Hafnium nitride films were prepared on the Si(100) substrates by the metal-organic chemical vapor deposition method using Hf [N (C2 H5) 2] 4. The prepared samples were then oxidized in air, followed by rapid-thermal annealing to produce Hf Ox Ny thin films, meanwhile the associated physical properties were investigated. The x-ray photoelectron spectroscope analysis unveiled that the composition of the films is Hf Ox Ny. In addition, the films after the rapid-thermal annealing treatments at various temperatures revealed salient features in their physical properties, such as capacitance and conductivity. On this basis, the feasibility of using the Hf Ox Ny layers as high- k dielectrics in complementary metal oxide semiconductor transistors was also discussed.