Method of manufacturing crystalline silicon solar cells using co diffusion of Boron and Phosphorus
View Patent ↗A method of manufacturing a crystalline silicon solar cell, subsequently including: providing a crystalline silicon substrate having a first side and a second side opposite the first side; pre-diffusing Phosphorus into a first side of the substrate to render a Phosphorus diffused layer having an initial depth; blocking the first side of the substrate; exposing a second side of the substrate to a Boron diffusion source; heating the substrate for a certain period of time and to a certain temperature so as to diffuse Boron into the second side of the substrate and to simultaneously diffuse the Phosphorus further into the substrate.
1. Method of manufacturing a crystalline silicon solar cell, subsequently comprising:
providing a crystalline silicon substrate having a first side and a second side opposite said first side;
pre-diffusing Phosphorus into said first side of said substrate which renders a film comprising SiO 2 and P 2 O 5 and a Phosphorus diffused layer having an initial depth;
removing said SiO 2 :P 2 O 5 film from all sides of said substrate;
blocking said first side of said substrate;
exposing said second side of said substrate to a Boron diffusion source;
heating said substrate for a certain period of time and to a certain temperature so as to diffuse Boron into said second side of said substrate and to simultaneously diffuse said Phosphorus further into said substrate.
2. Method according to claim 1 , wherein said pre-diffusing Phosphorus into a first side of said substrate comprises:
heating said substrate in an atmosphere including O 2 and P 2 O 5 so as to produce the film comprising SiO 2 and P 2 O 5 and an intermediate Phosphorus diffused layer on all sides of said substrate;
etching out said a Phosphorus diffused layer except for said first side.
3. Method according to claim 1 , wherein said pre-diffusing Phosphorus into a first side of said substrate comprises:
forming a coating on said first side using a screen-printed method, a single side spin-on method, or a single side spray-on method, said coating comprising P 2 O 5 and SiO 2 ;
heating said substrate so as to produce the film comprising SiO 2 and P 2 O 5 , and an intermediate Phosphorus diffused layer on all sides of said substrate;
etching out said a Phosphorus diffused layer except for said first side.
4. Method according to claim 1 , wherein said pre-diffusing Phosphorus into a first side of said substrate comprises:
blocking said second side of said substrate;
heating said substrate in an atmosphere including O 2 and P 2 O 5 , so as to produce the film comprising SiO 2 and P 2 O 5 and an intermediate Phosphorus diffused layer on all sides of said substrate.
5. Method according to claim 1 , wherein said pre-diffusing Phosphorus into a first side of said substrate comprises:
blocking said second side of said substrate;
forming a coating on said first side using a screen-printed method, a single side spin-on method, or a single side spray-on method, said coating comprising P 2 O 5 and SiO 2 ;
heating said substrate so as to produce the film comprising SiO 2 and P 2 O 5 , and a Phosphorus diffused layer on all sides of said substrate.
6. Method according to claim 2 , wherein heating said substrate is at a temperature of 800˜900° C.
7. Method according to claim 4 , wherein said second side of said substrate is blocked by way of forming a diffusion blocking layer on said second side.
8. Method according to claim 4 , wherein said second side of said substrate is blocked by another substrate.
9. Method according to claim 1 , wherein said first side of said substrate is blocked by a first side of another substrate.
10. Method according to claim 9 , wherein said other substrate comprises a processed substrate which is at the time of said blocking, similarly processed as said substrate.
11. Method according to claim 1 , wherein said first side of said substrate is blocked by way of covering said first side of said substrate with a coating layer.
12. Method according to claim 1 , wherein said exposing of said second side of said substrate to a Boron diffusion source comprises exposing said substrate to an atmosphere including O 2 and B 2 O 3 .
13. Method according to claim 12 , wherein said certain period of time lies between 30-120 minutes.
14. Method according to claim 12 , wherein said certain temperature lies between 900-1000° C.
15. Method according to claim 12 , wherein said B 2 O 3 is produced by leading N 2 through a BBr 3 liquid.
16. A solar cell manufactured by a method according to claim 1 .
17. Method according to claim 5 , wherein said second side of said substrate is blocked by way of forming a diffusion blocking layer on said second side.
18. Method according to claim 5 , wherein said second side of said substrate is blocked by another substrate.
19. Method according to claim 13 , wherein said certain temperature lies between 900-1000° C.
20. Method according to claim 13 , wherein said B 2 O 3 is produced by leading N 2 through a BBr 3 liquid.