Improved silicon surface passivation achieved by negatively charged silicon nitride films

A corona discharge is used to create and store negative charge in the silicon nitride films of silicon dioxide/silicon nitride stacks. Effective lifetime measurements on both textured and planar, as well as both boron diffused and undiffused silicon samples passivated with silicon oxide/silicon nitride stacks, show that the creation of negative charge in the nitride layer results in an improvement in the surface passivation for all samples, with very low (<2 cm/s) effective surface recombination velocities demonstrated for planar, undiffused samples. The manipulation of charge can be exploited to improve the conversion efficiency of silicon solar cells.