Effect of gas flow rates in optimising silicon nitride films for large-area multicrystalline silicon solar cells

摘要

Silicon nitride (SiN_x:H) film is a promising material for antireflection coatings and for surface passivation in the conventional crystalline silicon (c-Si) solar cell process. In this work, SiN_x:H antireflective coating films were successfully fabricated by using conventional batch-type plasma-enhanced chemical vapour deposition system. Film thickness and refractive index (RI) of the samples were evaluated as functions of growth parameters, such as growth pressure, total gas flow rate, radio frequency power and NH_3 to SiH_4 gas ratio. In this work, an attempt has been made to elucidate the variation of electrical parameters of the multicrystalline silicon solar cells with respect to the gas flow rates and RI. The gas flow rate ratio, R = NH_3/SiH_4, was varied in the range of 0.09 to 0.12 by maintaining the total flow rate of the process gases at 7600 sccm. The variation of RI from 2.03 to 2.18 and the electrical parameters of the solar cells with respect to the gas flow ratio were interpreted and incorporated. Also the variation of efficiency correlated with the flow rate of SiH_4 during the deposition of silicon nitride process.