Monolitholic LED chip to emit multiple colors

• US 7,271,420 B2
• Filed: 07/07/2005
• Issued: 09/18/2007
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: CAO Group, Inc.
• Inventors: Cao, Densen
• Primary Examiner(s): CRANE, SARA W
• Application Number:
  US11/176,696
• Publication Number:
  US 20060027820A1
• Time in Patent Office: 803 Days
• Field of Search: 257/89, 257/90, 257/88, 257/91, 257/94, 257/96, 257/97, 257/99
• US Class Current: 257/89
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body

Abstract

A light emitting diode chip with red, green and blue light emission regions on a single substrate. The light emission regions may be powered selectively to only emit one color light at a time. Or all three regions may be powered simultaneously so that the LED chip emits white light.

Claims

1. A light emitting diode chip comprising:

a substrate,

a buffer layer on one side of the substrate to reduce lattice mismatch defects between the substrate and an epitaxial layer,

a first color emission region layered on top of the buffer layer,

said first color emission region including

a first color emission lower dielectric layer,

a first color emission lower contact layer for establishing electrical contact,

a first color emission underside cladding layer, a first color emission active layer capable of emitting light, a first color emission topside cladding layer,

a first color emission upper contact layer for establishing electrical contact,

a first color emission upper dielectric layer,

a second color emission region layered on top of the first color emission region,

a second color emission lower dielectric layer,

a second color emission lower contact layer for establishing electrical contact,

a second color emission underside cladding layer, a second color emission active layer capable of emitting light,

a second color emission topside cladding layer,

a second color emission upper contact layer for establishing electrical contact,

a second color emission upper dielectric layer,

a third color emission region layered on top of the second color emission region,

a third color emission lower dielectric layer,

a third color emission lower contact layer for establishing electrical contact,

a third color emission underside cladding layer,

a third color emission active layer capable of emitting light,

a third color emission topside cladding layer,

a third color emission upper contact layer for establishing electrical contact,

a third color emission upper dielectric layer,

a topside of the LED chip, said topside being on another side of the chip from said substrate,

a first color emission lower contact layer electrical connection structure including

a first color emission electrical connection lower contact layer contact hole etched from said topside to said first color emission lower contact layer,

a first color emission electrical connection lower contact layer insulation layer located inside of said a first color emission electrical connection lower contact layer contact hole,

a first color emission electrical connection lower contact layer conductive metal located inside of said first color emission electrical connection lower contact layer contact hole and running from said topside to said first color emission lower contact layer,

a first color emission electrical connection lower contact layer electrode located topside of the LED chip and being in electrical contact with said first color emission electrical connection lower contact layer conductive metal located inside of said first color emission electrical connection lower contact layer contact hole,

a first color emission upper contact layer electrical connection structure including

a first color emission electrical connection upper contact layer contact hole etched from said topside to said first color emission upper contact layer,

a first color emission electrical connection upper contact layer insulation layer located inside of said a first color emission electrical connection upper contact layer contact hole,

a first color emission electrical connection upper contact layer conductive metal located inside of said first color emission electrical connection upper contact layer contact hole and running from said topside to said first color emission upper contact layer,

a first color emission electrical connection upper contact layer electrode located topside of the LED chip and being in electrical contact with said first color emission electrical connection upper contact layer conductive metal located inside of said first color emission electrical connection upper contact layer contact hole,

a second color emission lower contact layer electrical connection structure including

a second color emission electrical connection lower contact layer contact hole etched from said topside to said second color emission lower contact layer,

a second color emission electrical connection lower contact layer insulation layer located inside of said a second color emission electrical connection lower contact layer contact hole,

a second color emission electrical connection lower contact layer conductive metal located inside of said second color emission electrical connection lower contact layer contact hole and running from said topside to said second color emission lower contact layer,

a second color emission electrical connection lower contact layer electrode located topside of the LED chip and being in electrical contact with said second color emission electrical connection lower contact layer conductive metal located inside of said second color emission electrical connection lower contact layer contact hole,

a second color emission upper contact layer electrical connection structure including

a second color emission electrical connection upper contact layer contact hole etched from said topside to said second color emission upper contact layer,

second color emission electrical connection upper contact layer insulation layer located inside of said a second color emission electrical connection upper contact layer contact hole,

a second color emission electrical connection upper contact layer conductive metal located inside of said second color emission electrical connection upper contact layer contact hole and running from said topside to said second color emission upper contact layer,

a second color emission electrical connection upper contact layer electrode located topside of the LED chip and being in electrical contact with said second color emission electrical connection upper contact layer conductive metal located inside of said second color emission electrical connection upper contact layer contact hole,

