The contribution of grain boundary scattering versus surface scattering to the resistivity of thin polycrystalline films

Materials with nanometric dimensions exhibit higher electrical resistivity due to additional scattering centers for the conduction electrons, mainly from surfaces and grain boundaries. In this study we focus on the effect of grain boundaries by modeling the expected resistivity due to the observed log-normal distribution of boundaries, unlike the widely used model of Mayadas and Shatzkes that assumes a Gaussian distribution. The results of the model are then experimentally explored by correlating the resistivity of thin copper films with their grain size distribution. Applying a newly suggested analysis method solves the ambiguity in distinction between surface scattering and grain boundaries scattering. It is found that for the explored layers the increase in resistivity is dominated by the effect of grain boundaries.