Semiconductor device having interlayer insulating film

• US 6,566,711 B1
• Filed: 06/25/1999
• Issued: 05/20/2003
• Est. Priority Date: 08/23/1991
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nemoto, Hideki, Hiroki, Masaaki, Mase, Akira, Takemura, Yasuhiko, Uochi, Hideki, Yamazaki, Shunpei, Zhang, Hongyong
• Primary Examiner(s): Wilson, Allan R.
• Application Number:
  US09/344,373
• Time in Patent Office: 1,425 Days
• Field of Search: 257/59-72, 257/49, 257/344-354, 257/408, 349/54, 349/69, 349/87, 349/88
• US Class Current: 257/347
• CPC Class Codes: G02F 1/136245 having complementary transistors
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 2300/0823 used to establish symmetry in driving, e.g. with polarity inversion
• 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 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• CPC Class Codes: H04N 3/127 using liquid crystals

Abstract

An insulated-gate field-effect transistor adapted to be used in an active-matrix liquid-crystal display. The channel length, or the distance between the source region and the drain region, is made larger than the length of the gate electrode taken in the longitudinal direction of the channel. Offset regions are formed in the channel region on the sides of the source and drain regions. No or very weak electric field is applied to these offset regions from the gate electrode.

Claims

1. An active matrix display device having at least one thin film transistor comprising:

a semiconductor layer formed over a substrate having an insulating surface;

a first pair of impurity regions formed in said semiconductor layer wherein said first pair of impurity regions include an impurity having one conductivity type at a first concentration;

a channel region formed in said semiconductor layer between said pair of impurity regions;

a second pair of impurity regions formed between said first pair of impurity regions and said channel region wherein said second pair of impurity regions include said impurity having said conductivity type at a second concentration lower than said first concentration;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film formed over said semiconductor layer;

an organic resin film formed over said interlayer insulating film, said organic resin film having a leveled upper surface; and

a pixel electrode formed over said organic resin film and electrically connected to said semiconductor layer.

2. A device according to claim 1 wherein said second pair of impurity regions are lightly doped drain regions.

3. A device according to claim 1 wherein said semiconductor layer has a hole mobility not lower than 10 cm²/Vsec or an electron mobility not lower than 15 cm²/Vsec.

4. A device according to claim 1 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

5. A device according to claim 1 wherein said interlayer insulating film comprises silicon oxide.

6. A device according to claim 1 wherein said pixel electrode is transparent.

7. A device according to claim 1 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

8. A device according to claim 1 wherein said thin film transistor is a top-gate type transistor.

9. A device according to claim 1 wherein said device is a liquid crystal display device.

56. A device according to claim 1 further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

114. A device according to claim 1 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor layer having second source, channel, drain regions, and wherein the second source and drain regions include an impurity opposite to said first pair of impurity regions of said thin film transistor.

10. An active matrix device having a thin film transistor, comprising:

a semiconductor island comprising silicon formed over a substrate;

a channel region in said semiconductor island;

source and drain regions with said channel region interposed therebetween;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions of said thin film transistor through a first contact hole of said interlayer insulating film;

a planarizing film comprising an organic resin formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer through a second contact hole of said planarizing film,

wherein said second contact hole does not overlap said first contact hole.

11. A device according to claim 10 wherein said conductive layer comprises aluminum.

12. A device according to claim 10 wherein said gate electrode is located over said channel region.

13. A device according to claim 10 wherein said interlayer insulating film comprises silicon oxide.

14. A device according to claim 10 wherein said planarizing film comprises polyimide.

15. A device according to claim 10 wherein said semiconductor island has a hole mobility not lower than 10 cm²/Vsec or an electron mobility not lower than 15 cm²/Vsec.

16. A device according to claim 10 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

17. A device according to claim 10 wherein said pixel electrode is transparent.

18. A device according to claim 10 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

19. A device according to claim 10 wherein said device is a liquid crystal display device.

25. A device according to claim 10 wherein said semiconductor island has a hole mobility not lower than 10 cm²/Vsec or an electron mobility not lower than 15 cm²/Vsec.

28. A device according to claim 10 further comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

57. A device according to claim 10, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

108. A device according to claim 10 further comprising at least one offset region in said semiconductor island.

115. A device according to claim 10 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor island having second source, channel, drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

20. An active matrix device having a thin film transistor, comprising:

a semiconductor island comprising silicon formed over a substrate;

a channel region in said semiconductor island;

source and drain regions with said channel region interposed therebetween; and

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions of said thin film transistor through a first contact hole of said interlayer insulating film;

a planarizing film comprising an organic resin formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer through a second contact hole of said planarizing film,

wherein said conductive layer has an extended portion which extends from said first contact hole and said pixel electrode contacts said extended portion.

