LEDs with efficient electrode structures

• US 9,356,194 B2
• Filed: 04/22/2015
• Issued: 05/31/2016
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: Shum, Frank T., So, William W., Lester, Steven D.
• Primary Examiner(s): Nguyen, Dao H
• Application Number:
  US14/693,667
• Publication Number:
  US 20150228860A1
• Time in Patent Office: 405 Days
• Field of Search: 257/76, 257/79, 257/80, 257/96, 257/98, 257/99, 257/E33.005, 257/E33.061, 257/E33.067, 257/E33.068, 257/E27.121, 257/E21.002, 372/38.09, 372/43.01, 372/50.124, 438/29, 438/31, 438/32
• US Class Current: 1/1
• 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 33/24 of the light emitting region, e.g. non-planar junction
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/385 the electrode extending at least partially onto a side surface of the semiconductor body
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/42 Transparent 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 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Aspects include Light Emitting Diodes that have a GaN-based light emitting region and a metallic electrode. The metallic electrode can be physically separated from the GaN-based light emitted region by a layer of porous dielectric, which provides a reflecting region between at least a portion of the metallic electrode and the GaN-based light emitting region.

Claims

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

a semiconductor comprising an active region arranged with a doped region having a surface through which light generated in the active region can be emitted;

a reflective dielectric on the surface; and

an electrode comprising a first portion on the dielectric such that the dielectric is disposed between the doped region and the first portion of the electrode, and a second portion electrically coupled to the surface.

2. The LED of claim 1, wherein a material of the dielectric is porous.

3. The LED of claim 1, wherein a material of the dielectric comprises porous indium tin oxide (ITO).

4. The LED of claim 1, wherein the first portion of the electrode on the dielectric extends substantially across at least one axis of direction of the dielectric.

5. The LED of claim 1, wherein the semiconductor comprises Gallium Nitride (GaN).

6. The LED of claim 1, wherein the semiconductor is formed on a substrate comprised of sapphire.

7. The LED of claim 1, further comprising an ohmic layer disposed between the surface on one hand, and the dielectric and the electrode on the other hand.

8. The LED of claim 1, further comprising:

a second doped region having a surface substantially parallel with the surface of the doped region, the second doped region in electrical contact with the active region;

a second reflective dielectric on the surface of the second doped region; and

a second electrode formed partially on the second dielectric and partially on the surface of the second doped region such that the second dielectric is disposed between the second doped region and the second electrode formed partially on the second dielectric.

9. The LED of claim 8, wherein the surfaces of the doped region and the second doped region are the same.

10. The LED of claim 8, wherein the surface of the second doped region is different from the surface of the doped region, the surface of the second doped region being a cutout of at least the doped region.

11. An electrode structure for a light-emitting diode (LED), comprising:

a semiconductor comprising a doped region having a surface;

a dielectric formed on the surface, the dielectric for reflecting light emitted from an active region of the semiconductor; and

a metal bond pad formed partially on the dielectric and partially on the surface such that the dielectric is disposed between the doped region and the metal bond pad formed partially on the dielectric.

12. The electrode structure of claim 11, wherein a material of the dielectric is porous.

13. The electrode structure of claim 11, wherein a material of the dielectric comprises porous indium tin oxide (ITO).

14. The electrode structure of claim 11, wherein a portion of the metal bond pad formed on the dielectric extends substantially across at least one axis of direction of the dielectric.

15. The electrode structure of claim 11, wherein the semiconductor comprises Gallium Nitride (GaN).

16. The electrode structure of claim 11, wherein the semiconductor is formed on a substrate comprised of sapphire.

17. The electrode structure of claim 11, further comprising an ohmic layer disposed between the surface on one hand, and the dielectric and the metal bond pad on the other hand.