Group III nitride compound semiconductor device

• US 6,531,719 B2
• Filed: 06/26/2001
• Issued: 03/11/2003
• Est. Priority Date: 09/29/1999
• Status: Expired due to Term

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Shibata, Naoki, Ito, Jun, Watanabe, Hiroshi, Senda, Masanobu, Chiyo, Toshiaki, Asami, Shizuyo, Asami, Shinya
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): TRAN, LONG K
• Application Number:
  US09/888,519
• Publication Number:
  US 20010050376A1
• Time in Patent Office: 623 Days
• Field of Search: 257/190, 257/79, 257/97, 257/196, 257/101, 257/103, 257/183, 257/201, 257/613, 257/618, 257/622, 257/623
• US Class Current: 257/190
• CPC Class Codes: H01L 31/03042 characterised by the doping material
• CPC Class Codes: H01L 31/03046 including ternary or quaternary compounds, e.g. GaAlAs, InGaAs, InGaAsP
• CPC Class Codes: H01L 31/184 the active layers comprising only AIIIBV compounds, e.g. GaAs, InP
• CPC Class Codes: H01L 31/1852 comprising a growth substrate not being an AIIIBV compound
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• 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: H01L 33/405 Reflective materials
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• CPC Class Codes: Y10S 438/978 forming tapered edges on substrate or adjacent layers

Abstract

A group III nitride compound semiconductor device has a substrate, a group III nitride compound semiconductor layer having a device function, and an undercoat layer formed between the substrate and the group III nitride semiconductor layer. The undercoat layer has a surface which has a texture structure, or which is trapezoid shaped in section or which is pit shaped. In addition, a reflection layer made of nitride of at least one metal selected from the group consisting of titanium, zirconium, hafnium and tantalum may be formed on a surface of the undercoat layer. Also the surface of the reflection layer is formed as a texture structure, a trapezoid shape in section or a pit shape.

Claims

1. A group III nitride compound semiconductor device comprising:

a substrate;

a group III nitride compound semiconductor layer having a device function; and

an undercoat layer formed between said substrate and said group III nitride semiconductor layer, said undercoat layer having a surface of a peak and trough structure.

2. A group III nitride compound semiconductor device according to claim 1, wherein said undercoat layer is formed substantially of a single crystal.

3. A group III nitride compound semiconductor device according to claim 2, wherein said undercoat layer is formed of a group III nitride compound semiconductor and formed on a sapphire substrate.

4. A group III nitride compound semiconductor device according to claim 1, wherein said undercoat layer is made of Al_xGa_1-xN (0≦

x≦

1).

5. A group III nitride compound semiconductor device according to claim 4, wherein said undercoat layer is formed of an AlN layer.

6. A group III nitride compound semiconductor device according to claim 5, wherein said AlN layer has a thickness of from 0.2 to 3.0 μ

m.

7. A group III nitride compound semiconductor device according to claim 5, wherein said AlN layer has a thickness of from 0.5 to 1.5 μ

m.

8. A group III nitride compound semiconductor device according to claim 1, wherein said undercoat layer is formed of a silicon single crystal.

9. A group III nitride compound semiconductor device according to claim 1, further comprising a sedimentary layer interposed between said undercoat layer and said substrate.

10. A group III nitride compound semiconductor device according to claim 1, wherein said substrate is made of one of sapphire, silicon single crystal and silicon carbide single crystal.

11. A group III nitride compound semiconductor device according to claim 1, further comprising a reflection layer formed on said surface of said undercoat layer and made of nitride of at least one kind of metal selected from the group consisting of titanium, zirconium, hafnium and tantalum, said reflection layer having a surface shape formed in accordance with a surface shape of said undercoat layer.

12. A group III nitride compound semiconductor device according to claim 11, wherein said reflection layer is made of titanium nitride.

13. A group III nitride compound semiconductor device according to claim 11, wherein said substrate is made of sapphire, said undercoat layer is made of AIN and having a surface formed as a peak and trough structure, and said reflection layer is made of titanium nitride.

14. A group III nitride compound semiconductor device according to claim 1, wherein the peak and trough structure surface is formed over substantially a whole surface of the substrate.

15. A group III nitride compound semiconductor device according to claim 1, wherein the undercoat layer is formed by metal organic chemical vapor deposition.

16. A group III nitride compound semiconductor device comprising:

a substrate;

a group III nitride compound semiconductor layer having a device function; and

an undercoat layer formed between said substrate and said group III nitride semiconductor layer, said undercoat layer having a surface which is trapezoid shaped in section.

17. A group III nitride compound semiconductor device according to claim 16, wherein said undercoat layer is formed substantially of a single crystal.

18. A group III nitride compound semiconductor device according to claim 17, wherein said undercoat layer is formed of a group III nitride compound semiconductor and formed on a sapphire substrate.

