High quality crystalline silicon surface passivation by combined intrinsic and n-type hydrogenated amorphous silicon

We investigate the influence of thermal annealing on the passivation quality of crystalline silicon (c-Si) surfaces by intrinsic and n-type hydrogenated amorphous silicon (a-Si:H) films. For temperatures up to 255 °C, we find an increase in surface passivation quality, corresponding to a decreased dangling bond density. Due to the combined chemical and field effect passivation of the intrinsic/n-type a-Si:H layer stack, we obtained minority carrier lifetimes with a value as high as 13.3 ms at an injection level of 10¹⁵ cm⁻³. For higher annealing temperatures, a decreased passivation quality is observed, which is attributed to hydrogen effusion.