Using the catalytic chemical vapor deposition (Cat-CVD) method, a-Si and SiNx films have been the main focus of studies. SiO2 films have not been studied because of the limited life of catalysts such as tungsten or molybdenum in an oxidative atmosphere. In this report, we describe oxide film preparation using an iridium catalyst. We determined the most appropriate catalyst material for the oxide film process by exposing heated materials in tetraethoxysilane (TEOS) or O-2 gas. As the result, it was confirmed that the Ir catalyst works in a slow oxidative atmosphere. Using the Ir catalyst, SiO2 films were deposited in two gas combinations: TEOS and N2O, and SiH2 and N2O. Although the SiO2 film processed with the combination of TEOS and N2O was stoichiometric, its breakdown voltage is not sufficient. The SiO2 film processed with the combination of SiH4 and N2O showed good electrical property. (C) 2003 Elsevier Science B.V. All rights reserved.