On the Influence of the SiNxComposition on the Firing Stability of Poly-Si/SiNxStacks

Industrial TOPCon cells commonly feature a TOPCon/SiN(x)stack for the passivation at the rear. In this layer stack system, the SiN(x)needs to function as a hydrogen source during the firing step to ensure a good passivation after firing. Herein, the composition of this SiN(x)layer is varied, and it is shown that a refractive index ofn > 2 is desirable to achieve proper hydrogenation of the TOPCon layer yielding aJ(0s)as low as 6.6 fA cm(-2)after firing on textured surface. The increased silicon content in the layer does not lead to negative effects when metallizing the samples and instead leads to less metal spiking resulting in aniV(OC)of 730 mV including the contacts with a low specific contact resistivity of approximate to 1 m omega cm(2).