Semiconductor device having thin film transistor with position controlled channel formation region

• US 7,148,507 B2
• Filed: 12/17/2004
• Issued: 12/12/2006
• Est. Priority Date: 01/17/2002
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Isobe, Atsuo, Shibata, Hiroshi, Miyairi, Hidekazu, Shimomura, Akihisa, Tanaka, Koichiro, Akiba, Mai, Hayakawa, Masahiko, Yamazaki, Shunpei, Arao, Tatsuya, Dairiki, Koji, Kokubo, Chiho
• Primary Examiner(s): CHAET, MARISSA W
• Application Number:
  US11/013,539
• Publication Number:
  US 20050098784A1
• Time in Patent Office: 725 Days
• Field of Search: 257 59- 72, 257/75, 257/347, 257/350
• US Class Current: 257/64
• CPC Class Codes: B23K 26/0738 into a linear shape
• CPC Class Codes: H01L 21/02354 using a coherent radiation, e.g. a laser
• CPC Class Codes: H01L 21/02356 treatment to change the morphology of the insulating layer, e.g. transformation of an amorphous layer into a crystalline layer
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02425 Conductive materials, e.g. metallic silicides
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/02675 using laser beams
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02683 Continuous wave laser beam
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• CPC Class Codes: H01L 21/32139 using masks
• CPC Class Codes: H01L 21/84 the substrate being other than a semiconductor body, e.g. being an insulating body
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/124 : with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 : integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1274 : using crystallisation of amorphous semiconductor or recrystallisation of crystalline semiconductor
• CPC Class Codes: H01L 27/1281 : by using structural features to control crystal growth, e.g. placement of grain filters
• CPC Class Codes: H01L 27/1296 : adapted to increase the uniformity of device parameters
• CPC Class Codes: H01L 29/66757 : Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78603 : characterised by the insulating substrate or support H01L29/78657 takes precedence
• CPC Class Codes: H01L 29/78675 : with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78696 : characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: Y10S 118/90 : Semiconductor vapor doping
• CPC Class Codes: Y10T 117/10 : Apparatus
• CPC Class Codes: Y10T 117/1004 : with means for measuring, testing, or sensing
• CPC Class Codes: Y10T 117/1008 : with responsive control means

Abstract

A semiconductor device production system using a laser crystallization method is provided which can avoid forming grain boundaries in a channel formation region of a TFT, thereby preventing grain boundaries from lowering the mobility of the TFT greatly, from lowering ON current, and from increasing OFF current. Rectangular or stripe pattern depression and projection portions are formed on an insulating film. A semiconductor film is formed on the insulating film. The semiconductor film is irradiated with continuous wave laser light by running the laser light along the stripe pattern depression and projection portions of the insulating film or along the major or minor axis direction of the rectangle. Although continuous wave laser light is most preferred among laser light, it is also possible to use pulse oscillation laser light in irradiating the semiconductor film.

Claims

1. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion; and

a thin film transistor having a channel formation region that is placed only between a center and an edge of the depression portion of the insulating film.

2. The semiconductor device according to claim 1, wherein a bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

3. The semiconductor device according to claim 1, wherein the depression portion of the insulating film is formed not forming an insulating film comprising a silicon nitride film or a silicon oxynitride film.

4. The semiconductor device according to claim 1, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

5. The semiconductor device according to claim 1, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

6. The semiconductor device according to claim 1, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

7. The semiconductor device according to claim 1, wherein the depression portion is a rectangular or stripe pattern.

8. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion; and

a thin film transistor having a channel formation region over the depression portion that is not placed over a midpoint of the depression portion of the insulating film.

9. The semiconductor device according to claim 8, wherein a bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

10. The semiconductor device according to claim 8, wherein the depression portion of the insulating film is formed not forming an insulating film comprising a silicon nitride film or a silicon oxynitride film.

11. The semiconductor device according to claim 8, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

12. The semiconductor device according to claim 8, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

13. The semiconductor device according to claim 8, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

14. The semiconductor device according to claim 8, wherein the depression portion is a rectangular or stripe pattern.

15. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion; and

a thin film transistor having a channel formation region that is placed only between a center and an edge of the projection portion of the insulating film.

16. The semiconductor device according to claim 15, wherein a top of the projection portion is wider than a bottom of the depression portion in a direction perpendicular to the longitudinal direction.

17. The semiconductor device according to claim 15, wherein the projection portion of the insulating film is formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film.

18. The semiconductor device according to claim 15, wherein the projection portion of the insulating film is trapezoidal in section in a direction perpendicular to the longitudinal direction.

19. The semiconductor device according to claim 15, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

20. The semiconductor device according to claim 15, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

21. The semiconductor device according to claim 15, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

22. The semiconductor device according to claim 15, wherein the projection portion is a rectangular or stripe pattern.

23. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion; and

a thin film transistor having a channel formation region over the projection portion that is not placed over a midpoint of the projection portion of the insulating film.

24. The semiconductor device according to claim 23, wherein a top of the projection portion is wider than a bottom of the depression portion in a direction perpendicular to the longitudinal direction.

25. The semiconductor device according to claim 23, wherein the projection portion of the insulating film is formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film.

26. The semiconductor device according to claim 23, wherein the projection portion of the insulating film is trapezoidal in section in a direction perpendicular to the longitudinal direction.