a third color emission lower contact layer electrical connection structure including

a third color emission electrical connection lower contact layer contact hole etched from said topside to said third color emission lower contact layer,

a third color emission electrical connection lower contact layer insulation layer located inside of said a third color emission electrical connection lower contact layer contact hole,

a third color emission electrical connection lower contact layer conductive metal located inside of said third color emission electrical connection lower contact layer contact hole and running from said topside to said third color emission lower contact layer,

a third color emission electrical connection lower contact layer electrode located topside of the LED chip and being in electrical contact with said third color emission electrical connection lower contact layer conductive metal located inside of said third color emission electrical connection lower contact layer contact hole,

a third color emission upper contact layer electrical connection structure including

a third color emission electrical connection upper contact layer contact hole etched from said topside to said third color emission upper contact layer,

a third color emission electrical connection upper contact layer insulation layer located inside of said a third color emission electrical connection upper contact layer contact hole,

a third color emission electrical connection upper contact layer conductive metal located inside of said third color emission electrical connection upper contact layer contact hole and running from said topside to said third color emission upper contact layer,

a third color emission electrical connection upper contact layer electrode located topside of the LED chip and being in electrical contact with said third color emission electrical connection upper contact layer conductive metal located inside of said third color emission electrical connection upper contact layer contact hole.

2. A light emitting diode chip as recited in claim 1 wherein said first color emission region emits red light when powered.

3. A light emitting diode chip as recited in claim 1 wherein said second color emission region emits green light when powered.

4. A light emitting diode chip as recited in claim 1 wherein said third color emission emits blue light when powered.

5. A light emitting diode chip as recited in claim 1 wherein said first, second and third color emission regions emit light selected from the group of colors consisting of red, blue and green.

6. A light emitting diode chip as recited in claim 1 wherein said first, second and third regions emit red, green and blue light, respectively.

7. A light emitting diode chip as recited in claim 1 wherein one of said first, second and third regions emits red light, another emits green light, and another emits blue light.

8. A light emitting diode chip as recited in claim 1 wherein powering all three of said color emission regions results in the emission of white light from the LED chip.

9. A light emitting diode chip as recited in claim 1 wherein each of said first, second and third color emission regions emits a different color of light from the other of said regions.

10. A light emitting diode chip as recited in claim 1 wherein each of said first, second and third color emission regions may be selectively powered so that only one region emits light, or more than one region emits light, or all 3 regions emit light simultaneously.

11. A light emitting diode chip as recited in claim 1 wherein said substrate is selected from the group consisting of Si, GaAs, GaN, AlN, SiC, and Sapphire.

12. A light emitting diode chip as recited in claim 1 wherein at least one of said active layers includes a material selected from the group consisting of GaInP, AlGaInP, GaInN, or GaNP.

13. A light emitting diode chip comprising:

a substrate,

a first color emission region layered on top of the substrate and having a first color emission active layer capable of emitting light when powered,

a second color emission region layered on top of the first color emission region and having a second color emission active layer capable of emitting light when powered,

a third color emission region layered on top of the second color emission region and having a third color emission active layer capable of emitting light when powered,

each color emission region further comprising;

at least one active layer having both an upper and a lower face, at least one cladding layer proximate each of the upper and a lower faces of the active layer such that two cladding layer outer faces are defined opposite the upper and lower faces, and at least one electrical contact layer proximate both of the cladding layer outer faces;

at least one dielectric layer being positioned between color emission regions and between the first color emission region and the substrate;

a topside of the LED chip, said topside being on another side of the chip from said substrate,

a first color emission region electrical connection structure etched from said topside to said first color emission region in order to power said first color emission region and cause it to emit light of a first color,

a second color emission region electrical connection structure etched from said topside to said second color emission region in order to power said second color emission region and cause it to emit light of a second color,

a third color emission region electrical connection structure etched from said topside to said third color emission region in order to power said third color emission region and cause it to emit light of a third color;

each connection structure further comprising two insulated electrical connection leads, one contacting an upper contact layer of the specific color emission region and the other contacting a lower contact layer, each lead attached to an electrical contact layer and extending through a hole etched down to a specific contact layer from a top layer, the insulated connection leads only contacting the specific contact layer,

wherein said first, second and third colors of light each represent a different wavelength of light.

14. A light emitting diode chip as recited in claim 13 wherein one of said first, second and third regions emits red light, another emits green light, and another emits blue light.

15. A light emitting diode chip as recited in claim 13 wherein powering all three of said color emission regions results in the emission of white light from the LED chip.

16. A light emitting diode chip as recited in claim 13 wherein said first, second and third regions may be selectively powered to emit light from one region, from two regions, or from all 3 regions simultaneously.