Thin-film photoelectric conversion device and a method of manufacturing the same

• US 7,075,002 B1
• Filed: 08/06/1997
• Issued: 07/11/2006
• Est. Priority Date: 03/27/1995
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Arai, Yasuyuki, Yamazaki, Shunpei
• Primary Examiner(s): DIAMOND, ALAN D
• Application Number:
  US08/907,182
• Time in Patent Office: 3,261 Days
• Field of Search: 136/258.PC, 136/261, 136/258, 257/49, 257/75, 438/476, 438/486, 438/58, 438/97, 438/152, 438/153, 438/151, 438/150, 438/149, 438/147, 438/142
• US Class Current: 136/258
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/0682 back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/186 Particular post-treatment for the devices, e.g. annealing, impurity gettering, short-circuit elimination, recrystallisation
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method of manufacturing a thin-film solar cell, comprising the steps of: forming an amorphous silicon film on a substrate; placing a metal element that accelerates the crystallization of silicon in contact with the surface of the amorphous silicon film; subjecting the amorphous silicon film to a heat treatment to obtain a crystalline silicon film; depositing a silicon film to which phosphorus has been added in contact with the crystalline silicon film; and subjecting the crystalline silicon film and the silicon film to which phosphorus has been added to a heat treatment to getter the metal element from the crystalline film.

Claims

1. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film on an insulating surface;

providing said semiconductor film with a catalyst metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said catalyst metal to diffuse through the semiconductor film and function to promote the crystallization of the semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization; and

heating said semiconductor film and said gettering layer in order to getter the catalyst metal in said semiconductor film using said gettering layer.

2. A method according to claim 1 wherein said semiconductor device is a photoelectric conversion device.

3. A method according to claim 1 wherein said heating to getter the catalyst metal is continued for 1–

4 hours.

4. A method according to claim 1 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

5. A method according to claim 1 wherein said catalyst metal is selected from the group consisting of Ni, Fe, Co, and Pt.

6. A method according to claim 1 further comprising a step of removing said gettering layer after the gettering.

54. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42 or 45–

53 wherein said insulating surface comprises silicon oxide.

55. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42 or 45–

53 wherein the concentration of said metal in said crystallized semiconductor film is not higher than 5×

10 atoms/cm³.

56. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42, 45, 49, or 53 wherein said semiconductor film is provided by a plasma CVD technique.

57. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42, 45, 49, or 53 wherein said semiconductor film is provided by a low pressure CVD technique.

58. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42, 45, 49, or 53 wherein said semiconductor film is provided by a sputtering technique.

63. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42, 46, or 50 wherein said gettering layer is formed by a CVD technique.

66. A method according to any one of claims 1, 7, 14, 22, 28, 35, 42, 46, or 50, wherein said gettering layer is in contact with said semiconductor film.

7. A method of manufacturing a semiconductor device comprising:

providing a substantially intrinsic semiconductor film on an insulating surface;

providing said semiconductor film with a catalyst metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said catalyst metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization; and

heating said semiconductor film and said gettering layer in order to getter the catalyst metal in said semiconductor film by said gettering layer.

8. A method according to claim 7 wherein said semiconductor device is a photoelectric conversion device.

9. A method according to claim 7 wherein said heating to getter the catalyst metal is continued for 1–

4 hours.

10. A method according to claim 7 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

11. A method according to claim 7 wherein said catalyst metal is selected from the group consisting of Ni, Fe, Co, and Pt.

12. A method according to claim 7 further comprising a step of removing said gettering layer after the gettering.

13. A method according to claim 7 wherein said heating to getter the catalyst metal is conducted within a temperature from 500°

C. to 800°

C.

14. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film on an insulating surface;

providing a catalyst metal-containing material on said semiconductor film;

crystallizing said semiconductor film by heating in a way that causes said catalyst metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization; and

heating said semiconductor film and said gettering layer in a nitrogen atmosphere in order to getter the catalyst metal contained in said semiconductor film by said gettering layer.

15. A method according to claim 14 wherein said semiconductor device is a photoelectric conversion device.

16. A method according to claim 14 wherein said heating to getter the catalyst metal is conducted for 1–

4 hours.

17. A method according to claim 14 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

18. A method according to claim 14 wherein said semiconductor film comprises silicon.

19. A method according to claim 14 wherein said catalyst metal is selected from the group consisting of Ni, Fe, Co, and Pt.

