Optimisation of SiNx:H layer for multicrystalline silicon solar cells

Amorphous hydrogenated silicon nitride (a-SiNx:H) films were prepared by a plasma–enhanced chemical vapour deposition in a conventional direct plasma reactor operating at 13.56 MHz using a mixture of the silane (SiH₄) and ammonia (NH₃). The reflectance of SiNx films deposited onto Cz-Si polished wafers substrates was measured in the range of 300–1200 nm. The wavelength dependence of the refractive index n and the extinction coefficient k was determined by fitting a Cauchy model to the experimental reflectance. The influence of the flow NH₃/SiH₄ ratio on the optical constant n and k of SiNx films is presented. An optimisation of the antireflection coating on the flat and texturised substrate for encapsulated and non-encapsulated solar cells was performed using the SUNRAYS program.