Systems and methods for producing white-light light emitting diodes

• US 7,646,033 B2
• Filed: 03/27/2007
• Issued: 01/12/2010
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Lumens Co., Ltd.
• Original Assignee: SemiLEDs Corporation (SemiLEDs Inc)
• Inventors: Tran, Chuong Anh, Doan, Trung Tri
• Primary Examiner(s): MALSAWMA, LALRINFAMKIM HMAR
• Application Number:
  US11/692,015
• Publication Number:
  US 20070228404A1
• Time in Patent Office: 1,022 Days
• Field of Search: 257/94, 257/E33.012, 257/E33.03, 257/E33.049, 257/E33.061
• US Class Current: 257/94
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/4918 being disposed on at least two different sides of the body, e.g. dual array
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01021 Scandium [Sc]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/641 characterized by the materials

Abstract

A vertical light emitting diode (LED) includes a metal substrate; a p-electrode coupled to the metal substrate; a p-contact coupled to the p-electrode; a p-GaN portion coupled to the p electrode; an active region coupled to the p-GaN portion; an n-GaN portion coupled to the active region; and a phosphor layer coupled to the n-GaN.

Claims

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

a metal substrate deposited adjacent to a p-electrode;

a p-GaN layer disposed above the p-electrode;

an active region for emitting light disposed above the p-GaN layer;

an n-GaN layer disposed above the active region; and

a wafer-level phosphor layer and an n-electrode disposed above the n-GaN layer, wherein the phosphor layer is parallel to the n-GaN layer.

2. The LED structure of claim 1, wherein the metal substrate is deposited using at least one of electrochemical plating, electroless chemical plating, sputtering, chemical vapor deposition, e-beam evaporation, and thermal spray.

3. The LED structure of claim 1, wherein the metal substrate comprises at least one of copper, nickel, aluminum, and alloys thereof.

4. The LED structure of claim 1, further comprising a p-contact interposed between the metal substrate and the p-GaN layer, wherein the p-contact comprises a light reflector.

5. The LED structure of claim 1, wherein the phosphor layer is spin-coated.

6. The LED structure of claim 5, wherein the phosphor layer comprises a phosphor powder composition spin-coated on the n-GaN layer.

7. The LED structure of claim 6, wherein the phosphor powder composition comprises phosphor particles mixed with one or more organic chemicals.

8. The LED structure of claim 1, wherein the phosphor layer is patterned.

9. The LED structure of claim 1, wherein the phosphor layer is dry-etched.

10. The LED structure of claim 1, wherein the n-electrode is a metal bond pad coupled to the n-GaN layer through the phosphor layer.

11. The LED structure of claim 1, wherein the phosphor layer contacts a surface of the n-GaN layer.

12. The LED structure of claim 11, wherein the surface of the n-GaN layer is substantially smooth and planar.

13. The LED structure of claim 1, wherein the thickness of the phosphor layer is substantially uniform.

14. A vertical light-emitting diode (LED) structure, comprising:

a metal substrate deposited adjacent to a p-electrode;

a p-GaN layer disposed above the p-electrode;

an active region for emitting light disposed above the p-GaN layer;

an n-GaN layer disposed above the active region;

a first wafer-level phosphor layer and an n-electrode disposed above the n-GaN layer, wherein the first phosphor layer is parallel to the n-GaN layer; and

a second phosphor layer coupled to the first phosphor layer.

15. The LED structure of claim 14, wherein at least one of the first and the second phosphor layers is patterned.

16. The LED structure of claim 14, wherein the surface of the n-GaN layer is substantially smooth and planar.

17. The LED structure of claim 14, wherein the thickness of the first phosphor layer is substantially uniform.

18. The LED structure of claim 17, wherein the thickness of the second phosphor layer is substantially uniform.

19. LED structure of claim 14, wherein the metal substrate is deposited using at least one of electrochemical plating, electroless chemical plating, sputtering, chemical vapor deposition, e-beam evaporation, and thermal spray.

20. A vertical light-emitting diode (LED) structure, comprising:

a metal substrate deposited adjacent to a p-electrode;

a p-GaN layer disposed above the p-electrode;

an active region for emitting light disposed above the p-GaN layer;

an n-GaN layer disposed above the active region;

a first wafer-level phosphor layer and an n-electrode disposed above the n-GaN layer, wherein the first phosphor layer is parallel to the n-GaN layer; and

a second phosphor layer coupled to the first phosphor layer, wherein the first phosphor layer has a phosphor composition that is photosensitive to a different color than a phosphor composition of the second phosphor layer.