20. A method according to claim 14 further comprising a step of removing said gettering layer after the gettering.

21. A method according to claim 14 wherein said heating to getter the catalyst metal is conducted within a temperature from 500°

C. to 800°

C.

22. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a semiconductor film comprising amorphous silicon on an insulating surface;

providing a catalyst metal-containing material on said semiconductor film;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and to promote the crystallization thereof;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization;

heating said semiconductor film and said gettering layer at a temperature from 500°

C. to 800°

C. in order to getter the metal included in said semiconductor film by said gettering layer; and

forming a doped semiconductor film on said semiconductor film to form a junction.

23. A method according to claim 22 wherein said semiconductor device is a photoelectric conversion device.

24. A method according to claim 22 wherein said heating to getter the metal is conducted for 1–

4 hours.

25. A method according to claim 22 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

26. A method according to claim 22 wherein said catalyst metal is selected from the group consisting of Ni, Fe, Co, and Pt.

27. A method according to claim 22 further comprising a step of removing said gettering layer after the gettering.

28. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a substantially intrinsic semiconductor film on an insulating surface;

providing a catalyst metal on said semiconductor film;

crystallizing said semiconductor film by heating to cause said catalyst metal to diffuse through the semiconductor film and to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization thereof;

heating said semiconductor film and said gettering layer in order to getter the catalyst metal in said semiconductor film by said gettering layer; and

forming a junction using said intrinsic semiconductor film.

29. A method according to claim 28 wherein said semiconductor device is a photoelectric conversion device.

30. A method according to claim 28 wherein said heating to getter the catalyst metal is continued for 1–

4 hours.

31. A method according to claim 28 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

32. A method according to claim 28 wherein said catalyst metal is selected from the group consisting of Ni, Fe, Co, and Pt.

33. A method according to claim 28 further comprising a step of removing said gettering layer after the gettering.

34. A method according to claim 28 wherein said heating to getter the catalyst metal is conducted within a temperature from 500°

C. to 800°

C.

35. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a semiconductor film comprising amorphous silicon formed on an insulating surface;

providing a catalyst metal-containing material on said semiconductor film;

crystallizing said semiconductor film by heating in a way that causes said catalyst metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization; and

heating said semiconductor film and said gettering layer in a nitrogen atmosphere in order to getter the catalyst metal contained in said semiconductor film by said gettering layer; and

forming a junction on said semiconductor film.

36. A method according to claim 35 wherein said semiconductor device is a photoelectric conversion device.

37. A method according to claim 35 wherein said heating to getter the catalyst metal is continued for 1–

4 hours.

38. A method according to claim 35 wherein said phosphorus silicate glass contains phosphorus at a concentration of 1 to 30 wt %.

39. A method according to claim 35 wherein said catalyst metal is selected form the group consisting of Ni, Fe, Co, and Pt.

40. A method according to claim 35 further comprising a step of removing said gettering layer after the gettering.

41. A method according to claim 35 wherein said heating to getter the catalyst metal is conducted within a temperature from 500°

C. to 800°

C.

42. A method of manufacturing a semiconductor device, comprising:

providing a semiconductor film on an insulating surface;

forming a catalyst metal-containing material on said semiconductor film, said catalyst being a material which facilitates crystallization of said semiconductor film, but which when present in a final product of the semiconductor device degrades operation of the semiconductor device;

crystallizing said semiconductor film by heating in a way that causes said catalyst metal-containing material to diffuse into at least a part of the semiconductor film, said catalyst metal-containing material when so diffused functioning to facilitate said crystallization;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after said crystallization; and

processing said semiconductor film and said gettering layer to reduce the concentration of said catalyst metal in said semiconductor film.

43. A method as in claim 42, wherein said metal includes Nickel.

44. A method as in claim 42, wherein the catalyst material allows said crystallization to occur at a lower temperature.

45. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film on an insulating surface;

providing said semiconductor film with a metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and function to promote the crystallization of the semiconductor film;

introducing a gettering material into a surface of said crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film after introducing said gettering material in order to getter the metal in said semiconductor film; and

removing at least said surface after gettering the metal in said semiconductor film.

60. A method according to any one of claims 45–

53 wherein said semiconductor device is a photoelectric conversion device.

