Gas barrier properties of SiON films deposited by plasma enhanced chemical vapor deposition at low temperature as a function of the plasma process parameters

Abstract

SiON barrier films were deposited on polyethylene terephthalate (PET) substrates at low temperatures (~60°) by plasma enhanced chemical vapor deposition (PECVD) for applications as transparent barrier packaging and flexible displays. The input power, bias and nitrogen flow rate in the radio frequency plasma were changed to optimize the barrier properties of the SiON film. The SiON film had a low defect and high density as a result of the plasma process and nitrogen chemistry synthesis. A high intensity of ions with a low temperature plasma process was suitable for improving the gas barrier properties of SiON film coatings. In addition, the film properties depend not only on the high ion current density (ion flux) and input power, but are also related to a SiON film with high density and Si–N chemical structure. The ion current density and substrate temperature were characterized using an oscilloscope and a thermometer, respectively. In addition, the coating properties were characterized by Fourier transform infrared (FT-IR) spectroscopy and the water vapor transmission rate (WVTR).