Resonant cavity III-nitride light emitting devices fabricated by growth substrate removal

• US 6,956,246 B1
• Filed: 06/03/2004
• Issued: 10/18/2005
• Est. Priority Date: 06/03/2004
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Krames, Michael R., Epler, John E., Wierer, Jonathan J. Jr.
• Primary Examiner(s): Tran, Thien F.
• Application Number:
  US10/861,745
• Time in Patent Office: 502 Days
• Field of Search: 257/13, 257/79, 257/94, 257/96, 257/98, 257/103, 372/45, 372/46, 372/50
• US Class Current: 257/94
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• 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 33/465 with a resonant cavity structure

Abstract

A semiconductor light emitting device includes an n-type region, a p-type region, and light emitting region disposed between the n- and p-type regions. The n-type, p-type, and light emitting regions form a cavity having a top surface and a bottom surface. Both the top surface and the bottom surface of the cavity may have a rough surface. For example, the surface may have a plurality of peaks separated by a plurality of valleys. In some embodiments, the thickness of the cavity is kept constant by incorporating an etch-stop layer into the device, then thinning the layers of the device by a process that terminates on the etch-stop layer.

Claims

1. A III-nitride light emitting device comprising:

an n-type region;

a p-type region; and

a light emitting region disposed between the n-type region and the p-type region;

wherein the n-type region, p-type region, and light emitting region form a cavity, the cavity having a top surface and a bottom surface, wherein each of the top surface and the bottom surface comprise a plurality of peaks separated by a plurality of valleys.

2. The device of claim 1 wherein a distance between a bottom of a valley and a top of a peak is between 15 nm and 100 nm.

3. The device of claim 1 wherein a distance between two nearest neighbor valleys is less than 100 microns.

4. The device of claim 1 wherein a thickness of the cavity at any point in the cavity varies less than λ

/8, where λ

is a wavelength, in the cavity, of light emitted by the light emitting region.

5. The device of claim 1 further comprising:

a first mirror disposed proximate to the n-type region; and

a second mirror disposed proximate to the p-type region.

6. The device of claim 5 wherein the first mirror comprises a dielectric distributed Bragg reflector.

7. The device of claim 5 wherein the second mirror comprises a reflective metal layer.

8. The device of claim 7 wherein the second mirror comprises silver.

9. The device of claim 5 wherein the second mirror comprises a dielectric distributed Bragg reflector.

10. The device of claim 5 wherein the first mirror is divided into a plurality of regions and the regions are separated from each other by a first contact.

11. The device of claim 10 wherein:

the second mirror is divided into a plurality of regions and the regions are separated from each other by a second contact; and

the plurality of first mirror regions are aligned with the plurality of second mirror regions.

12. The device of claim 11 wherein a portion of the n-type region between the first contact and the second contact is implanted with hydrogen.

13. The device of claim 10 wherein each region in the plurality of regions has a length between about 50 microns and about 150 microns.

14. The device of claim 10 wherein a width of the first contact separating the regions is between about 1 micron and about 10 microns.

15. The device of claim 5 where at least a portion of the first mirror overlies at least a portion of the second mirror.

16. The device of claim 5 further comprising a layer of conductive material disposed between the n-type region and the first mirror.

17. The device of claim 16 wherein the conductive material comprises indium tin oxide.

18. The device of claim 1 wherein the thickness of material between the top surface and the bottom surface is less than three microns.

19. The device of claim 1 wherein the thickness of material between the top surface and the bottom surface is less than one micron.

20. The device of claim 1 wherein the thickness of material between the top surface and the bottom surface is less than half a micron.

21. The device of claim 1 further comprising a plurality of etch vias formed in the n-type region.

22. The device of claim 21 wherein the etch vias are spaced between about 0.1 micron and about 2 microns apart.

23. The device of claim 21 wherein the etch vias each have a depth between about 0.1 micron and about 2.5 microns.

24. The device of claim 1 wherein the top surface and the bottom surface form a resonant cavity and an electric field intensity in the cavity forms a standing wave.

25. The device of claim 24 wherein at least a portion of the light emitting region is located near a maximum in the electric field intensity.