The influence of crystal orientation on surface passivation in multi-crystalline silicon

We present an approach to study the variation of the surface recombination velocity in multi-crystalline silicon wafers through photoluminescence imaging for thin, passivated and mirror polished wafers. The influence of crystal orientation on surface passivation is investigated for various passivating films, including silicon nitride and aluminum oxide. Our results show that the influence of surface orientation is negligible in well passivated multi-crystalline silicon wafers due to the detrimental effects of crystal defects. Our study on hydrogenated samples suggests that aluminum oxide passivation exhibits a similar surface dependence as native oxide passivation. A slight and different surface dependence is observed in one of the silicon nitride films used in the study.