All-in-vacuum deposited transparent multilayer barries on polymer substrates

To meet the high water vapour and oxygen permeation barrier requirements of flexible electronic devices many groups suggest multilayer stacks. We have developed a concept for roll-to-roll all-in-vacuum production of multilayer barrier stacks. It is based on the combination of reactively sputtered layers with an interlayer grown by Magnetron-PECVD. Magnetron-PECVD is a novel technology that allows the deposition of both silicon-oxide like and polymer like layers using a dual magnetron system. The combination of reactive sputtering and Magnetron-PECVD has been installed in a pilot-scale roll-to-roll coating unit. Process parameters like deposition rates and long term stability are characterized as well as coating uniformity. In addition to that the most important properties of the different constituents of the multilayer stacks are summarized. Based on the given results the most suitable sputtered barrier layer materials are suggested. Also, SiOxCyHz layers grown by Magnetron-PECVD are characterized regarding their barrier, optical and mechanical properties. In the next sections the stability of single and multi-layers versus linear strain is discussed. The linear strain test allows an approximation of the minimum bending radius for the layer stack on different substrates. The multilayer concept also allows the deposition of multifunctional layer stacks. Different examples that use a combination of sputtered and PECVD based layers will be shown.