Method and apparatus for forming deposited film

• US 5,571,749 A
• Filed: 12/28/1994
• Issued: 11/05/1996
• Est. Priority Date: 12/28/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsuda, Koichi, Miyamoto, Yusuke, Kondo, Takaharu
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/365,244
• Time in Patent Office: 678 Days
• Field of Search: 437/4, 437/101, 437/108-109, 437/113, 427/574-575, 427/578, 427/573, 118/718-719, 118/723 R, 118/723 MP, 118/723 MW, 118/723 E, 118/724-725, 136/258 AM
• US Class Current: 438/484
• CPC Class Codes: C23C 16/46 characterised by the method used for heating the substrate C23C16/48, C23C16/50 take precedence
• CPC Class Codes: C23C 16/463 Cooling of the substrate
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: C23C 16/545 for coating elongated substrates
• CPC Class Codes: H01L 21/02425 Conductive materials, e.g. metallic silicides
• CPC Class Codes: H01L 21/02447 Silicon carbide
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02452 including tin
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/02529 Silicon carbide
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02535 including tin
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• CPC Class Codes: H01L 31/076 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/206 Particular processes or apparatus for continuous treatment of the devices, e.g. roll-to roll processes, multi-chamber deposition
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A plasma CVD method adapted to a roll-to-roll process or the like wherein the change rate of the temperature of the substrate before and after an i-type semiconductor layer is deposited is made rapid so as to prevent diffusion of impurities occurring due to annealing, by constituting the apparatus structure in such a manner that the deposited film is formed on an elongated substrate by the plasma CVD method while heating the elongated substrate moving in an i-layer forming discharge chamber at a rate of 4° C./second or higher immediately in front of an inlet to the discharge chamber and cooling the same at a rate of 4° C./second or higher immediately at the outlet of the discharge chamber so that a stacked-layer type photovoltaic device having a large area and free from scattering of the characteristics is continuously formed without deterioration of the characteristics occurring due to dopant diffusion.

Claims

1. A process for forming a deposited semiconductor film by glow discharge on a continuously moving belt-like substrate which has a first semiconductor layer deposited thereon, which comprises the steps of:

heating said moving substrate immediately before said substrate enters a glow discharge region;

forming said deposited semiconductor film on said moving substrate in said glow discharge region; and

cooling said moving substrate after passing through said glow discharge region.

2. A process for forming a deposited film according to claim 1, further comprising a step of maintaining the temperature of said moving substrate in said glow discharge region.

3. A process for forming a deposited film according to claim 1, wherein said moving substrate is heated at a rate of 4°

C./second or higher.

4. A process for forming a deposited film according to claim 1, wherein said moving substrate is cooled at a rate of 4°

C./second or higher.

5. A process foe forming a deposited film according to claim 1, wherein said deposited film is deposited at a rate of 0.1 nm/second to 20 nm/second.

6. A process for forming a deposited film according to claim 1, wherein said glow discharge is caused by microwave plasma CVD.

7. A process for forming a deposited film according to claim 1, further comprising a step of forming a second semiconductor layer having a conductivity type different from said first semiconductor layer on said deposited film after said cooling step.

12. A process for forming a deposited film according to claim 1, wherein said belt-like substrate is cooled by a flowing cooling medium.

13. A process for forming a deposited film according to claim 1, wherein said deposited film formed by glow discharge is an i-type semiconductor.

14. A process for forming a deposited film according to claim 13, wherein a raw material gas for forming the i-type semiconductor layer comprises a gasifiable compound which contains silicon atoms.

15. A process for forming a deposited film according to claim 14, wherein the raw material gas further comprises a compound which contains carbon atoms.

16. A process for forming a deposited film according to claim 14, wherein the raw material gas further comprises a compound which contains nitrogen atoms.

17. A process for forming a deposited film according to claim 14, wherein the raw material gas further comprises a compound which contains oxygen atoms.

18. A process for forming a deposited film according to claim 13, wherein a raw material gas for forming the i-type semiconductor layer comprises a gasifiable compound which contains germanium atoms.

19. A process for forming a deposited film according to claim 18, wherein the raw material gas further comprises a compound which contains carbon atoms.

20. A process for forming a deposited film according to claim 18, wherein the raw material gas further comprises a compound which contains nitrogen atoms.

21. A process for forming a deposited film according to claim 18, wherein the raw material gas further comprises a compound which contains oxygen atoms.

22. A process for forming a deposited film according to claim 1, wherein said steps are performed in a single apparatus.

23. A process for forming a deposited film according to claim 1, wherein the first semiconductor layer has a first conductivity type.

24. A process for forming a deposited film according to claim 17, wherein said first semiconductor layer of first conductivity type is formed by plasma CVD.

25. A process for forming a deposited film according to claim 24, wherein said plasma CVD is high frequency plasma CVD.

26. A process for forming a deposited film according to claim 23, wherein the difference between the moving substrate temperatures for forming said first semiconductor layer having said first conductivity type and for forming said deposited film by glow discharge is 10°

C. or more.

27. A process for forming a deposited film according to claim 1, wherein the first semiconductor layer is an i-type semiconductor layer.

