Influence of aluminum workfunction and capping dielectric thickness on the performance of local back surface field solar cell using numerical simulation

[Display omitted] •For AlOx/SiNx stack, aluminum influence is overridden by high fixed charge density.•For SiOx/SiNx, surface recombination velocity is reduced two orders due to aluminum.•Reducing capping layer thickness enhances aluminum influence on passivated surface.•1% increase in efficiency of LBSF solar cell by exploiting aluminum influence. High efficiency partial rear contact solar cells forms a Metal-Insulator-Semiconductor (MIS) stack in the rear side. Aluminum is used as a local back surface field (localized heavily doped pregion) and a hole contact. The workfunction difference between the aluminum contact and the c-Si(p) causes inversion in the silicon surface of the MIS structure. The surface inversion affects the quality of passivation and hence, the performance of the solar cell which requires further understanding. In this work, we have analysed the influence of aluminum on surface passivation in two passivation stacks namely (i)AlOx/SiNx and (ii) SiOx/SiNx using Sentaurus TCAD simulation. Our simulation result shows that in case of positive dielectric stack (SiOx/SiNx), aluminum workfunction enhances the passivation (effective surface recombination velocity