Percolation of a simulated metallic film on a porous substrate: The copper-polyimide interface

Abstract

A simulation of the copper-polyimide interface previously investigated at low coverage is extended into the regime of higher metal-atom coverages. The evolution of film growth spanning regimes of independent cluster formation, percolating cluster formation, and continuous pinhole-free film growth is examined within the context of the model. Characterization of the ''fuzzy'' interface formed by metallic deposition onto a porous substrate is discussed. The effect of attractive metallic interactions and consequent induced-particle correlations on the percolation threshold of the deposit is examined. Enhancement or suppression of this threshold is found to depend upon the defined range of connectivity. Finite-size scaling in connection with the algorithm simulating deposition onto a cold substrate has been examined. Critical indices of the thin-film correlation length obtained for this three-dimensional simulation model with significant concentration gradient have been found to exhibit two-dimensional universal behavior within the accuracy of the calculations. The dependence of the percolation transition on the lattice anisotropy and interaction anisotropy is described. © 1994 The American Physical Society.