Room Temperature Deposition of SiNx and Plasma Polymer Layers for Flexible Multilayer Barrier Films by Plasma Enhanced Chemical Vapor Deposition Processes

Abstract

In this work, silicon nitride (SiNx) films were deposited on plastic substrates at room temperature close to 30[Formula: see text]C on polyethylenenaphthalate (PEN) films in an inductively coupled plasma (ICP) reactor with trisilylamine (TSA, N(SiH[Formula: see text]) precursor and ammonia for flexible moisture barrier films. Moisture barrier property is improved as SiNx layer gets thicker, but cracks are found at thicker films above 300[Formula: see text]nm or more. And the barrier performance of the thicker layers is degraded significantly. In order to improve both flexibility and barrier property, plasma polymer (PP) layers were deposited at room temperature and introduced between the SiNx layers. The water vapor transmission rate (WVTR) of a single SiNx film, [Formula: see text][Formula: see text]g/(m[Formula: see text]), is reduced to [Formula: see text][Formula: see text]g/(m[Formula: see text]) with SiNx/PP/SiNx/PP/SiNx alternating five-layer structure. After 1000 times bending in 1.5[Formula: see text]cm of bending radius, the WVTR increases by 41% with five-layer structure, while that of single-layer structure increases by 69%. This work demonstrated that the SiNx and PP layers can be deposited at room temperature for flexible moisture barrier films.