LEDs with efficient electrode structures

• US 10,199,543 B2
• Filed: 03/09/2017
• Issued: 02/05/2019
• 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:
  US15/454,600
• Publication Number:
  US 20170317239A1
• Time in Patent Office: 698 Days
• Field of Search: 257 79, 257 80, 257 96, 257 98, 257 99, 257E33005, 257E33061, 257E33067, 257E33068, 257E27121, 257E21002, 372 3809, 372 4301, 372 50124, 438 29, 438 31, 438 32
• 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) device, comprising:

a Gallium-Nitride (GaN) based semiconductor structure comprising an active region that is in electrical contact with a P doped region having a surface configured such that light generated in the active region can be emitted;

a metallic electrode structure comprising a bonding pad area, with the metallic electrode structure in electrical contact with the surface of the P-doped region; and

a non-perforated and porous dielectric material interposed between the planar surface of the P-doped region and the bonding pad area.

2. The Light Emitting Diode (LED) device of claim 1, wherein the non-perforated and porous dielectric material is disposed at a physical interface between the bonding pad area and the surface of the P-doped region and defines a region of total internal reflection between the metallic electrode structure and the GaN based semiconductor structure.

3. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 90% of light incident at angles between zero degrees and thirteen degrees.

4. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 92% of light incident at angles between zero degrees and ten degrees.

5. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 82% of light incident at angles between twenty-two degrees and twenty-seven degrees.

6. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 85% of light incident at angles between twenty-three degrees and twenty-six degrees.

7. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 85% of light incident for a total angular range of at least 20 degrees within a range of zero to forty degrees.

8. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 85% of light incident within a total of at least 22 degrees within a range of incident angles between zero and forty degrees.

9. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface of the region of total internal reflection is configured to reflect at least 90% of light incident within a total of at least 16 degrees for a range of incident angles between zero and forty degrees.

10. The Light Emitting Diode (LED) device of claim 2, wherein the physical interface between the bonding pad area and the surface further comprises a current spreading layer.

11. An electrode for a Light Emitting Diode (LED) semiconductor device, the electrode structure comprising:

a metallic structure in electrical contact with a surface of a P-doped region of a semiconductor, and comprising a bonding pad area; and

a porous layer of dielectric material physically disposed between the bonding pad area and the surface of the P-doped region,

wherein the porous layer of dielectric material forms a physical interface comprising a reflective region configured to reflect at least 85% of light incident at angles between zero degrees and fifteen degrees.

12. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the reflective region is configured to reflect at least 90% of light incident at angles between zero degrees and thirteen degrees.

13. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the porous layer of dielectric material is nano-porous Silicon Dioxide.

14. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the reflective region is configured to reflect at least 92% of light incident at angles between zero degrees and ten degrees.

15. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the reflective region is configured to reflect at least 82% of light incident at angles between twenty-two degrees and twenty-seven degrees.

16. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the reflective region configured to reflect at least 85% of light incident at angles between twenty-three degrees and twenty-six degrees.

17. The electrode for a Light Emitting Diode (LED) device of claim 11, wherein the reflective region is configured to reflect at least 85% of light incident within a total of at least 20 degrees for a range of incident angles between zero and forty degrees.