Grain boundary contribution to the electrical conductivity of polycrystalline Cu films

Cu films of 1000 AA were grown at various substrate temperatures with increasing grain sizes at 10-5 Torr. The grain boundary resistivity ( rho gb=3.58*10-12 Omega cm2) and reflection coefficient (R=0.2635) at room temperature (22 degrees C) remained almost the same for different grain sizes, suggesting that the potential barrier between adjoining grains remains the same. Impurities and other defects have negligible effect on these values of rho gb and R. Results support the Mayadas-Schatzkes (M-S) grain boundary model (1970) of electrical conductivity for polycrystalline films.