Influence of defects in SiOx thin films on their barrier properties

The residual permeability of SiOx thin films or other thin diffusion barriers is often determined by film defects like pinholes or cracks. In this study, the influence of defects in barrier films on the gas permeability of packaging material has been investigated by numerical calculations. The influence of different geometry parameters has been studied systematically. The model accounts for a general defect shape with an arbitrary length to width ratio and has been extended to laminates, which consist of more than one polymeric layer. The results are presented in dimensionless form and can be applied to any barrier/polymer configuration where the permeability of the barrier material itself and its thickness can be neglected. It has been shown that for a given barrier film quality, the gas permeation is basically determined by the adjacent polymeric layer. The most favorable laminate configuration is when the barrier is sandwiched between two polymer films. (C) 2004 Elsevier B.V. All rights reserved.