Al2O3 multi-density layer structure as a moisture permeation barrier deposited by radio frequency remote plasma atomic layer deposition

作者：Jung Hyunsoo; Jeon Heeyoung; Choi Hagyoung; Ham Giyul; Shin Seokyoon; Jeon Hyeongtag

来源：Journal of Applied Physics, 2014, 115(7): 073502.

DOI：10.1063/1.4866001

Al2O3 films deposited by remote plasma atomic layer deposition have been used for thin film encapsulation of organic light emitting diode. In this study, a multi-density layer structure consisting of two Al2O3 layers with different densities are deposited with different deposition conditions of O-2 plasma reactant time. This structure improves moisture permeation barrier characteristics, as confirmed by a water vapor transmission rate (WVTR) test. The lowest WVTR of the multi-density layer structure was 4.7 x 10(-5) gm(-2) day(-1), which is one order of magnitude less than WVTR for the reference single-density Al2O3 layer. This improvement is attributed to the location mismatch of paths for atmospheric gases, such as O-2 and H2O, in the film due to different densities in the layers. This mechanism is analyzed by high resolution transmission electron microscopy, elastic recoil detection, and angle resolved X-ray photoelectron spectroscopy. These results confirmed that the multi-density layer structure exhibits very good characteristics as an encapsulation layer via location mismatch of paths for H2O and O-2 between the two layers.

• 出版日期2014-2-21