Photovoltaic elements and process and apparatus for their formation

• US 5,589,007 A
• Filed: 09/05/1995
• Issued: 12/31/1996
• Est. Priority Date: 01/29/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sakai, Akira, Kanai, Masahiro, Tamura, Hideo, Fujioka, Yasushi, Hori, Tadashi, Yasuno, Atsushi, Okabe, Shotaro
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/523,169
• Time in Patent Office: 483 Days
• Field of Search: 136/249 TJ, 136/258 AM, 437/4, 437/101, 437/108-109, 437/113, 257/53, 257/55, 257/458, 118/718-719, 118/723 R, 118/723 MW, 118/723 E
• US Class Current: 136/249
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• 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 31/204 including AIVBIV alloys, e.g. SiGe, SiC
• 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 10/547 Monocrystalline silicon PV cells
• 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 photovoltaic element comprises a first non-monocrystalline silicon-containing semiconductor layer of a first-conductivity type, a first i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a second i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, and a second non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first-conductivity type, wherein the second semiconductor layer is formed by plasma doping.

Claims

1. A photovoltaic element comprising a first non-monocrystalline silicon-containing semiconductor layer of a first-conductivity type, a first i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a second i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, and a second non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first-conductivity type;

said second semiconductor layer of opposite conductivity type being formed by plasma doping.

2. A photovoltaic element formation process that forms a multi-layered silicon-containing non-monocrystalline semiconductor film on a substrate, comprising the sequential steps of:

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD; and

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping.

3. A photovoltaic element formation apparatus capable of continuously forming a multi-layered silicon-containing non-monocrystalline semiconductor film on a belt-like substrate, comprising:

an unwind chamber from which said belt-like substrate is unwound;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a first i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which a second i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a non-monocrystalline silicon-containing p- or n- type semiconductor layer is formed by plasma doping; and

a wind-up chamber in which said belt-like substrate is wound up;

all of said chambers being arranged in this order in the direction of transport of said belt-like substrate, each of said chambers being connected with its adjoining chamber via a gas gate, and said belt-like substrate being continuously transported through the respective film-forming chambers so that the multi-layered silicon-containing non-monocrystalline semiconductor film is continuously formed thereon.

4. The apparatus according to claim 3, wherein a film-forming chamber in which a third i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD is further provided via a gas gate, between the film-forming chamber in which the n- or p-type semiconductor layer is formed by high-frequency plasma CVD and the film-forming chamber in which the first i-type semiconductor layer is formed by microwave plasma CVD.

5. The apparatus according to claim 3, wherein a hydrogen plasma treatment chamber is further provided via a gas gate, between the film-forming chamber in which the second i-type semiconductor layer is formed by high-frequency plasma CVD and the film-forming chamber in which the p- or n-type semiconductor layer is formed by plasma doping.

6. The apparatus according to claim 3, wherein a glow discharge cleaning chamber is further provided via a gas gate, between the unwind chamber and the film-forming chamber in which the n- or p-type semiconductor layer is formed by high-frequency plasma CVD.

7. The apparatus according to claim 3, wherein the discharge frequency in the film-forming chamber in which the p- or n-type semiconductor layer is formed by plasma doping is from 5 kHz to 500 kHz.

8. A photovoltaic element comprising a first non-monocrystalline silicon-containing semiconductor layer of a first-conductivity type, a first i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a second i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, a second non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first-conductivity type, a third non-monocrystalline silicon-containing semiconductor layer of the first conductivity type, a third i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a fourth i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, a fourth non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first conductivity type, a fifth non-monocrystalline silicon-containing semiconductor layer of the first conductivity type, a fifth i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a sixth i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, and a sixth non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first conductivity type;

said second semiconductor layer, said fourth semiconductor layer and said sixth semiconductor layer, each of opposite conductivity type, being formed by plasma doping.

9. A photovoltaic element formation process that forms a multi-layered silicon-containing non-monocrystalline semiconductor film on a substrate, comprising the sequential steps of:

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping;

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping;

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD; and

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping.

10. A photovoltaic element formation apparatus capable of continuously forming a multi-layered silicon-containing non-monocrystalline semiconductor film on a belt-like substrate, comprising:

an unwind chamber from which said belt-like substrate is unwound;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping; and

a wind-up chamber in which said belt-like substrate is wound up;

all of said chambers being arranged in this order in the direction of transport of said belt-like substrate, each of said chambers being connected with its adjoining chamber via a gas gate, and said belt-like substrate being continuously transported through the respective film-forming chambers so that the multi-layered silicon-containing non-monocrystalline semiconductor film is continuously formed thereon.