27. The semiconductor device according to claim 23, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

28. The semiconductor device according to claim 23, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

29. The semiconductor device according to claim 23, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

30. The semiconductor device according to claim 23, wherein the projection portion is a rectangular or stripe pattern.

31. A semiconductor device comprising:

an insulating film having a rectangular or stripe pattern depression portion and projection portion; and

a thin film transistor having a channel formation region that is placed only between a center and an edge of the depression portion of the insulating film.

32. The semiconductor device according to claim 31, wherein a bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

33. The semiconductor device according to claim 31, wherein the depression portion and the projection portion of the insulating film are formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film forming a rectangular or stripe pattern on the first insulating film.

34. The semiconductor device according to claim 31, wherein the projection portion of the insulating film is trapezoidal in section in a direction perpendicular to the longitudinal direction.

35. The semiconductor device according to claim 31, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

36. The semiconductor device according to claim 31, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

37. The semiconductor device according to claim 31, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

38. A semiconductor device comprising:

an insulating film having a rectangular or stripe pattern depression portion and projection portion; and

a thin film transistor having a channel formation region over the depression portion that is not placed over a midpoint of the depression portion of the insulating film.

39. The semiconductor device according to claim 38, wherein a bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

40. The semiconductor device according to claim 38, wherein the depression portion and the projection portion of the insulating film are formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film forming a rectangular or stripe pattern on the first insulating film.

41. The semiconductor device according to claim 38, wherein the projection portion of the insulating film are trapezoidal in section in a direction perpendicular to the longitudinal direction.

42. The semiconductor device according to claim 38, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

43. The semiconductor device according to claim 38, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

44. The semiconductor device according to claim 38, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

45. A semiconductor device comprising:

an insulating film having a rectangular or stripe pattern depression portion and projection portion; and

a thin film transistor having a channel formation region that is placed only between a center and an edge of the projection portion of the insulating film.

46. The semiconductor device according to claim 45, wherein a top of the projection portion of the insulating film is wider than a bottom of the depression portion in a direction perpendicular to the longitudinal direction.

47. The semiconductor device according to claim 45, wherein the depression portion and the projection portion of the insulating film are formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film forming a rectangular or stripe pattern on the first insulating film.

48. The semiconductor device according to claim 45, wherein the projection portion of the insulating film is trapezoidal in section in a direction perpendicular to the longitudinal direction.

49. The semiconductor device according to claim 45, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

50. The semiconductor device according to claim 45, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

51. The semiconductor device according to claim 45, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

52. A semiconductor device comprising:

an insulating film having a rectangular or stripe pattern depression portion and projection portion; and

a thin film transistor having a channel formation region over the projection portion that is not placed over a midpoint of the projection portion of the insulating film.

53. The semiconductor device according to claim 52, wherein a top of the projection portion of the insulating film is wider than a bottom of the depression portion in a direction perpendicular to the longitudinal direction.

54. The semiconductor device according to claim 52, wherein the depression portion and the projection portion of the insulating film are formed by a first insulating film and a second insulating film, the first insulating film comprising a silicon oxide film or a silicon oxynitride film, and the second insulating film comprising a silicon nitride film or a silicon oxynitride film forming a rectangular or stripe pattern on the first insulating film.

55. The semiconductor device according to claim 52, wherein the projection portion of the insulating film is trapezoidal in section in a direction perpendicular to the longitudinal direction.

56. The semiconductor device according to claim 52, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

57. The semiconductor device according to claim 52, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

58. The semiconductor device according to claim 52, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

59. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion;

a first thin film transistor having a channel formation region that is placed only between a center and an edge of the depression portion of the insulating film; and

a second thin film transistor over the first thin film transistor.

60. The semiconductor device according to claim 59, wherein bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

61. The semiconductor device according to claim 59, wherein the depression portion of the insulating film is formed not forming an insulating film comprising a silicon nitride film or a silicon oxynitride film.

62. The semiconductor device according to claim 59, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

63. The semiconductor device according to claim 59, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

64. The semiconductor device according to claim 59, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

65. The semiconductor device according to claim 59, wherein the depression portion is a rectangular or stripe pattern.

66. A semiconductor device comprising:

an insulating film having a depression portion and a projection portion;

a first thin film transistor having a channel formation region over the depression portion that is not placed over a midpoint of the depression portion of the insulating film; and

a second thin film transistor over the first thin film transistor.

67. The semiconductor device according to claim 66, wherein a bottom of the depression portion of the insulating film is wider than a top of the projection portion in a direction perpendicular to the longitudinal direction.

68. The semiconductor device according to claim 66, wherein the depression portion of the insulating film is formed not forming an insulating film comprising a silicon nitride film or a silicon oxynitride film forming a rectangular or stripe pattern.

69. The semiconductor device according to claim 66, wherein an oxygen concentration in the channel formation region is 2×

10¹⁹ atoms/cm³ or less.

70. The semiconductor device according to claim 66, wherein a carbon concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

71. The semiconductor device according to claim 66, wherein a nitrogen concentration in the channel formation region is 1×

10¹⁹ atoms/cm³ or less.

72. The semiconductor device according to claim 66, wherein the depression portion is a rectangular or stripe pattern.