Preparation of SiNx multilayer films by mid-frequency magnetron sputtering for crystalline silicon solar cells

Abstract The purpose of this study is to design hydrogenated silicon nitride/silicon nitride/silicon oxynitride (SiN x :H/SiN x /SiO x N y ) multilayer films for silicon crystalline solar cells by using mid-frequency (MF) magnetron sputtering technique. Both anti-reflection and surface passivation are taking into account. Single SiN x and SiN x /SiO x N y multilayer films were firstly deposited on textured silicon wafer for optical performance evaluation. SiN x /SiO x N y film acted as antireflective layer with minimal value of 4.03% reflectance after numerical optimization. The N composition in the SiN x film was increased and its reflectance was decreased as the increase of the flow of N 2 . A significant O contamination was observed in all of these coatings. Then SiN x :H film employed as passivation layer was involved into SiN x /SiO x N y films system. SiN x :H/SiN x /SiO x N y multilayer films still presented excellent optical quality with 5.43% reflectance. Solar cell with SiN x :H/SiN x /SiO x N y films exhibited 575 mV open circuit voltage, which was higher than the cell with silicon dioxide (SiO 2 ) film (569 mV) and with SiN x /SiO x N y film (561 mV). Finally, SiN x :H/SiN x /SiO x N y films were applied in conventional industrial solar cell preliminarily and 17.32% best cell efficiency was achieved.