| This article deals with the problem of the contact between dielectric layers and aluminium on the rear side of solar cells and its impact on the passivation effect. Several dielectric layers and stacks of PECVD silicon ni- tride and silicon oxide have been deposited on monocrystalline and multicrystalline wafers to study their passivation behaviours. Solar cells were also elaborated with a dielectric/aluminium structure on the back side and a set of wafers was used to highlight the influence of aluminium capping dielectric layers on passivation. Although it is reported that all structures give similar passivations when composed of one layer of silicon nitride at least, capping them with alu- minium degrades the passivation below the standard aluminium BSF except for the SiNr/SiN stacks which is only slightly degraded. Consequently, solar cells are not as good as full aluminium coverage cells and it is found that the minority carrier lifetime and the internal quantum efficiency results are in contradiction with the I (V) results. This fact entails the need of performing complete solar cells to study the rear passivation by dielectric layers. |
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