Semiconductor device and method of fabricating the same
View Patent ↗To provide a thin film transistor having a high field effect mobility and a small variation in characteristics thereof, a second amorphous semiconductor layer patterned in a predetermined shape is formed on a first crystalline semiconductor layer 17 for constituting source and drain regions. By irradiating an irradiated region 21 of continuous wave laser beam while scanning along a channel length direction, the second amorphous semiconductor layer is crystallized to form a second crystalline semiconductor layer 22 . The first crystalline semiconductor layer 17 is crystallized by selectively adding nickel and therefore, an orientation rate of {111} is increased. By irradiating laser beam, crystals of the second amorphous semiconductor layer grow by constituting a seed by the first crystalline semiconductor layer 17 oriented to {111} and therefore, a region 22 a for constituting a channel forming region is also oriented highly to {111} and a direction of a crystal grain boundary becomes parallel with the channel length direction.
1. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein in crystallizing the patterned second amorphous semiconductor layer, an irradiated region of a continuous wave laser beam is moved from the first region to the second region;
wherein the first region is used as at least one of a source region and a drain region of a thin film transistor;
wherein the second region is used as a channel forming region of the thin film transistor, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
2. The method according to claim 1 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
3. The method according to claim 1 ,
wherein the continuous wave laser beam is a laser beam having a wavelength of 400 nm through 700 nm.
4. The method according to claim 1 ,
wherein the continuous wave laser beam is a harmonic of a laser beam excited by a solid state laser oscillating apparatus.
5. The method according to claim 1 ,
wherein the first amorphous semiconductor layer is a silicon layer, a germanium layer or a silicon germanium (Si x Ge 1-x 0<x<1) layer.
6. The method according to claim 1 ,
wherein the first amorphous semiconductor layer is a layer whose major component is silicon in which a content of germanium falls in a range of 1 atomic % through 10 atomic %.
7. The method according to claim 1 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
8. The method according to claim 1 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
9. The method according to claim 1 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
10. The method according to claim 1 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
11. The method according to claim 1 ,
wherein the crystallization of the patterned second amorphous semiconductor layer is performed by irradiating a continuous wave laser beam to the patterned second amorphous semiconductor layer while moving the continuous wave laser beam relative to the substrate to form a second crystalline semiconductor layer.
12. The method according to claim 1 , wherein the channel forming region has a highest crystal orientation rate of {111} among crystal planes of {001}, {101} and {111} in a surface.
13. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein the first amorphous semiconductor layer comprises a layer whose major component is silicon including germanium,
wherein in crystallizing the patterned second amorphous semiconductor layer, an irradiated region of a continuous wave laser beam is moved from the first region to the second region;
wherein the first region is used as at least one of a source region and a drain region of a thin film transistor;
wherein the second region is used as a channel forming region of the thin film transistor, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
14. The method according to claim 13 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
15. The method according to claim 13 ,
wherein the continuous wave laser beam is a laser beam having a wavelength of 400 nm through 700 nm.
16. The method according to claim 13 ,
wherein the continuous wave laser beam is a harmonic of a laser beam excited by a solid state laser oscillating apparatus.
17. The method according to claim 13 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
18. The method according to claim 13 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
19. The method according to claim 13 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
20. The method according to claim 13 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
21. The method according to claim 13 ,
wherein the crystallization of the patterned second amorphous semiconductor layer is performed by irradiating a continuous wave laser beam to the patterned second amorphous semiconductor layer while moving the continuous wave laser beam relative to the substrate to form a second crystalline semiconductor layer.
22. The method according to claim 13 , wherein the channel forming region has a highest crystal orientation rate of {101} among crystal planes of {001}, {101} and {111} in a surface.
23. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein in crystallizing the second region of the patterned second amorphous semiconductor layer, a pulse laser beam is irradiated to both of the first region and the second region;
wherein the first region is used as at least one of a source region and a drain region of a thin film transistor;
wherein the second region is used as a channel forming region of the thin film transistor, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
24. The method according to claim 23 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
25. The method according to claim 23 ,
wherein the first amorphous semiconductor layer is a silicon layer, a germanium layer or a silicon germanium (Si x Ge 1-x 0<x<1) layer.
26. The method according to claim 23 ,
wherein the first amorphous semiconductor layer is a layer whose major component is silicon in which a content of germanium falls in a range of 1 atomic % through 10 atomic %.