28. A process for forming a deposited film according to claim 27, wherein the i-type semiconductor layer is formed by high frequency plasma CVD.

10. A process for forming a deposited film according to claim 10, wherein the second semiconductor layer formed after the cooling step is an i-type semiconductor layer.

8. A process for forming a deposited film according to claim 10, wherein the first semiconductor layer has a first conductivity type.

9. A process for forming a deposited film according to claim 8, wherein the second semiconductor layer formed after the cooling step has a second conductivity type opposite to the first conductivity type of the first semiconductor layer.

11. A process for forming a deposited film according to claim 10, wherein the i-type semiconductor layer is formed by high frequency plasma CVD.

29. A process for continuously forming a deposited semiconductor film on an elongated moving substrate by plasma CVD in a vacuum chambers which comprises the steps of continuously moving said substrate in a lengthwise direction in said vacuum chamber, while heating said moving substrate immediately before the inlet of a glow discharge region of said vacuum chamber at a rate of 4°

C./second or higher, forming said semiconductor film on said moving substrate in said glow discharge region at a deposition rate of 0.1 nm/second to 20 nm/second by plasma CVD, and cooling said moving substrate at a rate of 4°

C./second or higher immediately after the outlet of said glow discharge region.

30. An apparatus for continuously forming a deposited film on an elongated moving substrate, comprising a vacuum chamber for forming a semiconductor layer having p-type or n-type conductivity on said moving substrate and a vacuum chamber for forming a semiconductor having i-type conductivity on said semiconductor layer having p-type or n-type conductivity, which comprises heating means disposed immediately before said vacuum chamber for forming said semiconductor having i-type conductivity and cooling means disposed immediately after said vacuum chamber for forming said semiconductor having i-type conductivity.

31. An apparatus for continuously forming a deposited film according to claim 30, wherein the heating means comprises a halogen lamp.

32. An apparatus for continuously forming a deposited film according to claim 30, wherein the heating means comprises a heating block.

33. An apparatus for continuously forming a deposited film according to claim 32, wherein the heating block can be brought into contact with the substrate.

34. An apparatus for continuously forming a deposited film according to claim 30, wherein the heating means comprises a heating roller.

35. An apparatus for continuously forming a deposited film according to claim 34, wherein the heating roller can be brought into contact with the substrate.

36. An apparatus for continuously forming a deposited film according to claim 30, wherein the heating means comprises an apparatus for generating a hot gas plasma.

37. An apparatus for continuously forming a deposited film according to claim 30, wherein the heating means comprises an apparatus for generating an inductive heating by electromagnetic waves.

38. An apparatus for continuously forming a deposited film according to claim 30, wherein the cooling means comprises a cooling pipe which is disposed adjacent to the substrate and through which a cooling medium passes.

39. An apparatus for continuously forming a deposited film according to claim 30, wherein the cooling means comprises a cooling block.

40. An apparatus for continuously forming a deposited film according to claim 39, wherein the cooling block can be brought into contact with the substrate.

41. An apparatus for continuously forming a deposited film according to claim 30, wherein the cooling means comprises a cooling roller.

42. An apparatus for continuously forming a deposited film according to claim 41, wherein the cooling roller can be brought into contact with the substrate.

43. An apparatus for continuously forming a deposited film according to claim 30, wherein the cooling means comprises an apparatus for spraying a gas having a low temperature.

44. An apparatus for continuously forming a deposited film according to claim 30, wherein the cooling means comprises a mechanism for cooling by air.

45. A process for forming a deposited film comprising forming a semiconductor having i-type Conductivity on a moving semiconductor substrate having p-type or n-type conductivity by glow discharge, wherein said moving semiconductor substrate having p-type or n-type conductivity is heated at a rate of 4°

C./second or higher before entering a region in which said glow discharge is performed.

46. A process for forming a deposited film which comprises the steps of:

forming a first semiconductor layer having p-type or n- type conductivity on a substrate, and

forming an i-type semiconductor layer on said first semiconductor layer by microwave CVD,

wherein the substrate on which the semiconductor layer having p-type or n-type conductivity is deposited is heated at a rate of 4°

C./second or more before the step of forming the i-type semiconductor layer.

47. A process for forming a deposited film according to claim 46, wherein an i-type semiconductor layer is formed on said first semiconductor layer by high frequency plasma CVD between the step of forming the semiconductor layer having p-type or n -type conductivity and the step of forming the i-type semiconductor layer by microwave plasma CVD.

48. A process for forming a deposited film Which comprises the steps of:

forming an i-type semiconductor layer on a substrate by microwave CVD, and

forming a second semiconductor layer on said i-type semiconductor layer having p-type or n-type conductivity,

wherein the substrate on which the i-type semiconductor layer is deposited is cooled at a rate of 4°

C./second or more after the step of forming the i-type semiconductor layer and before the step of forming the second semiconductor layer.

49. A process for forming a deposited film according to claim 48, wherein an i-type semiconductor layer is formed by high frequency plasma CVD between the step of forming the i-type semiconductor layer by microwave CVD and the step of forming the p-type or n-type semiconductor layer.