This paper reports that the SiOx 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 SiOx 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 SiOx films with low carbon
contents which can be good to the barrier (WVTR and OTR) properties of the SiOx 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.