Power light emitting diode and method with uniform current density operation

• US 9,293,644 B2
• Filed: 09/27/2013
• Issued: 03/22/2016
• Est. Priority Date: 09/18/2009
• Status: Active Grant

• Current Assignee: Korrus Incorporated (MKD Electric, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: Katona, Thomas M., Raring, James W., D'Evelyn, Mark P., Krames, Michael R., David, Aurelien J. F.
• Primary Examiner(s): VU, JIMMY T
• Application Number:
  US14/040,379
• Publication Number:
  US 20140027789A1
• Time in Patent Office: 907 Days
• Field of Search: 257/79, 257/98, 257/E33, 315/291
• US Class Current: 1/1
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H05B 45/00 Circuit arrangements for operating light-emitting diodes [LED]

Abstract

A light emitting diode device has a bulk gallium and nitrogen containing substrate with an active region. The device has a lateral dimension and a thick vertical dimension such that the geometric aspect ratio forms a volumetric diode that delivers a nearly uniform current density across the range of the lateral dimension.

Claims

1. A light emitting diode comprising:

a bulk gallium and nitrogen containing substrate having a surface region; and

an active region formed overlying the surface region;

wherein, the light emitting diode is configured to emit light from the active region having an emission intensity varying no more than +/−

20% across the active region, at a current density between 175 Amps/cm² and 2,000 Amps/cm².

2. The light emitting diode of claim 1, wherein the emission intensity across the active region is within +/−

10% at a current density from 175 Amps/cm² to 2,000 Amps/cm².

3. The light emitting diode of claim 1, wherein the active region is characterized by a characteristic lateral dimension of at least 100 μ

m.

4. The light emitting diode of claim 1, wherein the light emitting diode is characterized by a vertical dimension and a characteristic lateral dimension, wherein a ratio of the vertical dimension to the characteristic lateral dimension is from 0.05 to 10.

5. The light emitting diode of claim 1, wherein the aspect ratio of the thickness to the longest lateral side is from 0.1 to 5.

6. The light emitting diode of claim 5, wherein the ratio is from 0.2 to 2.

7. The light emitting diode of claim 1, wherein the light emitting diode is characterized by an aspect ratio defined by the ration of the vertical dimension and a characteristic lateral dimension of the surface region, wherein the aspect ratio is selected to provide a substantially uniform current density across the characteristic lateral dimension of the surface region.

8. The light emitting diode of claim 1, wherein the light emitting diode is configured to emit at wavelengths from 405 nm to 430 nm.

9. The light emitting diode of claim 1, wherein active region is characterized by a thickness from 0.5 nm to 40 nm.

10. The light emitting diode of claim 1, wherein the active region is characterized by a thickness is from 40 nm to 500 nm.

11. The light emitting diode of claim 1, wherein the bulk gallium and nitrogen containing substrate is n-doped and is characterized by a resistivity less than 0.5 Ohm-cm.

12. The light emitting diode of claim 1, wherein the bulk gallium and nitrogen containing substrate is p-doped and is characterized by a resistivity less than 0.05 Ohm-cm.

13. The light emitting diode of claim 1, further comprising a junction area from about 0.0002 mm² to about 1 mm².

14. The light emitting diode of claim 1, wherein the active region is characterized by a junction temperature greater than about 100 degrees Celsius.

15. The light emitting diode of claim 1, wherein the bulk gallium and nitrogen containing substrate is characterized by a resistivity less than about 0.050 Ohm-cm.

16. The light emitting diode of claim 1, wherein the current density is from 400 Amps/cm² to 800 Amps/cm², at emission wavelengths from 405 nm to 430 nm.

17. The light emitting diode of claim 1, wherein the current density is from 200 Amps/cm² to 1,000 Amps/cm², at emission wavelengths from 405 nm to 430 nm.

18. The light emitting diode of claim 1, wherein the current density is from 500 Amps/cm² to 1,000 Amps/cm², at emission wavelengths from 405 nm to 430 nm.

19. The light emitting diode of claim 1, wherein the current density is from 1,000 Amps/cm² to 2,000 Amps/cm², at emission wavelengths from 405 nm to 430 nm.

20. The light emitting diode of claim 1, wherein the light emitting diode is characterized by a lumens per active junction area of greater than 300 lm/mm², for a warm white emission with a correlated color temperature (CCT) of less than about 5,000K, and a color rendering index (CRI) greater than 75.

21. A lighting fixture comprising the light emitting diode of claim 1.

22. A lamp comprising the light emitting diode of claim 1.

23. The lamp of claim 22, wherein the lamp is a replacement lamp.

24. The lamp of claim 22, wherein the lamp conforms to a form factor selected from an A-lamp, a fluorescent tube, a compact fluorescent lamp (CFL), a metallic reflector (MR) lamp, an MR16 lamp, a parabolic reflector (PAR) lamp, a reflector bulb (R), a single end quartz halogen lamp, a double end quartz halogen lamp, a candelabra, a globe bulb, a high bay lamp, a troffer lamp, and a cobra head lamp.

25. A light emitting diode comprising:

a bulk gallium and nitrogen containing substrate having a surface region bounded by a polygonal area formed of at least a longest lateral side and a shortest lateral side; and

an active region formed by epitaxial growth upon the surface region;

the light-emitting diode having a thickness wherein the aspect ratio of the thickness to the longest lateral side is from about 0.05 to about 10, and being configured to emit light from the active region having an emission intensity varying no more than +/−

20% across the active region

at a current density of greater than about 175 Amps/cm².

26. The light emitting diode of claim 25, wherein the aspect ratio of the thickness to the longest lateral side is from about 0.2 to about 2.

27. A lighting fixture comprising the light emitting diode of claim 25.

28. A lamp comprising the light emitting diode of claim 25.

29. The lamp of claim 28, wherein the lamp is a replacement lamp.

30. The lamp of claim 28, wherein the lamp conforms to a form factor selected from an A-lamp, a fluorescent tube, a compact fluorescent lamp (CFL), a metallic reflector (MR) lamp, an MR16 lamp, a parabolic reflector (PAR) lamp, a reflector bulb (R), a single end quartz halogen lamp, a double end quartz halogen lamp, a candelabra, a globe bulb, a high bay lamp, a troffer lamp, and a cobra head lamp.