Process for producing a photoelectric conversion device

• US 7,736,960 B2
• Filed: 03/23/2007
• Issued: 06/15/2010
• Est. Priority Date: 01/30/2001
• 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): Booth; Richard A.
• Application Number:
  US11/727,032
• Publication Number:
  US 20070166959A1
• Time in Patent Office: 1,180 Days
• Field of Search: 438151-166, 438/98, 257/E21.561
• US Class Current: 438/166
• CPC Class Codes: C30B 1/023 from solids with amorphous structure
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02425 Conductive materials, e.g. metallic silicides
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/3226 of silicon on insulator
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/072 the potential barriers being only of the PN heterojunction type
• CPC Class Codes: H01L 31/1804 comprising only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: H01L 31/208 Particular post-treatment of the devices, e.g. annealing, short-circuit elimination
• 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 catalyst element remaining in a first semiconductor film subjected to a first heat treatment (crystallization) is moved and concentrated/collected by subjecting a second semiconductor film which is formed on the first semiconductor film and contains a rare gas element to a second heat treatment. That is, the rare gas element is incorporated into the second semiconductor film to generate a strain field as a gettering site.

Claims

1. A process for producing a photoelectric conversion device, comprising:

forming a first semiconductor film having an amorphous structure including boron;

adding an element for promoting crystallization to the first semiconductor film having the amorphous structure;

conducting a first heat treatment to form a first semiconductor film having a crystal structure;

forming a second semiconductor film containing a rare gas element over the first semiconductor film having the crystal structure;

conducting a second heat treatment to segregate the element for promoting crystallization into the second semiconductor film;

removing the second semiconductor film;

forming an n-type crystalline silicon film over the first semiconductor film;

forming a transparent electrode over the n-type crystalline silicon film;

removing a part of the transparent electrode, a part of the n-type crystalline silicon film, and a part of the first semiconductor film having the crystal structure to expose the first semiconductor film having the crystal structure; and

forming a positive electrode onto the first semiconductor film having the crystal structure and a negative electrode onto the transparent electrode,

wherein the second heat treatment is conducted by rapid thermal annealing.

2. The process according to claim 1, wherein the second semiconductor film is formed by sputtering.

3. The process according to claim 1, wherein the second semiconductor film is formed by plasma CVD.

4. The process according to claim 1, wherein the first heat treatment is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

5. The process according to claim 1, wherein the first heat treatment is conducted by furnace annealing using an electrical heating furnace.

6. The process according to claim 1, wherein the rapid thermal annealing is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

7. The process according to claim 1, wherein the second heat treatment is conducted up to 1000°

C.

8. The process according to claim 1, wherein the rare gas element is one or more selected from He, Ne, Ar, Kr and Xe.

9. The process according to claim 1, wherein the element for promoting crystallization is one or more selected from Fe, Ni, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu and Au.

45. The process according to claim 1, wherein the rapid thermal annealing is performed by using a lamp.

50. The process according to claim 1, wherein the transparent electrode is made of an indium tin oxide alloy.

51. The process according to claim 1, wherein the transparent electrode is formed by sputtering.

52. The process according to claim 1, wherein the positive electrode and the negative electrode are formed of aluminum or silver.

53. The process according to claim 1, wherein the positive electrode and the negative electrode are formed by sputtering or vacuum evaporation.

10. A process for producing a photoelectric conversion device, comprising:

forming a first semiconductor film having an amorphous structure including boron;

adding an element for promoting crystallization to the first semiconductor film having the amorphous structure;

conducting a first heat treatment to form a first semiconductor film having a crystal structure;

forming a barrier layer over a surface of the first semiconductor film having the crystal structure;

forming a second semiconductor film containing a rare gas element over the barrier layer,

conducting a second heat treatment to segregate the element for promoting crystallization into the second semiconductor film,

removing the second semiconductor film;

forming an n-type crystalline silicon film over the first semiconductor film;

forming a transparent electrode over the n-type crystalline silicon film;

removing a part of the transparent electrode, a part of the n-type crystalline silicon film, and a part of the first semiconductor film having the crystal structure to expose the first semiconductor film having the crystal structure; and

forming a positive electrode onto the first semiconductor film having the crystal structure and a negative electrode onto the transparent electrode,

wherein the second heat treatment is conducted by rapid thermal annealing.

