Semiconductor light emitting device and its manufacturing method

• US 20030136970A1
• Filed: 01/23/2003
• Published: 07/24/2003
• Est. Priority Date: 01/24/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ikeda, Masao, Asano, Takeharu, Takeya, Motonobu
• Granted Patent: US 6,870,193 B2
• Time in Patent Office: Days
• US Class Current: 257/90
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/2004 Confining in the direction perpendicular to the layer structure
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

In a semiconductor light emitting device such as a semiconductor laser using nitride III-V compound semiconductors and having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, the p-side cladding layer is made of an undoped or n-type first layer 9 and a p-type second layer 12 that are deposited sequentially from nearer to remoter from the active layer. The first layer 9 is not thinner than 50 nm. The p-type second layer 12 includes a p-type third layer having a larger band gap inserted therein as an electron blocking layer. Thus the semiconductor light emitting device is reduced in operation voltage while keeping a thickness of the p-side cladding layer necessary for ensuring favorable optical properties.

Claims

1. A semiconductor light emitting device made by using nitride III-V compound semiconductors, which has a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, and the second layer including a third layer having a larger band gap than the second layer.

2. The semiconductor light emitting device according to claim 1 wherein an n-side optical waveguide layer is interposed between the n-side cladding layer and the active layer, and a p-side optical waveguide layer is interposed between the p-side cladding layer and the active layer.

3. The semiconductor light emitting device according to claim 1 wherein the second layer of the p-side cladding layer has a thickness in the range larger than 0 nm and not exceeding 550 nm.

4. The semiconductor light emitting device according to claim 1 wherein thickness of the second layer of the p-side cladding layer is in the range from 390 nm to 550 nm.

5. The semiconductor light emitting device according to claim 1 wherein thickness of the first layer of the p-side cladding layer is in the range larger than 0 nm and not exceeding 500 nm.

6. The semiconductor light emitting device according to claim 1 wherein thickness of the first layer of the p-side cladding layer is not thinner than 50 nm.

7. The semiconductor light emitting device according to claim 1 wherein thickness of the first layer of the p-side cladding layer is in the range from 50 nm to 400 nm.

8. The semiconductor light emitting device according to claim 1 wherein the first layer of the p-side cladding layer has a superlattice structure.

9. The semiconductor light emitting device according to claim 1 wherein the p-side cladding layer has a superlattice structure.

10. The semiconductor light emitting device according to claim 1 wherein the third layer is made of a p-type nitride III-V compound semiconductor containing Al and Ga.

11. The semiconductor light emitting device according to claim 1 wherein the third layer is made of p-type Al_xGa₁₋

xN (where 0<

x<

1).

12. The semiconductor light emitting device according to claim 1 wherein the third layer is made of p-type Al_xGa₁₋

xN (where 0.15≦

x<

1).

13. The semiconductor light emitting device according to claim 1 wherein distance between the active layer and the second layer of the p-side cladding layer is not less than 20 nm.

14. The semiconductor light emitting device according to claim 1 wherein distance between the active layer and the second layer of the p-side cladding layer is in the range from 100 nm to 180 nm.

15. The semiconductor light emitting device according to claim 1 wherein at least one set of combined layers different in band gap or lattice constant exists between the active layer and the second layer of the p-side cladding layer.

16. The semiconductor light emitting device according to claim 1 wherein at least one layer of superlattice structure made of layers different in atomic composition ratio exists between the active layer and the second layer of the p-type cladding layer.

17. The semiconductor light emitting device according to claim 1 wherein the first layer of the p-side cladding layer is made of p-type Al_yGa₁₋

yN (where 0<

y≦

0.04).

18. A semiconductor light emitting device made by using nitride III-V compound semiconductors, which has a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer, and the first layer having a thickness not thinner than 50 nm.

19. The semiconductor light emitting device according to claim 18 wherein the second layer of the p-side cladding layer has a thickness in the range larger than 0 nm and not exceeding 550 nm.

20. The semiconductor light emitting device according to claim 18 wherein thickness of the second layer of the p-side cladding layer is in the range from 390 nm to 550 nm.

21. The semiconductor light emitting device according to claim 18 wherein thickness of the first layer of the p-side cladding layer is in the range from 50 nm to 400 nm.

22. The semiconductor light emitting device according to claim 18 wherein distance between the active layer and the second layer of the p-side cladding layer is not less than 20 nm.

23. The semiconductor light emitting device according to claim 18 wherein distance between the active layer and the second layer of the p-side cladding layer is in the range from 100 nm to 180 nm.

24. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer, and the first layer having a thickness not thinner than 50 nm.

25. The semiconductor light emitting device according to claim 24 wherein the second layer of the p-side cladding layer has a thickness in the range larger than 0 nm and not exceeding 550 nm.

26. The semiconductor light emitting device according to claim 24 wherein thickness of the second layer of the p-side cladding layer is in the range from 390 nm to 550 nm.

27. The semiconductor light emitting device according to claim 24 wherein distance between the active layer and the second layer of the p-side cladding layer is not less than 20 nm.

28. The semiconductor light emitting device according to claim 24 wherein distance between the active layer and the second layer of the p-side cladding layer is in the range from 100 nm to 180 nm.

29. A semiconductor light emitting device made by using nitride III-V compound semiconductors, which has a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and includes a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer, and the second layer including a third layer having a larger band gap than the second layer; and

p-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm.

