Optimisation of SiNx:H anti-reflection coatings for silicon solar cells

The deposition of SiN_x:H as anti-reflection coating has become a standard step in industrial production of silicon solar cells. In the present work the improvement of the anti-reflection properties and thus the improvement of the short circuit current density by deposition of a SiNx:H double layer coating are investigated. It is shown that an optimised double layer coating with indices n₁ ap 1.8 and n₂ ap 2.1 only leads to an 1.3% improvement of short circuit current in comparison to an optimised single layer coating with n ap 1.9. But the deposition of a SiN_x:H layer with higher refractive index on the silicon surface is supposed to lead to a good surface and bulk passivation. The passivating properties of the optically optimised double layer coating will be investigated in following experiments.