11. The process according to claim 10, wherein the second semiconductor film is formed by sputtering.

12. The process according to claim 10, wherein the second semiconductor film is formed by plasma CVD.

13. The process according to claim 10, wherein the barrier layer comprises a chemical oxide film formed using ozone water.

14. The process according to claim 10, wherein the barrier layer is formed by oxidizing the surface of the first semiconductor film having the crystal structure by plasma treatment.

15. The process according to claim 10, wherein the barrier layer is formed by oxidizing the surface of the first semiconductor film having the crystal structure with ozone generated by radiation of ultraviolet rays in an atmosphere containing oxygen.

16. The process according to claim 10, wherein the first heat treatment is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

17. The process according to claim 10, wherein the first heat treatment is conducted by furnace annealing using an electrical heating furnace.

18. The process according to claim 10, wherein the rapid thermal annealing is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

19. The process according to claim 10, wherein the second heat treatment is conducted up to 1000°

C.

20. The process according to claim 10, wherein the rare gas element is one or more selected from He, Ne, Ar, Kr and Xe.

21. The process according to claim 10, wherein the element for promoting crystallization is one or more selected from Fe, Ni, Go, Ru, Rh, Pd, Os, Ir, Pt, Cu and Au.

46. The process according to claim 10, wherein the rapid thermal annealing is performed by using a lamp.

54. The process according to claim 10, wherein the transparent electrode is made of an indium tin oxide alloy.

55. The process according to claim 10, wherein the transparent electrode is formed by sputtering.

56. The process according to claim 10, wherein the positive electrode and the negative electrode are formed of aluminum or silver.

57. The process according to claim 10, wherein the positive electrode and the negative electrode are formed by sputtering or vacuum evaporation.

22. A process for producing a photoelectric conversion device, comprising:

forming a first semiconductor film having an amorphous structure including boron;

adding an element for promoting crystallization to the first semiconductor film having the amorphous structure;

conducting a first heat treatment to form a first semiconductor film having a crystal structure;

forming a second semiconductor film over the first semiconductor film having the crystal structure;

adding a rare gas element to the second semiconductor film;

conducting a second heat treatment to segregate the element for promoting crystallization into the second semiconductor film,

removing the second semiconductor film;

forming an n-type crystalline silicon film over the first semiconductor film;

forming a transparent electrode over the n-type crystalline silicon film;

removing a part of the transparent electrode, a part of the n-type crystalline silicon film, and a part of the first semiconductor film having the crystal structure to expose the first semiconductor film having the crystal structure; and

forming a positive electrode onto the first semiconductor film having the crystal structure and a negative electrode onto the transparent electrode,

wherein the second heat treatment is conducted by rapid thermal annealing.

23. The process according to claim 22, wherein the rare gas element is added by any one of ion implantation and ion doping.

24. The process according to claim 22, wherein the first heat treatment is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

25. The process according to claim 22, wherein the first heat treatment is conducted by furnace annealing using an electrical heating furnace.

26. The process according to claim 22, wherein the rapid thermal annealing is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

27. The process according to claim 22, wherein the second heat treatment is conducted up to 1000°

C.

28. The process according to claim 22, wherein the rare gas element is one or more selected from He, Ne, Ar, Kr and Xe.

29. The process according to claim 22, wherein the element for promoting crystallization is one or more selected from Fe, Ni, Go, Ru, Rh, Pd, Os, Ir, Pt, Cu and Au.

47. The process according to claim 22, wherein the rapid thermal annealing is performed by using a lamp.

58. The process according to claim 22, wherein the transparent electrode is made of an indium tin oxide alloy.

59. The process according to claim 22, wherein the transparent electrode is formed by sputtering.

60. The process according to claim 22, wherein the positive electrode and the negative electrode are formed of aluminum or silver.

61. The process according to claim 22, wherein the positive electrode and the negative electrode are formed by sputtering or vacuum evaporation.

