Amorphous ITO thin films were deposited on silicon wafers at room temperature by RF+DC magnetron sputtering at water vapor partial pressures between 0 and 6 x 10(-5) Torr. The O/(In + Sn) ratio was determined by Rutherford backscattering spectroscopy. The effect of water vapor on the thermal crystallization process was monitored by high-temperature X-ray diffraction (XRD) analysis. We found a simple dependence between the crystallization temperature and the water vapor partial pressure. After the high-temperature XRD, the films deposited at low water vapor pressures (2 x 10-5 Torr or lower) exhibited (100) preferred orientation, whereas those deposited at high water vapor pressures (3 x 10(-5) Torr or higher) exhibited (111) preferred orientation. Introduction of water vapor during the deposition decreased carrier concentration and increased mobility. The carrier concentration after thermal crystallization was dependent on the water vapor partial pressure. (C) 2007 Elsevier B.V. All rights reserved.