Moreover, the resistivity was found to decrease by more than 3 orders after annealing at 673K. Such changes in the resistivity of the films may be due to the change of crystal structure of the films, but was not clear. Because the XRD patterns of the as-deposited films showed only one vague peak, it would not be appropriate to identify the crystal structure of the as-deposited films from the X-ray diffraction (XRD) analysis. Therefore, in this study, we systematically investigated the electrical properties of Fe-O-N films deposited by reactive sputtering by widely changing O2 (0.050.25sccm) and N2 (05sccm) gas flow rate, and the relationships between electrical properties and crystal structure of the Fe-O-N films were discussed based on not only XRD measurements but also transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) analysis and temperature dependence of the resistivity of the films.