Method of fabricating a solar cell with a tunnel dielectric layer
Method of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.
1. A method of fabricating a solar cell, the method comprising:
consuming a portion of a substrate of the solar cell to provide a surface oxide layer of the substrate by exposing the substrate to a wet chemical solution; and
heating the surface oxide layer from a temperature below 500 degrees Celsius, to a temperature above 500 degrees Celsius, and then cooling back to a temperature below 500 degrees Celsius.
2. The method of claim 1 , wherein the wet chemical solution comprises an oxidizer selected from the group consisting of ozone (O 3 ) and hydrogen peroxide (H 2 O 2 ).
3. The method of claim 2 , wherein the wet chemical solution and the substrate are exposed to visible light radiation during the exposing.
4. The method of claim 1 , wherein heating the surface oxide layer to the temperature above 500 degrees Celsius comprises heating to a temperature of approximately 565 degrees Celsius.
5. The method of claim 1 , further comprising:
forming a material layer above the surface oxide layer.
6. The method of claim 5 , wherein forming the material layer comprises forming a polysilicon layer during the heating.
7. The method of claim 6 , wherein heating the surface oxide layer comprises forming a tunnel oxide layer, and wherein forming the polysilicon layer comprises forming an N+ type or P+ type active region on the tunnel oxide layer.
8. The method of claim 6 , further comprising:
forming a metal contact above the polysilicon layer.
9. The method of claim 1 , wherein the substrate comprises silicon and the oxide layer comprises silicon oxide.
10. The method of claim 1 , wherein the substrate is a bulk silicon substrate.
11. A method of fabricating a solar cell, the method comprising:
consuming a portion of a substrate of the solar cell to provide a surface oxide layer of the substrate by thermal oxidation; and
heating the surface oxide layer from a temperature below 500 degrees Celsius, to a temperature above 500 degrees Celsius, and then cooling back to a temperature below 500 degrees Celsius.
12. The method of claim 11 , wherein the surface oxide layer is formed by a low-pressure thermal oxidation process.
13. The method of claim 12 , wherein the low-pressure thermal oxidation process is performed in an atmosphere comprising oxygen (O 2 ).
14. The method of claim 11 , further comprising:
forming a material layer above the surface oxide layer.
15. The method of claim 14 , wherein forming the material layer comprises forming a polysilicon layer during the heating.
16. The method of claim 15 , wherein heating the surface oxide layer comprises forming a tunnel oxide layer, and wherein forming the polysilicon layer comprises forming an N+ type or P+ type active region on the tunnel oxide layer.
17. The method of claim 15 , further comprising:
forming a metal contact above the polysilicon layer.
18. The method of claim 11 , wherein the substrate comprises silicon and the oxide layer comprises silicon oxide.
19. The method of claim 11 , wherein the substrate is a bulk silicon substrate.
20. The method of claim 11 , wherein heating the surface oxide layer to the temperature above 500 degrees Celsius comprises heating to a temperature of approximately 565 degrees Celsius.