Solar cell contact formation using laser ablation
View Patent ↗The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline material layer; and forming conductive contacts in the plurality of contact holes.
1. A method of fabricating a solar cell, the method comprising:
forming a first dielectric layer over a silicon substrate;
forming a poly-crystalline layer over the first dielectric layer;
forming an absorbing layer directly on the poly-crystalline layer;
before forming any other layer on the absorbing layer, forming, by laser processing, a plurality of contact holes through the absorbing layer; and
forming conductive contacts in the plurality of contact holes.
2. The method of claim 1 , wherein the absorbing layer comprises an amorphous layer.
3. The method of claim 1 , wherein the absorbing layer comprises silicon nitride.
4. The method of claim 1 , wherein the solar cell comprises a back-contact solar cell.
5. The method of claim 1 , wherein the silicon substrate comprises a single-crystalline substrate.
6. The method of claim 1 , wherein the plurality of contact holes is formed using a laser with a wavelength less than 1064 nanometers.
7. The method of claim 1 , wherein the plurality of contact holes is formed using a pico-second laser.
8. The method of claim 1 , wherein the first dielectric layer comprises a tunnel oxide.
9. A method of fabricating a solar cell, the method comprising:
forming a poly-crystalline layer over a silicon substrate;
forming an absorbing layer directly on the poly-crystalline layer; and
before forming any other layer on the absorbing layer, forming, by laser processing, a plurality of contact holes through the absorbing layer.
10. The method of claim 9 , wherein the absorbing layer comprises silicon nitride.
11. The method of claim 9 , wherein the absorbing layer comprises an amorphous layer.
12. The method of claim 9 , further comprising:
forming a silicon dioxide layer over the silicon substrate, wherein the poly-crystalline layer is formed between the silicon dioxide layer and the absorbing layer.
13. The method of claim 9 , wherein the plurality of contact holes is formed using a laser with a wavelength less than 1064 nanometers.
14. A method of fabricating a solar cell, the method comprising:
forming a silicon dioxide layer over a silicon substrate;
forming a poly-crystalline layer directly on the silicon dioxide layer;
forming an absorbing layer directly on the poly-crystalline layer;
before forming any other layer on the absorbing layer, forming, by laser processing, a plurality of contact holes that expose underlying doped regions of the solar cell through the absorbing layer; and
forming conductive contacts in the plurality of contact holes.
15. The method of claim 14 , wherein the absorbing layer comprises silicon nitride.
16. The method of claim 14 , wherein the absorbing layer comprises an amorphous layer.
17. The method of claim 14 , wherein the plurality of contact holes is formed using a laser with a wavelength less than 1064 nanometers.