Solar cell and solar-cell module

A method for manufacturing a solar cell comprising a crystalline silicon substrate having a light-receiving surface, an emitter layer formed on the light-receiving surface side of the substrate, a passivation film formed on the emitter layer, an extraction electrode for extracting photogenerated charge from the silicon substrate, and a collector electrode in contact with at least a portion of the extraction electrode for collecting the charge drawn in the extraction electrode, comprising steps of:

• forming the emitter layer on the light-receiving surface of the crystalline silicon substrate of one conductivity type by diffusion of a first dopant of opposite conductivity type added thereto,
• forming the passivation film on the emitter layer,
• forming a first electrode which is part of the extraction electrode at least by sintering a first conductive paste containing conductive powder, glass frit and a second dopant for imparting conductivity to silicon which is printed on the passivation film, wherein during sintering of the first conductive paste on the passivation film, the passivation film reacts with the glass frit in the first conductive paste and is decomposed, and the conductive powder in the first conductive paste penetrates through the passivation film to make electrical contact with the substrate, and wherein below the interface between the emitter layer of the silicon substrate and the first electrode, a self-doping region is formed as a result of the second dopant in the first electrode being diffused during the sintering step, and
• forming a second electrode having a higher conductivity than the first electrode, which is part of the collector electrode at least in contact with at least a portion of the extraction electrode by sintering a second conductive paste containing a higher proportion of conductive powder than the proportion in the first conductive paste which is printed on the first electrode at least.