SINGLE OR MULTI-COLOR HIGH EFFICIENCY LIGHT EMITTING DIODE (LED) BY GROWTH OVER A PATTERNED SUBSTRATE

• US 20080087909A1
• Filed: 10/24/2007
• Published: 04/17/2008
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: David, Aurelien, DenBaars, Steven, Speck, James, Weisbuch, Claude
• Granted Patent: US 7,755,096 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• 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 33/20 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 33/24 of the light emitting region, e.g. non-planar junction

Abstract

A single or multi-color light emitting diode (LED) with high extraction efficiency is comprised of a substrate, a buffer layer formed on the substrate, one or more patterned layers deposited on top of the buffer layer, and one or more active layers formed on or between the patterned layers, for example by Lateral Epitaxial Overgrowth (LEO), and including one or more light emitting species, such as quantum wells. The patterned layers include a patterned, perforated or pierced mask made of insulating, semiconducting or metallic material, and materials filling holes in the mask. The patterned layer acts as an optical confining layer due to a contrast of a refractive index with the active layer and/or as a buried diffraction grating due to variation of a refractive index between the mask and the material filling the holes in the mask.

Claims

1. An optoelectronic device, comprising:

(a) one or more patterned layers, wherein each patterned layer comprises a mask and materials filling holes in the mask; and

(b) one or more III-nitride layers formed on or between the patterned layers, wherein the III-nitride layers include one or more light emitting species.

2. The device of claim 1, wherein the patterned layer acts as an optical confining layer for the light emitting species of the III-nitride layers due to a contrast of a refractive index with the III-nitride layers.

3. The device of claim 1, wherein the patterned layer acts as a buried diffraction grating for the light emitting species of the III-nitride layers due to variations of a refractive index between the mask and the materials filling holes in the mask.

4. The device of claim 1, wherein the mask is comprised of an insulating, semiconducting or metallic material.

5. The device of claim 1, where the materials filling the holes in the mask comprise III-nitride materials.

6. The device of claim 1, further comprising mirrors placed above or below the patterned layer, to enhance or decrease emissions in a desired direction.

7. The device of claim 1, wherein different patterns in the patterned layer are used to extract different wavelengths by diffraction or to vary a direction of the diffraction.

8. The device of claim 1, wherein additional optically-pumped active regions are used to recycle the guided modes, thus re-emitting a portion of guided modes at another frequency.

9. A method of fabricating an optoelectronic device, comprising:

(a) forming one or more patterned layers, wherein each patterned layer comprises a mask and materials filling holes in the mask; and

(b) forming one or more III-nitride layers on or between the patterned layers, wherein the III-nitride layers include one or more light emitting species.

10. The method of claim 9, wherein the patterned layer acts as an optical confining layer for the light emitting species of the III-nitride layers due to a contrast of a refractive index with the III-nitride layers.

11. The method of claim 9, wherein the patterned layer acts as a buried diffraction grating for the light emitting species of the III-nitride layers due to variations of a refractive index between the mask and the materials filling holes in the mask.

12. The method of claim 9, wherein the mask is comprised of an insulating, semiconducting or metallic material.

13. The method of claim 9, where the materials filling the holes in the mask comprise III-nitride materials.

14. The method of claim 9, further comprising mirrors placed above or below the patterned layer, to enhance or decrease emissions in a desired direction.

15. The method of claim 9, wherein different patterns in the patterned layer are used to extract different wavelengths by diffraction or to vary a direction of the diffraction.

16. The method of claim 9, wherein additional optically-pumped active regions are used to recycle the guided modes, thus re-emitting a portion of guided modes at another frequency.

17. A device fabricated using the method of claim 9.