Semiconductor device and fabrication method thereof

• US 7,365,393 B2
• Filed: 09/21/2004
• Issued: 04/29/2008
• Est. Priority Date: 02/23/1999
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohnumo, Hideto, Murakami, Satoshi, Koyama, Jun, Yamazaki, Shunpei, Kitakado, Hidehito, Tanaka, Yukio
• Primary Examiner(s): Dickey; Thomas L.
• Application Number:
  US10/945,048
• Publication Number:
  US 20050040401A1
• Time in Patent Office: 1,316 Days
• Field of Search: 257/59, 257/66, 257/344, 349 38- 44
• US Class Current: 257/344
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G02F 2202/104 poly-Si
• CPC Class Codes: H01L 2029/7863 with an LDD consisting of more than one lightly doped zone or having a non-homogeneous dopant distribution, e.g. graded LDD
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/124 : Insulating layers formed between TFT elements and OLED elements
• CPC Class Codes: H10K 59/126 : Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 59/131 : Interconnections, e.g. wiring lines or terminals

Abstract

This invention provides a semiconductor device having high operation performance and high reliability. An LDD region 707 overlapping with a gate wiring is arranged in an n-channel TFT 802 forming a driving circuit, and a TFT structure highly resistant to hot carrier injection is achieved. LDD regions 717, 718, 719 and 720 not overlapping with a gate wiring are arranged in an n-channel TFT 804 forming a pixel unit. As a result, a TFT structure having a small OFF current value is achieved. In this instance, an element belonging to the Group 15 of the Periodic Table exists in a higher concentration in the LDD region 707 than in the LDD regions 717, 718, 719 and 720.

Claims

1. A portable information terminal comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

2. A semiconductor device according to claim 1, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

3. A portable information terminal according to claim 1, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

4. A portable information terminal according to claim 1, wherein the portable information terminal is one of a mobile computer, a cellular telephone, a portable game machine, or an electronic book.

5. A portable information terminal comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

6. A semiconductor device according to claim 5, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

7. A portable information terminal according to claim 5, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

8. A portable information terminal according to claim 5, wherein the portable information terminal is one of a mobile computer, a cellular telephone, a portable game machine, or an electronic book.

9. A portable information terminal according to claim 5, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

10. A portable information terminal according to claim 5, wherein the oxide is a film comprising an aluminum oxide.

11. A portable information terminal comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

12. A semiconductor device according to claim 11, wherein each of said first, second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

13. A portable information terminal according to claim 11, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

14. A portable information terminal according to claim 11, wherein the portable information terminal is one of a mobile computer, a cellular telephone, a portable game machine, or an electronic book.

15. A portable information terminal comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

16. A semiconductor device according to claim 15, wherein each of said first, second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

17. A portable information terminal according to claim 15, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

18. A portable information terminal according to claim 15, wherein the portable information terminal is one of a mobile computer, a cellular telephone, a portable game machine, or an electronic book.

19. A portable information terminal according to claim 15, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

20. A portable information terminal according to claim 15, wherein the oxide is a film comprising an aluminum oxide.

21. A computer comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

22. A computer according to claim 21, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

23. A computer according to claim 21, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

24. A computer comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

25. A computer according to claim 24, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

26. A computer according to claim 24, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

27. A computer according to claim 24, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

28. A computer according to claim 24, wherein the oxide is a film comprising an aluminum oxide.

29. A computer comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

30. A computer according to claim 29, wherein each of said first second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

31. A computer according to claim 29, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

32. A computer comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

33. A computer according to claim 32, wherein each of said first,

second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

34. A computer according to claim 32, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

35. A computer according to claim 32, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

36. A computer according to claim 32, wherein the oxide is a film comprising an aluminum oxide.

37. A camera comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first-gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

38. A camera according to claim 37, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

39. A camera according to claim 37, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

40. A camera comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the second semiconductor layer comprises a second LDD region not overlapped with the second gate electrode with the gate insulating film interposed therebetween.

41. A camera according to claim 40, wherein each of the first and second LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of the impurity element in the first LDD region is higher than in the second LDD region.

42. A camera according to claim 40, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

43. A camera according to claim 40, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

44. A camera according to claim 40, wherein the oxide is a film comprising an aluminum oxide.

45. A camera comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

46. A camera according to claim 45, wherein each of said first second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

47. A camera according to claim 45, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

48. A camera comprising:

a display device, the display device comprising a driving circuit and a pixel portion formed over a substrate,

the driving circuit comprising;

a first thin film transistor comprising a first semiconductor layer and a first gate electrode adjacent to the first semiconductor layer with a gate insulating film interposed therebetween; and

a second thin film transistor comprising a second semiconductor layer and a second gate electrode adjacent to the second semiconductor layer with the gate insulating film interposed therebetween,

wherein the first semiconductor layer comprises a first LDD region wholly overlapped with the first gate electrode with the gate insulating film interposed therebetween, and

wherein the second semiconductor layer comprises a second LDD region partly overlapped with the second gate electrode with the gate insulating film interposed therebetween,

the pixel portion comprising;

a third thin film transistor comprising a third semiconductor layer and a third gate electrode adjacent to the third semiconductor layer with the gate insulating film interposed therebetween; and

a capacitor comprising a shading film disposed on a resin film, an oxide of the shading film, and a pixel electrode disposed on the oxide,

wherein the third semiconductor layer comprises a third LDD region not overlapped with the third gate electrode with the gate insulating film interposed therebetween.

49. A camera according to claim 48, wherein each of said first second and third LDD regions contains an impurity element belonging to the Group 15 of the Periodic Table, and a concentration of said impurity element in each of said first and second LDD regions is higher than in said third LDD region.

50. A camera according to claim 48, wherein at least one of the first and second gate electrodes has a first layer comprising tantalum nitride and a second layer comprising tungsten on the first layer.

51. A camera according to claim 48, wherein the shading film comprises an aluminum film or a film consisting of aluminum as the principal component.

52. A camera according to claim 48, wherein the oxide is a film comprising an aluminum oxide.