Flexible OLED Barrier Layer Silicon Oxide Nitride Stack

The patent applies composite materials by stacking multiple barrier layers with different compositions (silicon oxide and silicon nitride layers) to achieve both low water vapor transmission rate and sufficient adhesive strength. The alternating structure of hydrophilic silicon oxide layers and hydrophobic silicon nitride layers creates a composite barrier system that balances moisture protection with mechanical adhesion to the plastic substrate.

The barrier layer is segmented into multiple thin alternating layers of silicon oxide and silicon nitride rather than using a single thick layer. This segmentation allows each layer to contribute different properties: silicon oxide provides strong adhesion and moisture barrier, while silicon nitride provides stress management and additional barrier function, preventing peeling while maintaining low WVTR.

The patent uses composite materials (alternating silicon oxide and silicon nitride layers) to achieve effective impurity protection. While this creates a multi-layer structure, the systematic alternation of two well-known barrier materials provides both protection and manageability in manufacturing, as each layer can be deposited using standard PECVD processes.

The patent controls specific parameters of the barrier layers including thickness (50-200 nm per layer), silicon nitride composition (SiNx with x=1.1-1.3), and stress characteristics to optimize both protection performance and manufacturability. By precisely controlling these parameters, the complex multi-layer structure becomes manageable and reproducible in production.