Ion implantation fabrication process for thin-film crystalline silicon solar cells

1. A method for the fabrication of an all back contact thin-film crystalline silicon solar cell from a thin-film silicon substrate, the method comprising:

forming a thin-film crystalline silicon substrate by the steps of:

forming a porous sacrificial layer on and conformal to the surface of a silicon template;

subsequently depositing an epitaxial silicon layer on said sacrificial layer;

selectively cutting said sacrificial layer in a predetermined size and pattern; and

releasing said epitaxial silicon layer from said silicon template;

implanting ions of an element in said thin-film silicon substrate to form emitter regions;

implanting ions of an element in said thin-film silicon substrate to form selective emitter regions;

implanting ions of an element in said thin-film silicon substrate to form a front surface field;

implanting ions of an element in said thin-film silicon substrate to form base regions; and

forming selective metallization contacts on said selective emitter regions and said base regions.

2. The method of claim 1 , wherein said thin-film crystalline silicon substrate is a three-dimensional thin-film crystalline silicon substrate.

3. The method of claim 2 , wherein said three-dimensional thin-film crystalline silicon substrate comprises a plurality of inverted pyramidal surface features comprising a top surface aligned along a (100) crystallographic orientation plane of said three-dimensional thin-film silicon substrate and a plurality of walls each aligned along a (111) crystallographic orientation plane of said three-dimensional thin-film crystalline silicon substrate.

4. The method of claim 2 , wherein said three-dimensional thin-film crystalline silicon substrate comprises a plurality of prism surface features.

5. The method of claim 1 , wherein said thin-film crystalline silicon substrate is substantially planar.

6. The method of claim 2 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form selective emitter regions further comprises implanting ions of an element in said thin-film silicon substrate to form selective emitter regions according to an angled ion implantation process.

7. The method of claim 1 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form emitter regions further comprises implanting ions of an element in said thin-film crystalline silicon substrate to form emitter regions with controlled dopant profiles.

8. The method of claim 1 , wherein said step of implanting ions of an element in said thin-film silicon substrate to form emitter regions further comprises implanting ions of an element in said thin-film silicon substrate to form homogeneous emitter regions.

9. The method of claim 1 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form a front surface field further comprises implanting ions of an element in said thin-film crystalline silicon substrate to form a homogeneous front surface field.

10. The method of claim 1 , further comprising the step of forming localized openings in a dielectric layer, comprising the steps of:

selectively implanting ions of an element which slows the growth of oxide during oxidation;

oxidizing to form a passivating oxide layer with selective openings; and

forming selective metallization contacts on said selective openings.

11. The method of claim 1 , further comprising the step of enhancing the field effect of said emitter regions and said back surface field.

12. A method for the fabrication of an all back contact thin-film crystalline silicon solar cell from a thin-film silicon substrate, the method comprising:

implanting ions of an element in said thin-film silicon substrate to form emitter regions;

implanting ions of an element in said thin-film silicon substrate to form selective emitter regions;

implanting ions of an element in said thin-film silicon substrate to form a front surface field;

implanting ions of an element in said thin-film silicon substrate to form base regions; and

forming selective metallization contacts on said selective emitter regions and said base regions, comprising the steps of:

forming localized openings in a dielectric layer, comprising the steps of:

selectively implanting ions of an element which slows the growth of oxide during oxidation;

oxidizing to form a passivating oxide layer with selective openings; and

forming selective metallization contacts on said selective openings.

13. The method of claim 12 , further comprising the step of:

forming a thin-film crystalline silicon substrate by the steps of:

forming a porous sacrificial layer on and conformal to the surface of a silicon template;

subsequently depositing an epitaxial silicon layer on said sacrificial layer;

selectively cutting said sacrificial layer in a predetermined size and pattern; and

releasing said epitaxial silicon layer from said silicon template.

14. The method of claim 12 , wherein said thin-film crystalline silicon substrate is a three-dimensional thin-film crystalline silicon substrate.

15. The method of claim 14 , wherein said three-dimensional thin-film crystalline silicon substrate comprises a plurality of inverted pyramidal surface features comprising a top surface aligned along a (100) crystallographic orientation plane of said three-dimensional thin-film silicon substrate and a plurality of walls each aligned along a (111) crystallographic orientation plane of said three-dimensional thin-film crystalline silicon substrate.

16. The method of claim 14 , wherein said three-dimensional thin-film crystalline silicon substrate comprises a plurality of prism surface features.

17. The method of claim 12 , wherein said thin-film crystalline silicon substrate is substantially planar.

18. The method of claim 14 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form selective emitter regions further comprises implanting ions of an element in said thin-film silicon substrate to form selective emitter regions according to an angled ion implantation process.

19. The method of claim 12 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form emitter regions further comprises implanting ions of an element in said thin-film crystalline silicon substrate to form emitter regions with controlled dopant profiles.

20. The method of claim 12 , wherein said step of implanting ions of an element in said thin-film silicon substrate to form emitter regions further comprises implanting ions of an element in said thin-film silicon substrate to form homogeneous emitter regions.

21. The method of claim 12 , wherein said step of implanting ions of an element in said thin-film crystalline silicon substrate to form a front surface field further comprises implanting ions of an element in said thin-film crystalline silicon substrate to form a homogeneous front surface field.

22. The method of claim 12 , further comprising the step of enhancing the field effect of said emitter regions and said back surface field.