Thin film encapsulation for OLED display using silicon nitride and silicon oxide composite film

In this paper, SiNx and SiOx films for OLED encapsulation were deposited by plasma-enhanced chemical vapor deposition (PECVD). The properties, including surface roughness, scratch adhesion between the films and substrates, water vapor permeation rate were investigated. The results showed that the root-mean-square (Rms) surface roughness of encapsulation film could be improved from 2.7 nm to 1.2 nm by depositing SiNx onto SiOx film. The SiOx film exhibited stronger adhesion strength to PET substrates compared with SiNx. The moisture barrier capability was enhanced immensely when SiOx/SiNx composite film instead SiNx or SiOx film. Moreover, according to the tests results, OLED devices were designed and fabricated on plastic substrates, were encapsulated with the optimized SiOx/SiNx composite film. The OLED devices can keep emitting during bending, the films were not found to crack. The results indicate that SiOx/SiNx composite film is a potential choice for the OLED encapsulation. Then more tests are needed in order to get a more precise investigation.