11. The apparatus according to claim 10, wherein a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD is further provided via a gas gate, at one or more locations between a film-forming chamber in which an n- or p-type semiconductor layer is formed by high-frequency plasma CVD and a film-forming chamber in which an i-type semiconductor layer is formed by microwave plasma CVD.

12. The apparatus according to claim 10, wherein a hydrogen plasma treatment chamber is further provided via a gas gate, at one or more locations between a film-forming chamber in which an i-type semiconductor layer is formed by high-frequency plasma CVD and a film-forming chamber in which a p- or n-type semiconductor layer is formed by plasma doping.

13. The apparatus according to claim 10, wherein a glow discharge cleaning chamber is further provided via a gas gate, between the unwind chamber and the film-forming chamber in which an n- or p-type semiconductor layer is formed by high-frequency plasma CVD.

14. The apparatus according to claim 10, wherein the discharge frequency in the film-forming chambers in which the p- or n-type semiconductor layers are formed by plasma doping is from 5 kHz to 500 kHz.

15. A photovoltaic element comprising a first non-monocrystalline silicon-containing semiconductor layer of a first-conductivity type, a first i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a second i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, a second non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first-conductivity type, a third non-monocrystalline silicon-containing semiconductor layer of the first conductivity type, a third i-type non-monocrystalline silicon-containing semiconductor layer formed by microwave plasma CVD, a fourth i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, a fourth non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first conductivity type, a fifth non-monocrystalline silicon-containing semiconductor layer of the first conductivity type, a fifth i-type non-monocrystalline silicon-containing semiconductor layer formed by high-frequency plasma CVD, and a sixth non-monocrystalline silicon-containing semiconductor layer of a conductivity type opposite to the first conductivity type;

said second semiconductor layer, said fourth semiconductor layer and said sixth semiconductor layer, each of opposite conductivity type, being formed by plasma doping.

16. A photovoltaic element formation process that forms a multi-layered silicon-containing non-monocrystalline semiconductor film on a substrate, comprising the sequential steps of:

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping;

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by microwave plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping;

forming an n- or p-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD;

forming an i-type non-monocrystalline silicon-containing semiconductor layer by high-frequency plasma CVD; and

forming a p- or n-type non-monocrystalline silicon-containing semiconductor layer by plasma doping.

17. A photovoltaic element formation apparatus capable of continuously forming a multi-layered silicon-containing non-monocrystalline semiconductor film on a belt-like substrate, comprising:

an unwind chamber from which said belt-like substrate is unwound;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by microwave plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping;

a film-forming chamber in which an n- or p-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD;

a film-forming chamber in which a p- or n-type non-monocrystalline silicon-containing semiconductor layer is formed by plasma doping; and

a wind-up chamber in which said belt-like substrate is wound up;

all of said chambers being arranged in this order in the direction of transport of said belt-like substrate, each of said chambers being connected with its adjoining chamber via a gas gate, and said belt-like substrate being continuously transported through the respective film-forming chambers so that the multi-layered silicon-containing non-monocrystalline semiconductor film is continuously formed thereon.

18. The apparatus according to claim 17, wherein a film-forming chamber in which an i-type non-monocrystalline silicon-containing semiconductor layer is formed by high-frequency plasma CVD is further provided via a gas gate, at one or more locations between a film-forming chamber in which an n- or p-type semiconductor layer is formed by high-frequency plasma CVD and a film-forming chamber in which an i-type semiconductor layer is formed by microwave plasma CVD.

19. The apparatus according to claim 17, wherein a hydrogen plasma treatment chamber is further provided via a gas gate, at one or more locations between a film-forming chamber in which an i-type semiconductor layer is formed by high-frequency plasma CVD and a film-forming chamber in which a p- or n-type semiconductor layer is formed by plasma doping.

20. The apparatus according to claim 17, wherein a glow discharge cleaning chamber is further provided via a gas gate, between the unwind chamber and the film-forming chamber in which an n- or p-type semiconductor layer is formed by high-frequency plasma CVD.

21. The apparatus according to claim 17, wherein the discharge frequency in the film-forming chambers in which the p- or n-type semiconductor layers are formed by plasma doping is from 5 kHz to 500 kHz.