Effects of O2 plasma treatment on moisture barrier properties of SiO2 grown by plasma-enhanced atomic layer deposition

Abstract We investigated the moisture barrier properties of SiO2 layers deposited via plasma-enhanced atomic layer deposition (PE-ALD) for encapsulation of an organic light-emitting diode (OLED). First, the growth characteristics and film properties of PE-ALD SiO2 using diisopropylamino silane (DIPAS) and O2 plasma were investigated. The film properties were significantly improved by applying proper O2 plasma treatment. The O2 plasma treatment increased the adsorption of the metal precursor by creating sufficient hydroxyl groups on the substrate. We not only increased the adhesion between the thin film and the polymeric substrate through O2 plasma treatment before the deposition process but also formed a high-density thin film, resulting in excellent moisture barrier properties. Consequently, the water vapor transmission rate (WVTR) was significantly reduced to 7.73 × 10−3 g/m2∙day, which was 10 times lower than that of a control sample. These newly developed methods can be applied to other metal oxides, such as Al2O3 and ZrO2, for OLED encapsulation with a low WVTR.