Effects of the substrate temperature on early stages of film growth were investigated for tin-doped indium oxide (ITO) films deposited on alkali-free glass substrates by dc magnetron sputtering. The variations in sheet resistance, film coverage and average surface roughness showed clearly that ITO films deposited on the unheated glass (lower than 50 degrees C) formed by a Volmer-Weber growth mode. In contrast, such an island structure was not clearly observed for films deposited on glass substrates heated at 100, 200 and 400 degrees C, resulting in better film coverage. These results indicate that the nucleation densities of ITO films increase dramatically with increasing substrate temperature. (C) 2007 Elsevier B.V. All rights reserved.