Influence of Pressure on SiN_x:H Film by LF-PECVD

Hydrogenated silicon nitride films as an effective antireflection and passivation coating of silicon solar cell were prepared on p-type polished silicon substrate (1.0 Ωcm) by direct LF-PECVD (low frequency plasma enhanced chemical vapor deposition) of Centrotherm. The preferable passivation effect was obtained and the refractive index was in the range of 2.017-2.082. The refractive index of the hydrogenated silicon nitride films became larger with the increase of the pressure. Fourier transform infrared spectroscopy was used to study the pressure influence on the film structural properties. The results highlighted highhydrogen bond and high Si-N bonds density in the film, which were greatly influenced by the pressure. The passivation effect of the films was influenced by the Si dangling bonds density. Finally the effective minority liftetime degradation with time was shown and discussed by considering the relationship between the structural properties and passivation.