27. The method according to claim 23 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
28. The method according to claim 23 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
29. The method according to claim 23 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
30. The method according to claim 23 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
31. The method according to claim 23 ,
wherein the crystallization of the patterned second amorphous semiconductor layer is performed by irradiating a pulse laser beam to the patterned second amorphous semiconductor layer while moving the pulse laser beam relative to the substrate to form a patterned second crystalline semiconductor layer.
32. The method according to claim 23 , wherein the channel forming region has a highest crystal orientation rate of {111} among crystal planes of {001}, {101} and {111} in a surface.
33. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein the first amorphous semiconductor layer comprises a layer whose major component is silicon including germanium;
wherein in crystallizing the second region of the patterned second amorphous semiconductor layer, a pulse laser beam is irradiated to both of the first region and the second region;
wherein the first region is used as at least one of a source region and a drain region of a thin film transistor;
wherein the second region is used as a channel forming region of the thin film transistor, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
34. The method according to claim 33 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
35. The method according to claim 33 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
36. The method according to claim 33 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
37. The method according to claim 33 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
38. The method according to claim 33 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
39. The method according to claim 33 ,
wherein the crystallization of the patterned second amorphous semiconductor layer is performed by irradiating a pulse laser beam to the patterned second amorphous semiconductor layer while moving the pulse laser beam relative to the substrate to form a patterned second crystalline semiconductor layer.
40. The method according to claim 33 , wherein the channel forming region has a highest crystal orientation rate of {101} among crystal planes of {001}, {101} and {111} in a surface.
41. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein the first region is used as at least one of a source region and a drain region;
wherein the second region is used as a channel forming region, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
42. The method according to claim 41 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
43. The method according to claim 41 ,
wherein the first amorphous semiconductor layer is a silicon layer, a germanium layer or a silicon germanium (Si x Ge 1-x 0<x<1) layer.
44. The method according to claim 41 ,
wherein the first amorphous semiconductor layer is a layer whose major component is silicon in which a content of germanium falls in a range of 1 atomic % through 10 atomic %.
45. The method according to claim 41 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
46. The method according to claim 41 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
47. The method according to claim 41 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
48. The method according to claim 41 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
49. The method according to claim 41 , wherein the channel forming region has a highest crystal orientation rate of {111} among crystal planes of {001}, {101} and {111} in a surface.
50. A method of manufacturing a semiconductor device comprising:
forming a first amorphous semiconductor layer over a substrate;
adding a metal element for reducing a crystallization energy of the semiconductor to a selected portion of the first amorphous semiconductor layer;
crystallizing the first amorphous semiconductor layer by a heating treatment to form a first crystalline semiconductor layer;
patterning the first crystalline semiconductor layer to form at least one patterned first crystalline semiconductor layer;
forming a second amorphous semiconductor layer on the patterned first crystalline semiconductor layer;
patterning the second amorphous semiconductor layer to form at least one patterned second amorphous semiconductor layer having a first region overlapped with the patterned first crystalline semiconductor layer and a second region which is not overlapped with the patterned first crystalline semiconductor layer; and
crystallizing the patterned second amorphous semiconductor layer,
wherein the first amorphous semiconductor layer comprises a layer whose major component is silicon including germanium;
wherein the first region is used as at least one of a source region and a drain region;
wherein the second region is used as a channel forming region, and
wherein the second amorphous semiconductor layer is thinner than the first amorphous semiconductor layer.
51. The method according to claim 50 ,
wherein a thickness of the second amorphous semiconductor layer falls in a range of 10 through 60 nm.
52. The method according to claim 50 ,
wherein the metal element comprises at least one selected from the group consisting of Pd, Pt, Ni, Cr, Fe, Co, Ti, V and Rh.
53. The method according to claim 50 , further comprising the step of carrying out a gettering processing of removing the metal element from the patterned first crystalline semiconductor layer.
54. The method according to claim 50 , wherein the semiconductor device is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a head-mount type display, a navigation system, a sound reproducing apparatus, a personal computer, a game machine, a portable information terminal, a portable telephone, a portable game machine and an electronic book.
55. The method according to claim 50 , further comprising a step of irradiating a laser beam selected from the group consisting of a continuous wave laser beam and a pulse laser beam to the first crystalline semiconductor layer after the heating treatment.
56. The method according to claim 50 , wherein the channel forming region has a highest crystal orientation rate of {101} among crystal planes of {001}, {101} and {111} in a surface.