Thin films of titanium nitride (TiN) were obtained by annealing Ti films in nitrogen atmosphere for different times. An accurate characterization of their chemical and crystalline nature was performed using X-ray photoelectron spectroscopy (XPS) depth profiling and X-ray diffraction (XRD) measurements. The XPS results show a deeper penetration of the nitrogen into the titanium layer as the forming time increases and a non-stoichiometric composition of the TiN layer when the nitridation time of the titanium him at 585 degrees C is below 100 min. The XRD data of these samples indicate the presence of a mixture of different crystalline phases.