Oxidation and structural changes in fcc TiNx thin films studied with X-ray reflectivity

The evolution of oxidation process at room temperature of thin fee titanium nitride (TiNx) films grown by DC reactive magnetron sputtering was studied by X-ray reflectivity (XRR) measurements and supported with in situ spectroscopic ellipsometry (SE) measurements. Precise thin-film thickness and density as well as surface roughness were determined from X-ray specular reflectivity data analysis. The XRR measurements were conducted with a conventional diffractometer equipped with a Gobel mirror and a special reflectivity sample stage. The XRR results obtained from the TINx films during exposure to air show an exponential increase in density and thickness and a decrease in the value of RMS surface roughness. Analysis of the SE results shows that oxidation takes place in the hulk of the TiNx film transforming it to titanium oxide. The percentage of transformation and the type of the oxide depends on the TiNx film stoichiometry. The above structural and compositional changes are consistent with the evolution of stress (compressive) measured in the TINx films during exposure to air by cantilever technique. (C) 1998 Elsevier Science S.A.