Silicon solar-cell processing for minimizing the influence of impurities and defects

Commercial Si solar cells are fabricated on low-cost wafers that contain high concentrations of impurities and defects. To achieve high device efficiency, cell-fabrication processing must include steps that can remove as-grown impurities and defects as much as possible and passivate the remaining. However, to maintain the cost effectiveness, these processes must be included as a part of a typical cell-fabrication sequence without increasing the number of process steps. This paper discusses various solar-cell processing approaches for minimizing deleterious effects of impurities and defects to yield high efficiency.