Influence of Structural Defects on the Resistivity and Current Flow Field in Conductive Thin Layers

Abstract

The paper presents an analysis of the influence of microcracks in textronic conductive layers on their conductive properties. The tested structures were created in the physical vacuum deposition process. The paper presents the results of computer simulations of the current flow field in thin conductive stripes with defects distributed along a line perpendicular to the stripe axis and randomly placed on its entire surface. It was found, inter alia, that a larger number of shorter collinear defects may have many times lower resistance than a small number of longer defects of the same total length (e.g., with 40 collinear cracks with a total length of 90% of the strip width, the sheet resistance is only about 3% greater compared to a track without cracks). It was found that the percolation threshold of the tested models with square proportions and randomly selected defects is close to the value of 0.5. This is consistent with the theoretical calculations for analogous discrete models with infinite sizes. It was also found that the sheet resistance of the conductive strip with randomly distributed defects clearly depends on its length when the defect concentration exceeds 20%. The simulations were carried out on the basis of the integral equation method, with the solution presented in the form of double layer potentials.