Enhanced Stable Regeneration of High Efficiency Cz PERC Cells

In this work we investigate the regeneration (permanent deactivation of light induced degradation, LID) of industrial high efficiency PERC cells. This procedure transforms the boron oxygen related defects responsible for LID into a less active state. Recently it was found that the hydrogen content in the passivation layer of boron doped Cz silicon lifetime samples plays a crucial role during regeneration. This effect is tested here on PERC cells fabricated with silicon nitride capping layers of different refractive indices and thus different compositions. We are able to confirm the results on cell level: PERC cells with high stable efficiencies of approximately 20% are achieved with an industrially applicable short regeneration step. The possibility of regeneration can be a very important factor when choosing the bulk resistivity with respect to the highest efficiency potential for PERC cells.