19. A group III nitride compound semiconductor device according to claim 16, wherein said undercoat layer is made of Al_xGa_1-xN (0≦

x≦

1).

20. A group III nitride compound semiconductor device according to claim 19, wherein said undercoat layer is formed of an AlN layer.

21. A group III nitride compound semiconductor device according to claim 20, wherein said AlN layer has a thickness of from 0.2 to 3.0 μ

m.

22. A group III nitride compound semiconductor device according to claim 20, wherein said AlN layer has a thickness of from 0.5 to 1.5 μ

m.

23. A group III nitride compound semiconductor device according to claim 16, wherein said undercoat layer is formed of a silicon single crystal.

24. A group III nitride compound semiconductor device according to claim 16, further comprising a sedimentary layer interposed between said undercoat layer and said substrate.

25. A group III nitride compound semiconductor device according to claim 16, wherein said substrate is made of one of sapphire, silicon single crystal and silicon carbide single crystal.

26. A group III nitride compound semiconductor device according to claim 16, further comprising a reflection layer formed on said surface of said undercoat layer and made of nitride of at least one kind of metal selected from the group consisting of titanium, zirconium, hafnium and tantalum, said reflection layer having a surface shape formed in accordance with a surface shape of said undercoat layer.

27. A group III nitride compound semiconductor device according to claim 26, wherein said reflection layer is made of titanium nitride.

28. A group III nitride compound semiconductor device according to claim 26, wherein said substrate is made of sapphire, said undercoat layer is made of AIN and having a surface formed as a peak and trough structure, and said reflection layer is made of titanium nitride.

29. A group III nitride compound semiconductor device according to claim 16, wherein the trapezoid shaped surface is formed over substantially a whole surface of the substrate.

30. A group III nitride compound semiconductor device according to claim 16, wherein the undercoat layer is formed by metal organic chemical vapor deposition.

31. A group III nitride compound semiconductor device comprising:

a substrate;

a group III nitride compound semiconductor layer having a device function; and

an undercoat layer formed between said substrate and said group III nitride semiconductor layer, said undercoat layer having a surface which is pit shaped.

32. A group III nitride compound semiconductor device according to claim 31, wherein said undercoat layer is formed substantially of a single crystal.

33. A group III nitride compound semiconductor device according to claim 32, wherein said undercoat layer is formed of a group III nitride compound semiconductor and formed on a sapphire substrate.

34. A group III nitride compound semiconductor device according to claim 31, wherein said undercoat layer is made of Al_xGa_1-xN (0≦

x≦

1).

35. A group III nitride compound semiconductor device according to claim 34, wherein said undercoat layer is formed of an AlN layer.

36. A group III nitride compound semiconductor device according to claim 35, wherein said AlN layer has a thickness of from 0.2 to 3.0 μ

m.

37. A group III nitride compound semiconductor device according to claim 35, wherein said AlN layer has a thickness of from 0.5 to 1.5 μ

m.

38. A group III nitride compound semiconductor device according to claim 31, wherein said undercoat layer is formed of a silicon single crystal.

39. A group III nitride compound semiconductor device according to claim 31, further comprising a sedimentary layer interposed between said undercoat layer and said substrate.

40. A group III nitride compound semiconductor device according to claim 31, wherein said substrate is made of sapphire or silicon single crystal.

41. A group III nitride compound semiconductor device according to claim 31, further comprising a reflection layer formed on said surface of said undercoat layer and made of nitride of at least one kind of metal selected from the group consisting of titanium, zirconium, hafnium and tantalum, said reflection layer having a surface shape formed in accordance with a surface shape of said undercoat layer.

42. A group III nitride compound semiconductor device according to claim 41, wherein said reflection layer is made of titanium nitride.

43. A group III nitride compound semiconductor device according to claim 41, wherein said substrate is made of sapphire, said undercoat layer is made of AIN and having a surface formed as a peak and trough structure, and said reflection layer is made of titanium nitride.

44. A group III nitride compound semiconductor device according to claim 31, wherein the pit shaped surface is formed over substantially a whole surface of the substrate.

45. A group III nitride compound semiconductor device according to claim 31, wherein the undercoat layer is formed by metal organic chemical vapor deposition.

46. A group III nitride compound semiconductor device comprising:

a substrate;

a group III nitride compound semiconductor layer having a device function; and

an undercoat layer formed between said substrate and said group III nitride semiconductor layer, said undercoat layer having a surface containing inclined faces, wherein a projected area ratio of said inclined faces to said surface of said undercoat layer on a plane of projection is in a range of from 5 to 100%.

47. A group III nitride compound semiconductor device according to claim 46, wherein the projected area ratio of said inclined faces to said surface of said undercoat layer on a plane of protection is in a range of from 30 to 100%.

