Thick damage buffer for foil-based metallization of solar cells
Approaches for the foil-based metallization of solar cells and the resulting solar cells are described. A method involves patterning a first surface of a metal foil to provide a plurality of alternating grooves and ridges in the metal foil. Non-conductive material regions are formed in the grooves in the metal foil. The metal foil is located above a plurality of alternating N-type and P-type semiconductor regions disposed in or above a substrate to provide the non-conductive material regions in alignment with locations between the alternating N-type and P-type semiconductor regions and to provide the ridges in alignment with the alternating N-type and P-type semiconductor regions. The ridges of the metal foil are adhered to the alternating N-type and P-type semiconductor regions. The metal foil is patterned through the metal foil from a second surface of the metal foil at regions in alignment with the non-conductive material regions.
1. A method of fabricating a solar cell, the method comprising:
patterning a first surface of a metal foil to provide a plurality of alternating grooves and ridges in the metal foil;
forming non-conductive material regions in the grooves in the metal foil;
locating the metal foil above a plurality of alternating N-type and P-type semiconductor regions disposed in or above a substrate to provide the non-conductive material regions in alignment with locations between the alternating N-type and P-type semiconductor regions and to provide the ridges in alignment with the alternating N-type and P-type semiconductor regions;
adhering the ridges of the metal foil to the alternating N-type and P-type semiconductor regions; and
patterning the metal foil through the metal foil from a second surface of the metal foil at regions in alignment with the non-conductive material regions.
2. The method of claim 1 , wherein patterning the first surface of a metal foil comprises laser ablating a thickness of the metal foil approximately in the range of 90-95% of an entire thickness of the metal foil.
3. The method of claim 1 , wherein forming the non-conductive material regions in the grooves in the metal foil comprises applying and then curing a paste within the grooves in the metal foil.
4. The method of claim 1 , wherein patterning the first surface of the metal foil and forming the non-conductive material regions are performed as a roll-based process.
5. The method of claim 4 , further comprising:
subsequent to forming the non-conductive material regions and prior to locating the metal foil above the plurality of alternating N-type and P-type semiconductor regions, cutting the metal foil to have a perimeter substantially the same size as a perimeter of the substrate.
6. The method of claim 1 , wherein adhering the ridges of the metal foil to the alternating N-type and P-type semiconductor regions comprises using a technique selected from the group consisting of a laser welding process, a thermal compression process and an ultrasonic bonding process.
7. The method of claim 1 , wherein patterning the metal foil through the metal foil from the second surface of the metal foil exposes the non-conductive material regions.
8. The method of claim 1 , further comprising:
prior to locating the metal foil, forming a plurality of metal seed material regions to provide a metal seed material region on each of the alternating N-type and P-type semiconductor regions, wherein adhering the metal foil to the alternating N-type and P-type semiconductor regions comprises adhering the metal foil to the plurality of metal seed material regions.
9. The method of claim 8 , wherein forming the plurality of metal seed material regions comprises forming aluminum regions each having a thickness approximately in the range of 0.3 to 20 microns and comprising aluminum in an amount greater than approximately 97% and silicon in an amount approximately in the range of 0-2%, wherein adhering the metal foil comprises adhering an aluminum with the ridges having a thickness approximately in the range of 50-100 microns.