Structures and methods of formation of contiguous and non-contiguous base regions for high efficiency back-contact solar cells

摘要

Fabrication methods and structures relating to multi-level metallization of solar cells are described. In one embodiment, a back contact solar cell comprises a substrate having a substrate having a light receiving frontside surface and a backside surface for forming patterned emitter and non-nested base regions. Interdigitated doped emitter and base regions are formed on a backside surface of a crystalline semiconductor substrate. A patterned electrically insulating layer stack comprising a combination of at least a doped layer and an undoped capping layer is formed on the patterned doped emitter and base regions. A contact metallization pattern is formed comprising emitter metallization electrodes contacting the emitter regions and non-nested base metallization electrodes contacting the base regions wherein the non-nested base metallization electrodes are allowed to go beyond the base regions to overlap at least a portion of said patterned insulator without causing electrical shunts in the solar cell.