Low voltage laser diodes on {20-21} gallium and nitrogen containing substrates

• US 9,543,738 B2
• Filed: 09/16/2010
• Issued: 01/10/2017
• Est. Priority Date: 09/17/2009
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa Laser Diode, Inc. (Kyocera Corporation)
• Inventors: Raring, James W., Schmidt, Mathew, Poblenz, Christiane
• Primary Examiner(s): VAN ROY, TOD THOMAS
• Application Number:
  US12/883,652
• Publication Number:
  US 20110064101A1
• Time in Patent Office: 2,308 Days
• Field of Search: 372/44.011, 372/45.01
• US Class Current: 1/1
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/02389 Nitrides
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/467 using masks
• CPC Class Codes: H01S 5/0014 Measuring characteristics or properties thereof measuring techniques per se G01J, G01K, G01N, G01R
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/227 Buried mesa structure ; Striped active layer
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/3213 asymmetric clading layers
• CPC Class Codes: H01S 5/3407 characterised by special barrier layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

A low voltage laser device having an active region configured for one or more selected wavelengths of light emissions.

Claims

1. A laser diode device comprising:

a gallium and nitrogen containing material including a {20-21} crystalline surface region;

an n-type cladding material overlying the gallium and nitrogen containing material, the n-type cladding material being free from AlGaN;

an active region comprising at least three quantum wells and a plurality of GaN barrier layers, each of the quantum wells having a thickness of 1 nm or greater and less than 4 nm, and each of the plurality of GaN barrier layers being free from Al and having a thickness of between 1.5 nm to 2.5 nm, each adjacent pair of the quantum wells separated by one of the plurality of GaN barrier layers;

a p-type cladding material overlying the active region, the p-type cladding material being free from AlGaN;

a p++ contact region overlying the p-type cladding material;

a laser stripe region overlying the crystalline surface region, the laser stripe region being aligned substantially in a projection of the c-direction, the laser stripe region comprising a first end and a second end;

a first facet formed on the first end; and

a second facet formed on the second end;

wherein the active region is configured to operate at a forward voltage of less than 7 volts.

2. The device of claim 1 wherein the active region comprises at least four quantum wells.

3. The device of claim 1 wherein the active region comprises at least five quantum wells.

4. The device of claim 1 wherein the active region comprises at least six quantum wells.

5. The device of claim 1 wherein the active region comprises at least seven quantum wells.

6. The device of claim 1 wherein each of the plurality of GaN barrier layers is about 2 nm in thickness.

7. The device of claim 1 wherein each of the quantum wells is about 2.5 nm to 3.5 nm in thickness.

8. The device of claim 1 wherein the device is operable as a laser diode operating in the green wavelength regime of 500-540 nm.

9. The device of claim 1 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 3% at 60 mW or greater.

10. The device of claim 1 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 5% at 60 mW or greater.

11. The device of claim 1 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 8% at 60 mW or greater.

12. The device of claim 1 further comprising an n-side SCH optical guiding region between the n-type cladding material and the active region.

13. The device of claim 1 wherein each of the plurality of barrier layers is less than about 2.0 nm in thickness.

14. The device of claim 1 wherein the active region is configured operably for the forward voltage of less than 7 volts for an output power of 60 mW and greater.

15. The device of claim 1 wherein the gallium and nitrogen containing material is a substrate.

16. A laser diode device comprising:

a gallium and nitrogen containing material including a {20-21}crystalline surface region;

an n-type cladding material overlying the gallium and nitrogen containing material;

an active region comprising at least three quantum wells and a plurality of barrier layers, each of the quantum wells having a thickness of 1 nm or greater, and each of the plurality of barrier layers having an n-type impurity characteristic and a thickness of 1 nm or greater and less than 3 nm, each adjacent pair of the quantum wells separated by one of the plurality of barrier layers;

a p-type cladding material overlying the active region, the p-type cladding material being free from AlGaN;

a p-type material overlying the p-type cladding material;

a laser stripe region overlying the crystalline surface region, the laser stripe region being aligned substantially in a projection of the c-direction, the laser stripe region comprising of a first end and a second end;

a first facet formed on the first end; and

a second facet formed on the second end,

wherein the active region is configured to operate at a forward voltage of less than 7 volts.

17. The device of claim 16 wherein the active region comprises at least four quantum wells.

18. The device of claim 16 wherein the active region comprises at least five quantum wells.

19. The device of claim 16 wherein the active region comprises at least six quantum wells.

20. The device of claim 16 further comprising an SCH region between the n-type cladding material and the active region and/or between the p-type cladding and the active region.

