Laser techniques for foil-based 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 semiconductor region can be formed in or above a substrate. A first metal layer can be formed over the semiconductor region. A laser can be applied over a first region of the metal layer to form a first metal weld between the metal layer and the semiconductor region, where applying a laser over the first region comprises applying the laser at a first scanning speed. Subsequent to applying the laser over the first region, the laser can be applied over a second region of the metal layer where applying the laser over the second region includes applying a laser at a second scanning speed. Subsequent to applying the laser over the second region, the laser can be applied over a third region of the metal layer to form a second metal weld, where applying the laser over the third region comprises applying the laser at a third scanning speed.
1. A solar cell, comprising:
a semiconductor region disposed in or above a substrate;
a metal layer over the semiconductor region;
a first non-circular shaped metal weld;
a second non-circular shaped metal weld; and
a first damaged region on the metal layer, wherein the first damaged region is located between the first and second non-circular shaped metal welds.
2. The solar cell of claim 1 , wherein the semiconductor region comprises an N-type polycrystalline region or a P-type polycrystalline region.
3. The solar cell of claim 1 , wherein the metal layer comprises a metal foil.
4. The solar cell of claim 1 , wherein the metal layer comprises aluminum.
5. The solar cell of claim 1 , further comprising a metal seed region disposed between the metal layer and the semiconductor region.
6. The solar cell of claim 5 , wherein the first and second non-circular shaped metal welds electrically connect the metal layer to the metal seed region.
7. The solar cell of claim 1 , wherein the first and second non-circular shaped metal welds comprise a first and second oblong shaped metal welds.
8. The solar cell of claim 1 , further comprising:
a third non-circular shaped metal weld; and
a second damaged region on the metal layer, wherein the second damaged region is located between the second and third non-circular shaped metal welds.