Numerical simulation of electron transport through constriction in a metallic thin film

Electron transport through a constriction in a thin metallic film of finite thickness is simulated by numerically solving the Boltzmann transport equation (BTE) within the relaxation time approximation under linear response conditions. Such a structure closely represents vias connecting metal levels of different widths. Predicted reduction in effective electrical conductance due to electron surface scattering, which is significant when the dimensions are of the order of carrier mean free path, is compared with that for a constriction between semi-infinite spaces available in the literature. A simple expression for the size effect on conductance is fit to the simulated results applicable for constriction in a finite size thin film. The results could enable better estimate of effective resistance of next generation on-chip interconnections.