21. The device of claim 16 wherein the active region is configured operably for a forward voltage of <

7 v for an output power of 60 mW and greater.

22. The device of claim 16 wherein the active region is configured operably for a forward voltage of <

6 v for an output power of 60 mW and greater.

23. The device of claim 16 wherein the device is operable as a laser diode operating in a green wavelength regime of 500-540 nm.

24. The device of claim 16 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 3% at 60 mW or greater.

25. The device of claim 16 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 5% at 60 mW or greater.

26. The device of claim 16 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 8% at 60 mW or greater.

27. The device of claim 16 wherein the device is operable as a laser diode with a wall-plug efficiency of greater than 10% at 60 mW or greater.

28. The device of claim 16 wherein each of the plurality of barrier layers is at least about 2 nm in thickness.

29. The device of claim 16 wherein each of the plurality of barrier layers is at least about 1.5 nm to about 2.5 nm in thickness.

30. The device of claim 16 wherein each of the quantum wells is about 2.5 nm to about 3.5 nm in thickness.

31. The device of claim 16 wherein each of the quantum wells is about 3.5 nm to about 4.5 nm in thickness.

32. The device of claim 16 wherein each of the quantum wells is about 4 nm to about 5.5 nm in thickness.

33. The device of claim 16 wherein each of the quantum wells is about 5.5 nm to about 8 nm in thickness.

34. The device of claim 16 further comprising an n-side SCH region between the n-type cladding material and the active region.

35. The device of claim 16 further comprising a p-side SCH region between the p-type cladding material and the active region.

36. The device of claim 16 further comprising an electron blocking region between the active region and the p-type cladding material.

37. The device of claim 16 wherein at least one of the plurality of barrier layers comprise a material selected from GaN, InGaN, AlGaN, and InAlGaN.

38. The device of claim 16 wherein each of the quantum wells comprises at least InGaN.

39. The device of claim 16 wherein the active region is configured to emit electromagnetic radiation ranging from about 390 nm to about 420 nm.

40. The device of claim 16 wherein the active region is configured to emit electromagnetic radiation ranging from about 420 nm to about 460 nm.

41. The device of claim 16 wherein the active region is configured to emit electromagnetic radiation ranging from about 460 nm to about 500 nm.

42. The device of claim 16 wherein the active region is configured to emit electromagnetic radiation ranging from about 540 nm and greater.

43. The device of claim 16 wherein the n-type impurity characteristic comprises a silicon bearing species.

44. The device of claim 16, wherein each of the quantum wells is 1 nm to 20 nm in thickness.

45. The device of claim 16 wherein the gallium and nitrogen containing material is a substrate.

46. A laser diode device comprising:

an n-type gallium and nitrogen containing material including a {20-21} crystalline surface region;

an n-type cladding material overlying the n-type gallium and nitrogen containing material, the n-type cladding material being substantially free from aluminum bearing material;

an active region comprising at least three quantum wells and a plurality of barrier layers, each of the quantum wells having a thickness of 1 nm or greater, and each of the plurality of barrier layers having a thickness of 1 nm or greater and less than 3 nm, each adjacent pair of the quantum wells separated by one of the plurality of barrier layers;

a p-type cladding material overlying the active region, the p-type cladding material being free from AlGaN;

a laser stripe region overlying the crystalline surface region, the laser stripe region being aligned substantially in a projection of the c-direction, the laser stripe region comprising a first end and a second end;

a first facet formed on the first end; and

a second facet formed on the second end;

wherein the active region is configured to operate at a forward voltage of less than 7 volts.

47. The device of claim 46 wherein the active region comprises at least three quantum wells;

and further comprises a p++ contact region overlying the p-type cladding material.

48. The device of claim 46 wherein the active region comprises at least five quantum wells.

49. The device of claim 46 wherein each of the plurality of barrier layers is about 1.5 nm to about 2.5 nm in thickness.

50. The device of claim 46 wherein each of the plurality of barrier layers is greater than 2 nm in thickness.

51. The device of claim 46 wherein each of the quantum wells is about 2 nm to about 4 nm in thickness.

52. The device of claim 46 wherein each of the quantum wells is about 4 nm to about 6 nm in thickness.

53. The device of claim 46 wherein the device is operable as a laser diode operating in the green wavelength regime of 500 nm to 540 nm.

54. The device of claim 46 wherein each of the quantum wells is 1 nm to 20 nm in thickness.

55. The device of claim 46 wherein the gallium and nitrogen containing material is a substrate.