48. A group III nitride compound semiconductor device according to claim 46, wherein the projected area ratio of said inclined faces to said surface of said undercoat layer on a plane of protection is in a range of from 70 to 100%.

49. A group III nitride compound semiconductor device according to claim 46, wherein said undercoat layer is formed substantially of a single crystal.

50. A group III nitride compound semiconductor device according to claim 49, wherein said undercoat layer is formed of a group III nitride compound semiconductor and formed on a sapphire substrate.

51. A group III nitride compound semiconductor device according to claim 46, wherein said undercoat layer is made of Al_xGa_1-xN (0≦

x≦

1).

52. A group III nitride compound semiconductor device according to claim 51, wherein said undercoat layer is formed of an AlN layer.

53. A group III nitride compound semiconductor device according to claim 52, wherein said AlN layer has a thickness of from 0.2 to 3.0 μ

m.

54. A group III nitride compound semiconductor device according to claim 52, wherein said AlN layer has a thickness of from 0.5 to 1.5 μ

m.

55. A group III nitride compound semiconductor device according to claim 46, wherein said undercoat layer is formed of a silicon single crystal.

56. A group III nitride compound semiconductor device according to claim 46, further comprising a sedimentary layer interposed between said undercoat layer and said substrate.

57. A group III nitride compound semiconductor device according to claim 46, wherein said substrate is made of one of sapphire, silicon single crystal and silicon carbide single crystal.

58. A group III nitride compound semiconductor device according to claim 46, further comprising a reflection layer formed on said surface of said undercoat layer and made of nitride of at least one kind of metal selected from the group consisting of titanium, zirconium, hafnium and tantalum, said reflection layer having a surface shape formed in accordance with a surface shape of said undercoat layer.

59. A group III nitride compound semiconductor device according to claim 58, wherein said reflection layer is made of titanium nitride.

60. A group III nitride compound semiconductor device according to claim 58, wherein said substrate is made of sapphire, said undercoat layer is made of AIN and having a surface formed as a peak and trough structure, and said reflection layer is made of titanium nitride.

61. A group III nitride compound semiconductor device according to claim 46, wherein the undercoat layer is formed by metal organic chemical vapor deposition.

68. A group III nitride compound semiconductor device according to claim 61, wherein said substrate is formed of sapphire or silicon single crystal.

69. A group III nitride compound semiconductor device according to claim 68, wherein said sedimentary layer is formed on face a of said sapphire substrate.

62. A group III nitride compound semiconductor device comprising:

a substrate;

a group III nitride compound semiconductor layer having a device function;

an undercoat layer formed between said substrate and said group III nitride semiconductor layer; and

a sedimentary layer formed between said undercoat layer and substrate, said undercoat layer being formed of a group III nitride compound semiconductor and having one of a surface of a peak and trough structure, a surface of a sectional trapezoid shape, and a surface of a pit shape, said sedimentary layer being formed of one of a group III nitride compound semiconductor and a metal nitride compound semiconductor.

63. A group III nitride compound semiconductor device according to claim 62, wherein said sedimentary layer is formed as a multilayer containing at least first and second sedimentary layers and another group III nitride compound semiconductor layer is interposed between said first and second sedimentary layers.

64. A group III nitride compound semiconductor device according to claim 62, wherein said sedimentary layer is formed of Al_XGa_1-XN (0≦

X≦

1) and formed at a temperature lower than or equal to that of said undercoat layer.

65. A group III nitride compound semiconductor device according to claim 62, wherein said sedimentary layer is formed of a metal nitride compound semiconductor and formed at a temperature lower than or equal to that of said undercoat layer.

66. A group III nitride compound semiconductor device according to claim 62, wherein said undercoat layer is made of Al_xGa_1-xN (0≦

x≦

1).

67. A group III nitride compound semiconductor device according to claim 66, wherein said sedimentary layer is formed of an AlN layer.

70. A group III nitride compound semiconductor device according to claim 62, further comprising:

a reflection layer formed on said surface of said undercoat layer and made of nitride of at least one kind of metal selected from the group consisting of titanium, zirconium, hafnium and tantalum, said reflection layer having a surface shape formed in accordance with the surface shape of said undercoat layer.

71. A group III nitride compound semiconductor device according to claim 70, wherein said reflection layer is made of titanium nitride.

72. A group III nitride compound semiconductor device according to claim 70, wherein said substrate is made of sapphire, said undercoat layer is made of AIN and having a surface formed as a peak and trough structure, and said reflection layer is made of titanium nitride.

73. A group III nitride compound semiconductor device according to claim 62, wherein said one of a surface of peak and trough structure, trapezoid shape, and pit shape is formed over substantially a whole surface of the substrate.

74. A group III nitride compound semiconductor device according to claim 62, wherein the undercoat layer is formed by metal organic chemical vapor deposition.