MORPHOLOGY-DEPENDENT OXIDATION BEHAVIOR OF REACTIVELY SPUTTERED TITANIUM-NITRIDE FILMS

The oxidation behavior of titanium-nitride (TiN) films, which were for med at different biasing voltages, was investigated, The four film pro perties investigated (oxygen concentration, electrical resistivity, de nsity, and stress) changed monotonically with the biasing voltage. Two films with extreme biasing conditions, a dense film and a porous film , were used for a detailed investigation of oxidation behavior. The de nse film (density equal to bulk) showed a square-root-of-time growth o f the oxide layer, and its oxidation rate had an Arrhenius-type temper ature dependence with an activation energy of 2.4 eV. The porous film (density 75% of bulk) showed a time-proportional increase in resistivi ty initially, then saturation. Film composition profiling using Auger electron spectroscopy showed that the initial stage corresponds to fas t oxidation and proceeds along the gaps in the film grains; the satura tion stage corresponds to the ordinary oxidation process. The oxidatio n rates for the ordinary process were the same for both films and corr esponded to the intrinsic TiN oxidation rate. The fast oxidation rate along the gaps decreased with the oxidation time, corresponding to the so-called stuffing effect. (C) 1997 American Vacuum Society.