21. A device according to claim 20 wherein said conductive layer comprises aluminum.

22. A device according to claim 20 wherein said gate electrode is located over said channel region.

23. A device according to claim 20 wherein said interlayer insulating film comprises silicon oxide.

24. A device according to claim 20 wherein said planarizing film comprises polyimide.

26. A device according to claim 20 wherein said pixel electrode is transparent.

27. A device according to claim 20 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

29. A device according to claim 20 further comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

58. A device according to claim 20, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

109. A device according to claim 20 further comprising at least one offset region in said semiconductor island.

116. A device according to claim 20 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor island having second source, channel, drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

30. A semiconductor device having at least one thin film transistor comprising:

a semiconductor layer formed over a substrate having an insulating surface, said semiconductor layer comprising source and drain regions including an impurity having one conductivity type at a first concentration, a channel region formed between said source and drain regions, and at least one lightly doped drain region formed between one of said source and drain regions and said channel region, wherein said lightly doped drain region includes said impurity at a second concentration lower than said first concentration;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

a first interlayer insulating film formed over said semiconductor layer and said gate electrode;

a second interlayer insulating film formed over said first interlayer insulating film, said second interlayer insulating film having a leveled upper surface; and

a pixel electrode formed on said leveled upper surface of said second interlayer insulating film.

31. A device according to claim 30 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

32. A device according to claim 30 wherein said first interlayer insulating film comprises silicon oxide.

33. A device according to claim 30 wherein said pixel electrode is transparent.

34. A device according to claim 30 wherein said first interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

35. A device according to claim 30 wherein said thin film transistor is a top-gate type thin film transistor.

36. A device according to claim 30 wherein said semiconductor device comprises a liquid crystal display device.

37. A device according to claim 30 wherein said second interlayer insulating film comprises an organic resin.

59. A device according to claim 30, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

117. A device according to claim 30 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor layer having second source, channel, drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

38. An active matrix device having a thin film transistor formed over an substrate, comprising:

a semiconductor island formed over a substrate having an insulating surface, said semiconductor island comprising silicon, said semiconductor island having a at least channel, source, and drain regions;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions through a first contact hole of said interlayer insulating film;

a planarizing film formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer through a second contact hole of said planarizing film,

wherein said second contact hole does not overlap said first contact hole.

39. A device according to claim 38 comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

40. A device according to claim 38 wherein said conductive layer comprises aluminum.

41. A device according to claim 38 wherein said gate electrode is located over said channel region.

42. A device according to claim 38 wherein said interlayer insulating film comprises silicon oxide.

43. A device according to claim 38 wherein said planarizing film comprises polyimide.

44. A device according to claim 38 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

45. A device according to claim 39 wherein said pixel electrode is transparent.

46. A device according to claim 39 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

47. A device according to claim 39 wherein said semiconductor device has a liquid crystal display device.

60. A device according to claim 38, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

110. A device according to claim 38 further comprising at least one offset region in said semiconductor island.

118. A device according to claim 38 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor island having second source, channel, drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

48. An active matrix device having a thin film transistor formed over a substrate, comprising:

a semiconductor island comprising silicon formed over a substrate having an insulating surface, said semiconductor island having at least channel, source, and drain regions; and

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source or drain regions through a first contact hole of said interlayer insulating film;

a planarizing film formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer through a second contact hole of said planarizing film,

wherein said conductive layer has an extended portion which extends from said first contact hole and said pixel electrode contacts said extended portion.

49. A device according to claim 48 comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

50. A device according to claim 48 wherein said conductive layer comprises aluminum.

51. A device according to claim 48 wherein said gate electrode is located over said channel region.

52. A device according to claim 48 wherein said interlayer insulating film comprises silicon oxide.

53. A device according to claim 48 wherein said planarizing film comprises polyimide.

54. A device according to claim 48 wherein said pixel electrode is transparent.

55. A device according to claim 48 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

61. A device according to claim 48, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

111. A device according to claim 48 further comprising at least one offset region in said semiconductor island.

119. A device according to claim 48 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor island having second source, channel, and drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

62. An active matrix device having a thin film transistor, comprising:

a semiconductor layer formed over a substrate having an insulating surface, said semiconductor layer comprising source and drain regions including an impurity having one conductivity type at a first concentration, a channel region formed between said source and drain regions, and at least one lightly doped drain region formed between one of said source and drain regions and said channel region, wherein said lightly doped drain region includes said impurity at a second concentration lower than said first concentration;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions of said thin film transistor;

a planarizing film comprising an organic resin formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer.

63. A device according to claim 62 wherein said conductive layer comprises aluminum.

64. A device according to claim 62 wherein said gate electrode is located over said channel region.

65. A device according to claim 62 wherein said interlayer insulating film comprises silicon oxide.

66. A device according to claim 62 wherein said planarizing film comprises polyimide.

67. A device according to claim 62 wherein said semiconductor island has a hole mobility not lower than 10 cm²/Vsec or an electron mobility not lower than 15 cm²/Vsec.

68. A device according to claim 62 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

69. A device according to claim 62 wherein said pixel electrode is transparent.

70. A device according to claim 62 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

71. A device according to claim 62 wherein said device is a liquid crystal display device.

72. A device according to claim 62 further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

120. A device according to claim 62 further comprising a second thin film transistor over the substrate, wherein the second thin film transistor has a second semiconductor layer having second source, channel, and drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said thin film transistor.

