Comprehensive Investigation on the Stability of Silicon Nitride/Oxynitride as Thin-Film Encapsulation Layers Prepared by Plasma-Enhanced Chemical Vapor Deposition

This study discovered that silicon nitride/oxynitride barrier films as thin-film encapsulation in organic light-emitting diodes (OLED) exhibit stress-changing behavior when subjected to moisture corrosion. Subsequent in-depth investigation revealed that the corroding films exhibit a specific stress-changing trajectory, which can be employed to assess the reliability of a given film. The mechanism of stress variation was investigated, and the findings indicated that the transformation from Si–H, Si–N, and N–Si–O bonds into Si-OH bonds resulted in a compression stress change, while the reverse hydrolysis of Si-OH bonds led to a tension stress change. Furthermore, investigations have shown that the state of moisture barrier films (stable or unstable) was closely related with the content of N–Si–O and Si–N(−H 2 ) bonds. Finally, by modeling the phenomenon using the Taguchi experiment design, the reliability of the OLED panel encapsulated with stable films reached over 1000 h of storage in a harsh environment.