30. The semiconductor light emitting device according to claim 29 wherein p-type layers in opposite sides of the ridge have a thickness in the range from 0 to 50 nm.

31. A semiconductor light emitting device made by using nitride III-V compound semiconductors, and having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer, and the second layer including a third layer having a larger band gap than the second layer; and

bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer.

32. The semiconductor light emitting device according to claim 31 wherein the bottom surfaces of portions in opposite sides of the ridge are positioned in the first layer.

33. A semiconductor light emitting device made by using nitride III-V compound semiconductors, which has a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and has a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer; and

p-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm.

34. The semiconductor light emitting device according to claim 33 wherein p-type layers in opposite sides of the ridge have a thickness in the range from 0 to 50 nm.

35. A semiconductor light emitting device made by using nitride III-V compound semiconductors, which has a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and has a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer; and

bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer.

36. The semiconductor light emitting device according to claim 35 wherein the bottom surfaces of portions in opposite sides of the ridge are positioned in the first layer.

37. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and having a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer; and

p-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm.

38. The semiconductor light emitting device according to claim 37 wherein p-type layers in opposite sides of the ridge have a thickness in the range from 0 to 50 nm.

39. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and having a ridge structure, comprising:

the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity in this order from one side nearer to the active layer; and

bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer.

40. The semiconductor light emitting device according to claim 39 wherein the bottom surfaces of portions in opposite sides of the ridge are positioned in the first layer.

41. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, and the second layer including a third layer having a larger band gap than the second layer, comprising:

growing layers from the active layer to the third layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

42. The method of manufacturing a semiconductor light emitting device according to claim 41 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

43. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, and the first layer having a thickness not thinner than 50 nm, comprising:

growing layers from the active layer to the first layer of the p-side cladding layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

44. The method of manufacturing a semiconductor light emitting device according to claim 43 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

45. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and have a ridge structure, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, the second layer including a third layer having a larger band gap than the second layer, and p-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm, comprising:

growing layers from the active layer to the third layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

46. The method of manufacturing a semiconductor light emitting device according to claim 45 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

47. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and have a ridge structure, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, the second layer including a third layer having a larger band gap than the second layer, and bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer, comprising:

growing layers from the active layer to the third layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

48. The method of manufacturing a semiconductor light emitting device according to claim 47 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

49. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and have a ridge structure, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, and p-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm, comprising:

growing layers from the active layer to the first layer of the p-side cladding layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

50. The method of manufacturing a semiconductor light emitting device according to claim 49 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

51. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer and have a ridge structure, the p-side cladding layer including an undoped or n-type first layer and a p-type second layer doped with a p-type impurity which lie in this order from one side nearer the active layer, and bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer, comprising:

growing layers from the active layer to the first layer of the p-side cladding layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

52. The method of manufacturing a semiconductor light emitting device according to claim 51 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

53. A semiconductor light emitting device composed of nitride III-V compound semiconductors and having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, comprising:

distance between the active layer and one of p-type layers doped with a p-type impurity nearest to the active layer being not less than 50 nm.

54. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is not less than 60 nm.

55. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is not less than 100 nm.

56. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is in the range from 50 to 500 nm.

57. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is in the range from 100 to 200 nm.

58. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is in the range from 65 to 230 nm.

59. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is in the range from 70 to 125 nm.

60. The semiconductor light emitting device according to claim 53 wherein the distance between the active layer and the p-type layer is in the range from 90 to 110 nm.

61. The semiconductor light emitting device according to claim 53 wherein the p-type layer nearest to the active layer has a larger band gap than that of the p-side cladding layer.

62. The semiconductor light emitting device according to claim 53 wherein at least one layer different in composition from the active layer and the p-side cladding layer is interposed between the active layer and the p-side cladding layer.

63. A method of manufacturing a semiconductor light emitting device composed of nitride III-V compound semiconductors to have a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, in which the distance between the active layer and one of p-type layers doped with a p-type impurity nearest to the active layer is not less than 50 nm, and the p-type layer nearest to the active layer has a larger band gap than the p-side cladding layer, comprising:

growing layers from the active layer to said p-type layer having a larger band gap than the p-side cladding layer in a carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen.

64. The method of manufacturing a semiconductor light emitting device according to claim 63 wherein the carrier gas atmosphere containing nitrogen as a major component thereof and containing substantially no hydrogen is N₂ gas atmosphere.

65. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, comprising:

the n-side cladding layer including an undoped or p-type first layer and an n-type second layer doped with an n-type impurity in this order from one side nearer to the active layer, and the first layer having a thickness not smaller than 50 nm.

66. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, and having a ridge structure, comprising:

the n-side cladding layer including an undoped or p-type first layer and an n-type second layer doped with an n-type impurity in this order from one side nearer to the active layer; and

n-type layers in opposite sides of the ridge having a thickness in the range from 0 to 100 nm.

67. A semiconductor light emitting device having a structure interposing an active layer between an n-side cladding layer and a p-side cladding layer, and having a ridge structure, comprising:

the n-side cladding layer including an undoped or p-type first layer and an n-type second layer doped with an n-type impurity in this order from one side nearer to the active layer; and

bottom surfaces of portions in opposite sides of the ridge being deeper than the boundary between the first layer and the second layer.