

a first electrode between the connection metal layer and the first surface of the semiconductor structure, wherein the first electrode comprises;

a reflective electrode; and

an ohmic electrode on the reflective electrode; and

a second electrode on the second surface of the semiconductor structure.

2. The device according to claim 1, wherein the width of the connection metal layer in the width direction comprises:

a first width of a first part of the connection metal layer between the supporting layer and the first surface of the semiconductor structure; and

a second width of a second part of the connection metal layer disposed between the supporting layer and the passivation layer, the second part being adjacent to the first part of the connection metal layer.

3. The device according to claim 1, wherein the connection metal layer comprises at least one of Cu, Au, Sn, In, Ag, an alloy of any combination thereof, and a stack of any combination thereof.

4. The device according to claim 1, wherein the connection metal layer comprises:

a first layer;

a diffusion barrier layer on the first layer; and

a second layer on the diffusion barrier layer.

5. The device according to claim 4, wherein the first layer comprises an Au layer or a Cu layer.

6. The device according to claim 4, wherein the diffusion barrier layer comprises at least one of Ni, W, Ti, and Pt.

7. The device according to claim 4, wherein the second layer comprises at least one of Ni, W, Ti, Pt, Au, Pd, Cu, Al, Cr, Ag, and an alloy of any combination thereof.

8. The device according to claim 1, wherein the light-extraction structure comprises irregularities on a surface of the semiconductor structure.

9. The device according to claim 1, wherein the passivation layer comprises at least one of SiO₂, SiN, epoxy-based photoresist, acrylic-based photoresist, SOG, and polyimide.

10. The device according to claim 1, wherein the passivation layer comprises at least two layers, the passivation layer comprising:

a first passivation layer; and

a second passivation layer on the first passivation layer.

11. The device according to claim 1, wherein the reflective electrode comprises at least one of Ag or Al.

12. The device according to claim 1, wherein the thickness of the reflective electrode is in a range of about 10 nm to 500 nm.

13. The device according to claim 1, wherein the thickness of the reflective electrode is more than 500 nm.

14. The device according to claim 1, wherein the connection metal layer has a multi-layer structure.

15. The device according to claim 1, wherein the connection metal layer is a reflective layer.

16. The device according to claim 1, wherein the connection metal layer is a bonding layer for attaching the supporting layer.

17. The device according to claim 1, wherein the supporting layer comprises a semiconductor layer.

18. The device according to claim 1, wherein the semiconductor structure comprises:

a p-type semiconductor layer;

an active layer on the p-type semiconductor layer; and

an n-type semiconductor layer on the active layer.

19. The device according to claim 1, where the connection metal layer includes a step-down portion on a fringe of the first surface of the semiconductor structure, the step-down portion being filled with the passivation layer that extends to the semiconductor layer therefrom to protect the inclined side surface of the semiconductor structure.

20. The device according to claim 1, wherein a width of the first electrode in the width direction is smaller than the width of the connection metal layer.