Deposition of SiO_x barrier films by O₂/TMDSO RF-PECVD

This paper reports that the SiO_x barrier films are deposited on polyethylene terephthalate substrate by plasma-enhanced chemical vapour deposition (PECVD) for the application of transparent barrier packaging. The variations of O₂/ Tetramethyldisiloxane (TMDSO) ratio and input power in radio frequency (RF) plasma are carried out to optimize barrier properties of the SiO_x coated film. The properties of the coatings are characterized by Fourier transform infrared, water vapour transmission rate (WVTR), oxygen transmission rate (OTR), and atomic force microscopy analysers. It is found that the O₂/TMDSO ratio exceeding 2:1 and the input power over 200 W yield SiO_x films with low carbon contents which can be good to the barrier (WVTR and OTR) properties of the SiO_x coatings. Also, the film properties not only depend on oxygen concentration of the inlet gas mixtures and input power, but also relate to the surface morphology of the coating.