Titanium nitride (TiN) thin films were deposited by dc magnetron sputtering on SiO2/n-Si substrates in order to study their use as gate electrodes in metal–oxide–semiconductor (MOS) devices. Rutherford backscattering spectroscopy was used to determine the composition of the films and the results were correlated to those obtained by electrical measurements of the constructed MOS devices. Oxygen contamination of the TiN layers was observed, with percentage and spatial variations depending on the various deposition parameters such as the deposition temperature and the substrate bias. The best electrical performance was achieved for devices where the exposed TiN surface had low oxygen contamination. From these samples, the TiNx–Si barrier height was calculated to be equal to 0.52 eV. © 2000 American Institute of Physics.