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.

Field Modeling of the Influence of Defects Caused by Bending of Conductive Textronic Layers on Their Electrical Conductivity

“…To solve it, the method of integral equations was used. Its detailed description and algorithm are presented in [ 34 , 35 ].…”

The Influence of the Skin Phenomenon on the Impedance of Thin Conductive Layers

“…The vector potential of the field originating from the uniformly distributed current flowing on the surface S0 is obtained by integrating (8) with respect to x0:…”

“…Electroconductive thin films can be produced via various methods, such as physical vacuum deposition (PVD) [8,9], chemical vapor deposition (CVD) [10], electrochemical deposition [11], spin-coating [12], sol-gel technology [13][14][15], magnetron sputtering [16], ink-jet printing [17,18], screen printing [19] or electrospinning [20]. The development of new applications based on flexible and wearable devices with large surface areas requires thin-film electronics that can be fabricated using solvent methods.…”

“…The peculiarity of conductive textronic layers compared to others found in electronic devices (e.g., printed circuit paths) is that their surfaces are not flat because they take a shape similar to the texture of a textile material, and they also contain microdefects. It turns out that these features have a significant impact on the conductive properties of such layers [8]. For this reason, the assessment of conductive parameters of textronic layers, such as resistance, inductance or capacitance, requires the use of quite complex field calculations.…”

“…Due to the complex issues of field distribution inside the electroconductive path, one of the simplifications adopted in this article is the homogeneous structure of the produced layer. In further work, the authors plan to expand the model and analyze the impact of occurring defects on its electrical parameters in the case of high-frequency current, similar to the work on a constant signal [8].…”