Non-polar and semi-polar light emitting devices

• US 20080179607A1
• Filed: 12/11/2007
• Published: 07/31/2008
• Est. Priority Date: 12/11/2006
• Status: Active Grant

• Current Assignee: Japan Science & Technology Trading Co. Limited
• Original Assignee: Japan Science & Technology Trading Co. Limited, Regents of the University of California (University of California)
• Inventors: Speck, James S., DenBaars, Steven P., Kim, Kwang Choong, Nakamura, Shuji, Schmidt, Mathew C.
• Granted Patent: US 9,130,119 B2
• Time in Patent Office: Days
• US Class Current: 257/94
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/3404 influencing the polarisation
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

An (Al, Ga, In)N light emitting device, such as a light emitting diode (LED), in which high light generation efficiency is realized by fabricating the device on non-polar or semi-polar III-Nitride crystal geometries. Because non-polar and semi-polar emitting devices have significantly lower piezoelectric effects than c-plane emitting devices, higher efficiency emitting devices at higher current densities can be realized.

Claims

1. A non-polar or semi-polar III-nitride light emitting device, comprising:

a plurality of non-polar or semi-polar III-nitride layers comprising one or more p-type layers, an active region, and one or more n-type layers, wherein the active region includes one or more quantum wells having a thickness greater than 4 nanometers.

2. The device of claim 1, wherein the quantum wells have a thickness of approximately 8-12 nanometers.

3. The device of claim 1, wherein the quantum wells have a thickness of approximately 10 nanometers.

4. The device of claim 1, wherein the non-polar III-nitride layers comprise m-plane or a-plane III-nitride layers.

5. The device of claim 1, wherein one or more emitting surfaces of the device is roughened, textured, patterned or shaped.

6. The device of claim 5, wherein more than one emitting surface of the device is roughened, textured, patterned or shaped.

7. The device of claim 5, wherein the emitting surface of the device is a cone shaped surface.

8. The device of claim 1, wherein the active region is comprised of multiple emitting layers emitting light at more than one wavelength.

9. The device of claim 1, further comprising a transparent electrode layer is formed adjacent the non-polar or semi-polar III-nitride layers.

10. The device of claim 9, wherein the transparent electrode layer is an electrically conductive contact layer.

11. The device of claim 9, wherein a surface of the transparent layer is roughened, textured, patterned or shaped.

12. The device of claim 9, wherein a current spreading layer is deposited before the transparent electrode layer.

13. The device of claim 1, wherein the device is placed on a transparent mounting structure.

14. A method of fabricating a non-polar or semi-polar III-nitride light emitting device, comprising:

forming a plurality of non-polar or semi-polar III-nitride layers comprising one or more p-type layers, an active region, and one or more n-type layers, wherein the active region includes one or more quantum wells having a thickness greater than 4 nanometers.

15. The method of claim 14, wherein the quantum wells have a thickness of approximately 8-12 nanometers.

16. The method of claim 14, wherein the quantum wells have a thickness of approximately 10 nanometers.

17. The method of claim 14, wherein the non-polar III-nitride layers comprise m-plane or a-plane III-nitride layers.

18. The method of claim 14, wherein one or more emitting surfaces of the device is roughened, textured, patterned or shaped.

19. The method of claim 18, wherein more than one emitting surface of the device is roughened, textured, patterned or shaped.

20. The method of claim 18, wherein the emitting surface of the device is a cone shaped surface.

21. The method of claim 14, wherein the active region is comprised of multiple emitting layers emitting light at more than one wavelength.

22. The method of claim 14, further comprising forming a transparent electrode layer adjacent the non-polar or semi-polar III-nitride layers.

23. The method of claim 22, wherein the transparent electrode layer is an electrically conductive contact layer.

24. The method of claim 22, wherein a surface of the transparent layer is roughened, textured, patterned or shaped.

25. The method of claim 22, wherein a current spreading layer is deposited before the transparent electrode layer.

26. The method of claim 14, wherein the device is placed on a transparent mounting structure.