Vertical light emitting diodes (LED) having metal substrate and spin coated phosphor layer for producing white light

• US 8,680,534 B2
• Filed: 09/07/2011
• Issued: 03/25/2014
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: SemiLEDs Corporation (SemiLEDs Inc)
• Original Assignee: SemiLEDs Corporation (SemiLEDs Inc)
• Inventors: Tran, Chuong A, Doan, Trung Tri
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): Harrison, Monica D
• Application Number:
  US13/227,335
• Publication Number:
  US 20120032184A1
• Time in Patent Office: 930 Days
• Field of Search: 257/76, 257/98, 257/E33.023, 257 89- 96
• US Class Current: 257/76
• 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 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• 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 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• 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 (VLED) 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 portion.

Claims

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

metal substrate;

a p-GaN layer on the metal substrate;

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

an N-GaN layer on the active region; and

a spin coated phosphor layer on the n-GaN layer configured to change a wavelength of the light emitted by the active region to produce a white light, the spin coated phosphor layer comprising a phosphor powder and an organic chemical having a pre-cured viscosity selected to provide a predetermined thickness and color coordination for the white light.

2. The vertical light-emitting diode (LED) of claim 1 wherein the metal substrate comprises a deposited layer.

3. The vertical light-emitting diode (LED) of claim 1 wherein the metal substrate comprises an element selected from the group consisting of Ag, Al, TiW, W, Mo, Ta, and TaN.

4. The vertical light-emitting diode (LED) of claim 1 further comprising a p-contact configured as a light reflector between the metal substrate and the p-GaN layer.

5. The vertical light-emitting diode (LED) of claim 1 wherein the spin coated phosphor layer comprises a patterned layer.

6. The vertical light-emitting diode (LED) of claim 1 wherein the spin coated phosphor layer comprises a dry-etched layer.

7. The vertical light-emitting diode (LED) of claim 1 further comprising a metal bond pad coupled to the n-GaN layer through the spin coated phosphor layer.

8. The vertical light-emitting diode (LED) of claim 1 wherein the spin coated phosphor layer contacts a surface of the n-GaN layer.

9. The vertical light-emitting diode (LED) of claim 1 wherein a surface of the n-GaN layer comprises a substantially smooth and planar surface.

10. A vertical light-emitting diode (LED) comprising:

a metal substrate;

a p-GaN layer on the metal substrate;

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

an n-GaN layer on the active region;

a first spin coated phosphor layer on the n-GaN layer; and

a second spin coated phosphor layer on the first phosphor layer,

the first spin coated phosphor layer and the second spin coated phosphor layer configured to change a wavelength of the light emitted by the active region to produce a white light, the first spin coated phosphor layer and the second spin coated phosphor layer comprising a phosphor powder and an organic chemical having a pre-cured viscosity selected to provide predetermined thicknesses and a predetermined color coordination for the white light.

11. The vertical light-emitting diode (LED) of claim 10 wherein the first phosphor layer and the second phosphor layer comprise patterned layers.

12. The vertical light-emitting diode (LED) of claim 10 wherein a surface of the n-GaN layer comprises a substantially smooth and planar surface.