The authors developed a high throughput (70 Å/min) and scalable space-divided atomic layer deposition(ALD) system for thin film encapsulation (TFE) of flexible organic light-emitting diode(OLED) displays at low temperatures (<100 °C). In this paper, the authors report the excellent moisture barrier properties of Al2O3filmsdeposited on 2G glass substrates of an industrially relevant size (370 × 470 mm2) using the newly developed ALD system. This new ALD system reduced the ALD cycle time to less than 1 s. A growth rate of 0.9 Å/cycle was achieved using trimethylaluminum as an Al source and O3 as an O reactant. The morphological features and step coverage of the Al2O3films were investigated using field emission scanning electron microscopy. The chemical composition was analyzed using Auger electron spectroscopy. These deposited Al2O3films demonstrated a good optical transmittance higher than 95% in the visible region based on the ultraviolet visible spectrometer measurements. Water vapor transmission rate lower than the detection limit of the MOCON test (less than 3.0 × 10−3 g/m2 day) were obtained for the flexible substrates. Based on these results, Al2O3deposited using our new high-throughput and scalable spatialALD is considered a good candidate for preparation of TFE films of flexible OLEDs.
This study was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean Government (MEST) (NRF-2014R1A2A1A11053174).
I. INTRODUCTION II. EXPERIMENT A. Development of fast spatialALD B. Experimental details III. RESULTS AND DISCUSSION A. Film growth B. Chemical and optical properties C. Physical and moisture permeation barrier properties IV. SUMMARY AND CONCLUSIONS