Tin-doped indium oxide (ITO) thin films were deposited on glass substrates at various oxygen flow rates using a planar magnetron sputtering system with facing targets. In this system, the strong internal magnets inside the target holders confine the plasma between the targets. High resolution transmission electron microscopy revealed a combination of amorphous and crystalline phases on the glass substrate. X-ray photoelectron spectroscopy suggested that the decrease in carrier concentration and increase in mobility were caused by a decrease in the concentration of Sn(4+) states. The electrical and optical properties of the ITO films were examined by Hall measurements and UV-visible spectroscopy, which showed a film resistivity and transmittance of 4.26 x 10(-4) Omega cm, and >80% in the visible region, respectively. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.