Gas Diffusion Barrier of Vapor Phase Infiltrated Pen with Room Temperature ALD

Abstract

Metal oxides like aluminum oxide (Al2O3) and silicon oxide (SiO2) are well known as gas barrier materials to moisture. The gas barrier films are used in various applications like food packaging, pharmaceuticals, chemicals, and organic electronics. Especially in the field of organic electronics, the high gas barrier performance is essential to avoid organic semiconducting material degradation from moisture. Because of the most attractive point in these devices is their possibility that of flexible device fabrication, we must use a flexible polymer film substrate. The polymer film substrate is thermally fragile, and it includes voids in polymer chains. From this, we have to deposit the gas barrier film at low temperature and uniformly coat the voids. To overcome these problems, we developed the room-temperature atomic layer deposition (RT-ALD) technologies. In this study, we examine gas barrier coatings with a combination of vapor phase infiltration (VPI) for higher barrier performances. The VPI produces a polymer-inorganic hybrid layer by infiltrating inorganic materials into polymer substrates in the subsurface region. It is possible to fill in the voids in polymer substrates.For VPI, we used tris(dimethylamino)silane (TDMAS) as the infiltration gas and plasma excited humidified Ar as oxidation gas. The infiltration process was operated at room temperature of 25 °C. The PEN film was infiltrated by being kept in a vacuum chamber with a TDMAS pressure of 200 Pa for 6 hours. After infiltration, the PEN films were exposed to plasma excited humidified Ar to oxidize surface absorbant. In the RT ALD, we used trimethylaluminum (TMA) and dimethylzinc (DMZ) as the precursor and oxidation gas was the same as VPI. We fabricated the gas barrier films with a ZnO single layer and a laminated Al2O3/ ZnO.In figure 1, we show Si 2p narrow scan spectra of TDMAS infiltrated PEN by X-ray photoelectron spectroscopy. The Si 2p peak existed after 90 min Ar bombardment etching. It indicates the TDMAS molecules penetrated in the PEN film. We also confirmed that its surface became smooth and its morphology was changed by using AFM. The surface modification by VPI was evaluated with a water contact angle meter. In this paper, we will release the WVTR data and discuss its performance compared with the pristine PEN. Figure 1