MANUFACTURING METHODS AND STRUCTURES FOR LARGE-AREA THIN-FILM SOLAR CELLS AND OTHER SEMICONDUCTOR DEVICES
Fabrication methods and structures relating to multi-level metallization for solar cells as well as fabrication methods and structures for forming back contact solar cells are provided.
1 . A back contact crystalline semiconductor solar cell structure, comprising:
a crystalline semiconductor substrate, said substrate comprising a light receiving frontside surface covered with a frontside passivation layer and a backside surface comprising patterned doped emitter and base regions and a backside passivation layer;
a first electrically conductive metallization layer having an interdigitated pattern of emitter electrodes and base electrodes on said backside surface of said crystalline substrate;
an electrically insulating layer attached to said backside surface of said crystalline substrate, said electrically insulating layer comprising an embedded patterned metallization sheet contacting said first electrically conductive layer at specified locations, said electrically insulating layer electrically isolating said first metallization layer from a second electrically conductive metallization layer; and
a second electrically conductive metallization layer providing high-conductivity cell interconnections to said embedded metallization sheet of said electrically insulating layer.
2 . The solar cell structure of claim 1 wherein said first electrically conductive metallization layer comprises aluminum.
3 . The solar cell structure of claim 1 wherein said embedded patterned metallization sheet comprises aluminum.
4 . A method for forming a back contact solar cell, comprising:
forming a first layer of electrically conductive metal having an interdigitated pattern of base electrodes and emitter electrodes on the backside surface of a crystalline semiconductor substrate, said substrate comprising a light receiving frontside surface and a backside surface for forming patterned emitter and base contacts silicon layer;
forming an electrically insulating layer on said first layer of electrically conductive metal, said electrically insulating layer comprising an embedded patterned metallization sheet contacting said first electrically conductive layer at specified locations, said electrically insulating layer providing electrical isolation between said first layer of electrically conductive metal and a second layer of electrically conductive metal;
forming holes in said electrically insulating layer, said holes providing access to said embedded metallization sheet contacting said first electrically conductive layer; and
forming a second electrically conductive metallization layer on said electrically insulating layer, said second electrically conductive metallization layer contacting said embedded metallization sheet contacting said first electrically conductive layer through said holes.
5 . A back contact crystalline semiconductor solar cell structure, comprising:
a crystalline semiconductor substrate, said substrate comprising a light receiving frontside surface covered with a frontside passivation layer for forming patterned base regions and a backside surface comprising patterned doped emitter regions and a backside passivation layer;
a frontside electrically conductive metallization layer having a pattern of base electrodes on said frontside surface of said crystalline substrate;
a backside electrically conductive metallization layer having a pattern of emitter electrodes on said backside surface of said crystalline substrate;
a backplane layer attached to said backside surface of said crystalline substrate, said backplane layer comprising an embedded metallization sheet contacting said backside electrically conductive layer.