Protective region for metallization of solar cells
View Patent ↗Methods of fabricating a solar cell including metallization techniques and resulting solar cells, are described. In an example, a first and second semiconductor regions can be formed in or above a substrate, where a separation region is disposed between the first and second semiconductor regions. A protective region can be formed over the separation region. A first metal layer can be formed over the substrate, where the protective region prevents and/or inhibits damage to the separation region during the formation of the first metal layer. Conductive contacts can be formed over the first and second semiconductor regions.
1. A method of fabricating a solar cell, the method comprising:
forming a first and second semiconductor regions in or above a substrate, wherein a separation region is disposed between the first and second semiconductor regions;
forming a polysilicon region over the separation region;
forming an insulating layer between the polysilicon region and substrate, wherein the insulating layer includes openings;
forming a first metal layer over the polysilicon region and the insulating layer and within the openings of the insulating layer, wherein the polysilicon region inhibits damage to the separation region during the formation of the first metal layer;
forming conductive contacts over the first and second semiconductor regions; and
removing the polysilicon region.
2. The method of claim 1 , wherein forming the first metal layer comprises performing a sputtering process to form the first metal layer over the polysilicon region and the insulating layer and within the openings of the insulating layer, wherein the polysilicon region inhibits damage to the separation region during the sputtering process.
3. The method of claim 1 , wherein the separation region is a trench region.
4. The method of claim 1 , wherein forming the first metal layer comprises forming a metal seed layer over the polysilicon region and the insulating layer and within the openings of the insulating layer.
5. The method of claim 1 , wherein forming the first metal layer comprises forming a patterned metal seed layer over the polysilicon region and the insulating layer and within the openings of the insulating layer.
6. The method of claim 1 , wherein forming the polysilicon region over the separation region comprises depositing the polysilicon region over the separation region.
7. The method of claim 1 , wherein forming the polysilicon region over the separation region comprises:
forming a blanket polysilicon layer over the substrate;
forming a mask over portions of the blanket polysilicon layer,
etching exposed portions of the blanket polysilicon layer to form a polysilicon region over the separation region; and
removing the mask.
8. The method of claim 1 , wherein forming conductive contacts over the first and second semiconductor regions comprises:
forming a mask over portions of the first metal layer;
plating a second metal layer to exposed portions of the first metal layer;
removing the mask; and
performing an etching process to form conductive contacts over the first and second semiconductor regions.
9. The method of claim 1 , wherein forming conductive contacts over the first and second semiconductor regions comprises:
placing a metal foil over the first metal layer;
bonding the metal foil to the first metal layer; and
patterning the metal foil and first metal layer to form conductive contacts over the first and second semiconductor regions.
10. A method of fabricating a solar cell, the method comprising:
forming a first and second semiconductor regions in or above a substrate, wherein a separation region is disposed between the first and second semiconductor regions;
forming a protective region over the separation region;
forming an insulating layer between the protective region and substrate, wherein the insulating layer includes openings;
forming a first metal layer over the protective region and the insulating layer and within the openings of the insulating layer, wherein the protective region inhibits damage to the separation region during the formation of the first metal layer;
forming a mask over portions of the first metal layer;
plating a second metal layer to exposed portions of the first metal layer;
removing the mask; and
performing an etching process to form conductive contacts over the first and second semiconductor regions.
11. The method of claim 10 , wherein forming a protective region over the separation region comprises forming a protective region thermally stable at temperatures of at less than or equal to 300 degrees Celsius.
12. The method of claim 10 , wherein forming the first metal layer comprises performing a sputtering process to form the first metal layer over the protective region and the insulating layer and within the openings of the insulating layer, wherein the protective region inhibits damage to the separation region during the sputtering process.
13. The method of claim 10 , further comprising:
heating the substrate to a temperature of less than or equal to 300 degrees Celsius, wherein the protective region inhibits damage to the separation region during the heating.
14. The method of claim 10 , wherein the separation region is a trench region.
15. The method of claim 10 , wherein forming the first metal layer over the protective region and the insulating layer and within the openings of the insulating layer comprises forming a metal seed layer over the protective region, insulating layer and within the openings of the insulating layer.
16. The method of claim 10 , wherein forming the protective region over the separation region comprises forming a polymer over the separation region.
17. The method of claim 16 , wherein forming the polymer over the separation regions comprises forming a polyimide, silicone, polymeric silsesquioxane, epoxy or acrylic over the separation region.