Characterization of oxide barrier layers prepared by atomic layer deposition

Abstract

Atomic layer deposition has become an important thin-film growth technique for producing gas diffusion barriers because of its low process temperature and its ability to produce uniform films. In this work, atomic layer deposition was used to deposit various Al2O3 and ZnO thin films on polyethylene terephthalate substrates; subsequently, the physical properties and water vapor transmission rates of the films were characterized. Single and hybrid films (Al2O3, ZnO, Al2O3/ZnO, and ZnO/Al2O3) with thicknesses of 25, 50, and 100 nm at a deposition temperature of 60°C were investigated. The deposited films were characterized for surface roughness, optical transmittance, adhesion, water vapor transmission rate, and contact angle. The results showed that the double-layer structure provided a higher water vapor transmission rate and higher adhesion strength than those of the single-layer structure although both the surface roughness and optical transmittance of the single-layer structure were slightly better than those of the double-layer structure. The results revealed that the atomic layer deposition-grown hybrids could act as water vapor barriers.