Seed layers and process of manufacturing seed layers

Abstract

This invention relates seed layers and a process of manufacturing seed layers for casting silicon suitable for use in solar cells or solar modules. The process includes the step of positioning tiles with aligned edges to form seams on a suitable surface, and the step of joining the tiles at the seams to form a seed layer. The step of joining includes heating the tiles to melt at least a portion of the tiles, contacting the tiles at both ends of at least one seam with electrodes, using plasma deposition of amorphous silicon, applying photons to melt a portion of the tiles, and/or layer deposition. Seed layers of this invention include a rectilinear shape of at least about 500 millimeters in width and length.

1 . A process for manufacturing silicon seed layers suitable for use in the manufacture of solar cells or solar modules, the process comprising:
 positioning tiles with aligned edges to form seams on a suitable surface; and   joining the tiles at the seams to form a seed layer.   
     
     
         2 . The process of  claim 1 , wherein the joining comprises:
 heating the tiles to melt at least a portion of the tiles and close the seams; and   cooling the seed layer.   
     
     
         3 . The process of  claim 2 , further comprising:
 repositioning the seed layer with respect to a top side and a bottom side following cooling the seed layer;   reheating the seed layer to melt at least a previously unmelted portion of the seed layer and close the seams; and   recooling the seed layer.   
     
     
         4 . The process of  claim 2 , wherein the cooling comprises about 100 degrees Celsius an hour. 
     
     
         5 . The process of  claim 1 , wherein the joining comprises:
 contacting the tiles at both ends of at least one seam with electrodes;   flowing electrical current through the tiles between the electrodes to melt at least a portion of the tiles and close the seams;   optionally repeating the contacting and the flowing for each seam in the layer; and   cooling the seed layer.   
     
     
         6 . The process of  claim 5 , wherein the electrodes remain stationary with respect to the tiles during the flowing electrical current. 
     
     
         7 . The process of  claim 5 , wherein at least one electrode moves with respect to the tiles during the flowing of the electrical current. 
     
     
         8 . The process of  claim 5 , wherein the electrodes comprise highly doped silicon. 
     
     
         9 . The process of  claim 1 , wherein the joining comprises plasma deposition of amorphous silicon to close the seams. 
     
     
         10 . The process of  claim 9 , wherein the deposition of amorphous silicon comprises conformal plasma deposition.