61. A method according to any one of claims 45–

53 wherein said heating or processing to getter the metal is conducted for 1–

4 hours.

62. A method according to any one of claims 45–

53 wherein said metal is selected from the group consisting of Ni, Fe, Co, and Pt.

64. A method according to any one of claims 45, 47–

49, or 51–

53, wherein said gettering material comprises phosphorus.

65. A method according to any one of claims 45, 47–

49, or 51–

53, wherein said gettering material is introduced by a plasma doping method.

67. A method according to any one of claims 45, 47–

49, or 51–

53, wherein said gettering material is introduced into an entire surface of the crystallized semiconductor film.

46. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film doped with boron at a concentration of 0.001–

0.1 atm % on an insulating surface;

providing said semiconductor film with a metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization; and

heating said semiconductor film and said gettering layer in order to getter the metal in said semiconductor film by said gettering layer.

59. A method according to any one of claims 46–

53 wherein said heating or processing to getter the metal is conducted within a temperature from 500°

C. to 800°

C.

47. A method of manufacturing a semiconductor device comprising:

providing a substantially intrinsic semiconductor film on an insulating surface;

providing said semiconductor film with a metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film after introducing said gettering material in order to getter the metal in said semiconductor film; and

removing at least said surface after gettering the metal in said semiconductor film.

48. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film doped with boron at a concentration of 0.001–

0.1 atm % on an insulating surface;

providing said semiconductor film with a metal-containing material;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film after introducing said gettering material in order to getter the metal in said semiconductor film; and

removing at least said surface after gettering the metal in said semiconductor film.

49. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film on an insulating surface;

providing a metal-containing material on said semiconductor film;

crystallizing said semiconductor film by heating in a way that causes said metal to diffuse through the semiconductor film and function to promote the crystallization of said semiconductor film;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film in a nitrogen atmosphere after introducing said gettering material in order to getter the metal contained in said semiconductor film; and

removing at least said surface after gettering the metal in said semiconductor film.

50. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a semiconductor film doped with boron at a concentration of 0.001–

0.1 atm % on an insulating surface;

providing a metal on said semiconductor film;

crystallizing said semiconductor film by heating to cause said metal to diffuse through the semiconductor film and to promote the crystallization of said semiconductor film;

forming a gettering layer comprising phosphorus silicate glass over an entire surface of said semiconductor film after the crystallization thereof, heating said semiconductor film and said gettering layer in order to getter the metal in said semiconductor film by said gettering layer; and

forming a junction using an intrinsic semiconductor film.

51. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a substantially intrinsic semiconductor film on an insulating surface;

providing a metal on said semiconductor film;

crystallizing said semiconductor film by heating to cause said metal to diffuse through the semiconductor film and to promote the crystallization of said semiconductor film;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film after introducing said gettering material in order to getter the metal in said semiconductor film by said phosphorus;

removing at least said surface after gettering the metal in said semiconductor film; and

forming a junction using a doped semiconductor film.

52. A method of manufacturing a semiconductor device having a junction, said method comprising:

providing a semiconductor film doped with boron at a concentration of 0.001–

0.1 atm % on an insulating surface;

providing a metal on said semiconductor film;

crystallizing said semiconductor film by heating to cause said metal to diffuse through the semiconductor film and to promote the crystallization of said semiconductor film;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

heating said semiconductor film and said gettering material in order to getter the metal in said semiconductor film;

removing at least said surface after gettering the metal in said semiconductor film; and

forming a junction using an intrinsic semiconductor film.

53. A method of manufacturing a semiconductor device comprising:

providing a semiconductor film on an insulating surface;

forming a metal-containing material on said semiconductor film, said metal being a material which facilitates crystallization of said semiconductor film, but which when present in a final product of the semiconductor device degrades operation of the semiconductor device;

crystallizing said semiconductor film by heating in a way that causes said metal-containing material to diffuse into at least a part of the semiconductor film, said metal-containing material when so diffused functioning to facilitate said crystallization;

introducing a gettering material into a surface of the crystallized semiconductor film within a region of 0.1 to 0.2 μ

m in depth from the surface of the crystallized semiconductor film;

processing said semiconductor film after introducing said gettering material to reduce the concentration of said metal in said semiconductor film; and

removing at least said surface of the crystallized semiconductor film after gettering the metal in said semiconductor film.