Indium tin oxide (ITO) films prepared by dc magnetron sputtering were. annealed in air, vacuum, and oxygen gas atmospheres. The electrical properties and internal stresses of these annealed ITO films were systematically investigated. It was found that, among the above postannealing treatments, oxygen gas annealing significantly reduced both the resistivity and the internal stress in ITO films at fairly low temperatures of 100-150 degreesC. Resistivities and internal stresses as low as 7 x 10(-4 Omega) cm and 38 MPa, respectively, were obtained by annealing in oxygen gas atmosphere at 100degreesC. It was also revealed that the (111) crystal orientation becomes dominant and that whole grains grow dramatically as a result of postoxygen annealing, even at 100 degreesC. (C) 2003 American Vacuum Society.