The AIO(x) thin films were deposited on the polycarbonate by reactive ion beam sputtering (RIBS) at different oxygen partial pressures where the AlOx thin film with O/Al ratio of 1.5 was formed when oxygen partial pressure increased from 4 x 10(-5) to 2 x 10(-4) 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. (c) 2004 Elsevier B.V. All rights reserved.