Transparent oxygen impermeable AlO x thin films on polycarbonate deposited by reactive ion beam sputtering Jin-Wook Seong a, * , Sang-Mun Kim b , Daiwon Choi c , K.H. Yoon d a Advanced OLED Group, TD 1 Team, Corporate R&D Center, Samsung SDI Co. Ltd., 428-5 Gongse-Ri, Kiheung-Eup, Yongin-City Gyeonggi-Do, Korea 442-902 b Systems Technology Division, Korea Institute of Science and Technology (KIST), 39-1 Hawolgok-Dong, Seongbuk-gu, Seoul, Republic of Korea c Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA d Department of Ceramic Engineering, Yonsei University, Sudaemun-Gu, Shinchon-Dong 134, Seoul 120-749, Korea Received 17 October 2004; received in revised form 14 November 2004; accepted 15 November 2004 Available online 30 December 2004 Abstract The AlO x thin films were deposited on the polycarbonate by reactive ion beam sputtering (RIBS) at different oxygen partial pressures where the AlO x thin film with O/Al ratio of 1.5 was formed when oxygen partial pressure increased from 4 Â 10 À5 to 2 Â 10 À4 Torr. As a result, oxygen transmission rate (OTR) of the barrier significantly decreased from 24 cm 3 /m 2 day to around 2 cm 3 /m 2 day with increase in oxygen partial pressure. Optical transmittances of the films were in the 86–88% range at 550 nm versus 89% for the pure polycarbonate film. # 2004 Elsevier B.V. All rights reserved. Keywords: AlO x thin films; Oxygen partial pressure; Reactive ion beam sputtering (RIBS); Stoichiometric ratio; Oxygen transmission rate (OTR) 1. Introduction Deposition of aluminum oxide thin film on plastic substrate has been extensively studied for the last few years [1,2]. Transparent metal oxide thin films are used for flat panel displays, food and medical device packaging applications. Compared to metal barrier thin films, oxide barrier thin films have a number of advantages including transparency, recyclability, retort- ability, and microwave compatibility [3,4]. To improve barrier properties, it is necessary to control the stoichiometry and the surface morphology of the metal oxide thin films [5]. The main purpose of this research is to investigate the oxygen permeability of the AlO x thin films as a function of oxygen partial pressure. 2. Experimental procedure The AlO x thin films were deposited on a polycarbonate (PC) substrate at room temperature www.elsevier.com/locate/apsusc Applied Surface Science 249 (2005) 60–64 * Corresponding author. Tel.: +82 31 288 4499; fax: +82 31 288 4481. E-mail addresses: jinwook.seong@samsung.com, cermetal@yonsei.ac.kr (J.-W. Seong). 0169-4332/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2004.11.032