73. An electric device having an active matrix display device comprising:

a semiconductor island comprising silicon formed over a substrate having an insulating surface, said semiconductor island having a at least channel, source, and drain regions;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions through a first contact hole of said interlayer insulating film;

a planarizing film formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer through a second contact hole of said planarizing film,

wherein said second contact hole does not overlap said first contact hole.

74. A device according to claim 73 further comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

75. A device according to claim 73 wherein said gate electrode is located over said channel region.

76. A device according to claim 73 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

77. A device according to claim 73, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

78. A device according to claim 73 wherein said interlayer insulating film comprises silicon oxide.

79. A device according to claim 73 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

80. A device according to claim 73 wherein said conductive layer comprises aluminum.

81. A device according to claim 73 wherein said planarizing film comprises polyimide.

82. A device according to claim 73 wherein said pixel electrode is transparent.

83. A device according to claim 73 wherein said active matrix display device has a liquid crystal display device.

84. A device according to claim 73 wherein said electric device is a video camera.

112. A device according to claim 73 further comprising at least one offset region in said semiconductor island.

121. A device according to claim 74 further comprising a second semiconductor island over said substrate, said second semiconductor island having second source, channel, and drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said semiconductor island.

85. An electric device having an active matrix display device comprising:

a semiconductor layer formed over a substrate having an insulating surface, said semiconductor layer comprising source and drain regions including an impurity having one conductivity type at a first concentration, a channel region formed between said source and drain regions, and at least one lightly doped drain region formed between one of said source and drain regions and said channel region, wherein said lightly doped drain region includes said impurity at a second concentration lower than said first concentration;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and said gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions;

a planarizing film comprising an organic resin formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer.

86. A device according to claim 85 further comprising at least a lightly doped drain region formed between said source and drain regions and said channel region, wherein said lightly doped drain region includes an impurity having the same conductivity type as the source and drain regions at a lower concentration.

87. A device according to claim 85 wherein said gate electrode is located over said channel region.

88. A device according to claim 85, further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

89. A device according to claim 85 wherein said interlayer insulating film comprises silicon oxide.

91. A device according to claim 85 wherein said conductive layer comprises aluminum.

92. A device according to claim 85 wherein said planarizing film comprises polyimide.

93. A device according to claim 85 wherein said pixel electrode is transparent.

94. A device according to claim 85 wherein said active matrix display device has a liquid crystal display device.

95. A device according to claim 85 wherein said electric device is a video camera.

113. A device according to claim 85 further comprising at least one offset region in said semiconductor island.

122. A device according to claim 85 further comprising a second semiconductor island over said substrate, said second semiconductor island having second source, channel, and drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said semiconductor island.

96. An electric device having an active matrix display comprising:

a semiconductor layer formed over a substrate having an insulating surface, said semiconductor layer comprising source and drain regions including an impurity having one conductivity type at a first concentration, a channel region formed between said source and drain regions, and at least one lightly doped drain region formed between one of said source and drain regions and said channel region, wherein said lightly doped drain region includes said impurity at a second concentration lower than said first concentration;

a gate electrode adjacent to said channel region with a gate insulating film interposed therebetween;

an interlayer insulating film covering said semiconductor island and gate electrode;

a conductive layer formed on said interlayer insulating film and connected to one of the source and drain regions;

a planarizing film comprising an organic resin formed over said interlayer insulating film and said conductive layer; and

a pixel electrode formed over said planarizing film and connected to said conductive layer.

90. A device according to claim 96 wherein said interlayer insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

97. A device according to claim 96 wherein said semiconductor island has a hole mobility not lower than 10 cm²/Vsec or an electron mobility not lower than 15 cm²/Vsec.

98. A device according to claim 96 wherein said gate electrode comprises a material selected from the group consisting of Ti, Al, Ta, Cr and Si.

99. A device according to claim 96 wherein said gate electrode is located over said channel region.

100. A device according to claim 96 further comprising an anodic oxide film of said gate electrode in contact with said gate electrode.

101. A device according to claim 96 wherein said interlayer insulating film comprises silicon oxide.

102. A device according to claim 96 wherein said insulating film has a thickness within a range from 0.2 to 0.6 μ

m.

103. A device according to claim 96 wherein said conductive layer comprises aluminum.

104. A device according to claim 96 wherein said planarizing film comprises polyimide.

105. A device according to claim 96 wherein said pixel electrode is transparent.

106. A device according to claim 96 wherein said active matrix display device is a liquid crystal display device.

107. A device according to claim 96 wherein said electric device is a video camera.

123. A device according to claim 96 further comprising a second semiconductor layer over said substrate, said second semiconductor layer having second source, channel, and drain regions, and wherein the second source and drain regions include an impurity having one conductivity type opposite to said source and drain regions of said semiconductor layer.