Field effect passivation of plasma oxidized SiOx layer on boron emitter surface by PECVD

Abstract

An ultra thin surface passivation layer is essential to reduce the surface recombination and enhance the open circuit voltage for high efficiency crystalline silicon (c-Si) solar cells. In that, we developed charge injection controllable thin films of SiOX and SiNX layers by PECVD for surface passivation of boron emitter c-Si surface. The refractive index of the SiOX/SiNX stack was optimized by varying the SiH4, NH3 and N2O gas ratios. Lower Dit of 5 × 10¹⁰ cm⁻² eV⁻¹ and high Qeff of −1.71 × 10¹¹ cm⁻² was obtained for 10 nm thick SiOX layer. The fabricated n-Si bifacial cell with insertion of 10 nm thick SiOX layer archived efficiency (η) of 19.48 % with fill factor (FF) of 77.5 %, whereas the cell without SiOX layer showed an η of 18.20 % with FF of 75.77.