30. A process for producing a photoelectric conversion device, comprising:

forming a first semiconductor film having an amorphous structure including boron;

adding an element for promoting crystallization to the first semiconductor film having the amorphous structure;

conducting a first heat treatment to form a first semiconductor film having a crystal structure;

forming a barrier layer over a surface of the first semiconductor film having the crystal structure;

forming a second semiconductor film over the barrier layer;

adding a rare gas element to the second semiconductor film;

conducting a second heat treatment to segregate the element for promoting crystallization into the second semiconductor film;

removing the second semiconductor film;

forming an n-type crystalline silicon film over the first semiconductor film;

forming a transparent electrode over the n-type crystalline silicon film;

removing a part of the transparent electrode, a part of the n-type crystalline silicon film, and a part of the first semiconductor film having the crystal structure to expose the first semiconductor film having the crystal structure; and

forming a positive electrode onto the first semiconductor film having the crystal structure and a negative electrode onto the transparent electrode,

wherein the second heat treatment is conducted by rapid thermal annealing.

31. The process according to claim 30, wherein the rare gas element is added by any one of ion implantation and ion doping.

32. The process according to claim 30, wherein the barrier layer comprises a chemical oxide film formed using ozone water.

33. The process according to claim 30, wherein the barrier layer is formed by oxidizing the surface of the first semiconductor film having the crystal structure by plasma treatment.

34. The process according to claim 30, wherein the barrier layer is formed by oxidizing the surface of the first semiconductor film having the crystal structure with ozone generated by radiation of ultraviolet rays in an atmosphere containing oxygen.

35. The process according to claim 30, wherein the first heat treatment is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

36. The process according to claim 30, wherein the first heat treatment is conducted by furnace annealing using an electrical heating furnace.

37. The process according to claim 30, wherein the rapid thermal annealing is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

38. The process according to claim 30, wherein the second heat treatment is conducted up to 1000°

C.

39. The process according to claim 30, wherein the rare gas element is one or more selected from He, Ne, Ar, Kr and Xe

40. The process according to claim 30, wherein the element for promoting crystallization is one or more selected from Fe, Ni, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu and Au.

48. The process according to claim 30, wherein the rapid thermal annealing is performed by using a lamp.

62. The process according to claim 30, wherein the transparent electrode is made of an indium tin oxide alloy.

63. The process according to claim 30, wherein the transparent electrode is formed by sputtering.

64. The process according to claim 30, wherein the positive electrode and the negative electrode are formed of aluminum or silver.

65. The process according to claim 30, wherein the positive electrode and the negative electrode are formed by sputtering or vacuum evaporation.

41. A process for producing a photoelectric conversion device, comprising:

forming a first semiconductor film having an amorphous structure including boron;

adding an element for promoting crystallization to the first semiconductor film having the amorphous structure;

conducting a first heat treatment to form a first semiconductor film having a crystal structure;

forming a second semiconductor film over the first semiconductor film having the crystal structure, wherein a rare gas element is added to the second semiconductor film;

conducting a second heat treatment to segregate the element for promoting crystallization into the second semiconductor film;

removing the second semiconductor film;

forming an n-type crystalline silicon film over the first semiconductor film;

forming a transparent electrode over the n-type crystalline silicon film;

removing a part of the transparent electrode, a part of the n-type crystalline silicon film, and a part of the first semiconductor film having the crystal structure to expose the first semiconductor film having the crystal structure; and

forming a positive electrode onto the first semiconductor film having the crystal structure and a negative electrode onto the transparent electrode,

wherein the second heat treatment is conducted by rapid thermal annealing.

42. The process according to claim 41, further comprising forming a barrier layer over a surface of the first semiconductor film having the crystal structure.

43. The process according to claim 41, wherein the rapid thermal annealing is conducted by radiation from one or more selected from a halogen lamp, a metal halide lamp, a xenon arc lamp, a carbon arc lamp, a high-pressure sodium lamp, or a high-pressure mercury lamp.

44. The process according to claim 41, wherein the second heat treatment is conducted up to 1000°

C.

49. The process according to claim 41, wherein the rapid thermal annealing is performed by using a lamp.

66. The process according to claim 41, wherein the transparent electrode is made of an indium tin oxide alloy.

67. The process according to claim 41, wherein the transparent electrode is formed by sputtering.

68. The process according to claim 41, wherein the positive electrode and the negative electrode are formed of aluminum or silver.

69. The process according to claim 41, wherein the positive electrode and the negative electrode are formed by sputtering or vacuum evaporation.