Effect of carrier-induced hydrogenation on the passivation of the poly-Si/SiOx/c-Si interface

In the progress made in understanding carrier-induced degradation and regeneration in p-type mono and multi silicon solar cells, it was implied that hydrogen passivates certain defects during illuminated anneals at temperatures between 150-350°C. However, there are only few reports on the effect of carrier-induced regeneration (CIR) in n-type material. In this work, we apply a CIR treatment on samples structured as poly-silicon/tunnel oxide/n-type CZ. We present evidence suggesting that hydrogen passivation plays an important role in the regeneration process, and that improvement does not occur in the Si bulk but mainly at the Si/SiOx interface. For n-type poly, the Si/SiOx interface improves at temperatures of 250°C and above regardless of illumination and H-containing dielectric layer, and the rate of improvement is merely accelerated by illumination. For p-poly, the Si/SiOx interface is only stable in our experiments if the H-containing dielectric layer is present during CIR.