Properties of SiO_xN_y thin film deposited by low temperature plasma enhanced chemical vapor deposition using TEOS-NH₃-O₂-N₂ gas mixtures

In this study, a SiO_xN_y thin film was deposited on plastic substrates using tetraethylorthosilicate (TEOS)/O₂/ N₂/NH₃ gas mixtures at a low temperature using the plasma enhanced chemical vapor deposition (PECVD) driven by an inductively coupled plasma (ICP) with a capacitively coupled plasma (CCP) for biasing. Also, the effects of TEOS, N₂, and NH₃ gas flow rates on the properties of the deposited film were investigated. A transparent and impurity free SiO_xN_y film having 60 nm/min of deposition rate could be obtained at the gas mixture of 15 sccm TEOS in N₂, 10 sccm O₂, 75 sccm of N₂, and 20 sccm of NH₃ for 300 W of 13.56 MHz rf power and - 150 V of dc bias voltage. When a multilayer film composed of total nine layers (parylene (800 nm)/SiO_xN_y (60 nm)/parylene (280 nm)/ SiO_xN_y (60 nm)/...) was deposited on 200 μm-thick polyethersulfone (PES) using the optimized SiO_xN_y, the water vapor transmission rate (WVTR) of 0.0235 g/(m² day) could be obtained.