Characterization of oxide gas barrier films

Year: 1999

Authors: Henry B.M., Dinelli F., Zhao K.-Y., Erlat A.G., Grovenor C.R.M., Briggs G.A.D., Kumar R.S., Howson R.P.

Autors Affiliation: Univ of Oxford, United Kingdom

Abstract: The aim of this study was to investigate the microstructure and the gas barrier performance of AlOx layers of varying thickness (23 to 34nm), deposited by magnetron sputtering on polyethylene terephthalate substrates. The gas barrier properties of the films were found to be good, as expected for the thickness range selected. A variety of techniques were used to microstructurally characterise the oxide coatings. Atomic force microscopy showed that the barrier layers had grown densely with an average grain size of 40nm. Also, it was shown that the coating surfaces were smooth, a feature that is believed to facilitate good water vapour barrier properties. High resolution electron microscopy showed that the barrier layers are amorphous and feature a small number of micro-pores up to 1 nm diameter size. A combination of the compactness, low surface roughness of the barrier coating together with few macro-scale defects are thought to be responsible for the good barrier properties shown by these films.

Conference title:

KeyWords: Microstructure; Alumina; Gas barrier layers; Oxygen; Scanning electron microscopy; Thickness measurement; High resolution electron microscopy