Characterization and oxidation kinetics of reactively sputtered T_1-xAl_xN film

We report on the use of Ti_1-xAl_xN as an electrically conductive barrier layer from the viewpoint of its oxidation kinetics and electrical properties. Auger electron spectroscopy depth profile analysis revealed the improvement of oxidation resistance with Al incorporation. At 650 °C, an oxygen diffusion coefficient and an activation energy of Ti_0.47Al_0.53N were determined to be 5.85×10^-1 A²/sec and 2.51 eV respectively. Compared with TiN, this corresponds to an oxide growth rate reduction of about two orders of magnitude. An Al-rich oxide layer, which grew near the Ti_1-xAl_xN surface, is believed to act as a passivation layer to oxidation. Furthermore, currentvoltage characteristics showed that the oxidation resistant Ti_1-xAl_xN minimized the increase of electrical resistance after heat treatment in an oxidizing atmosphere. These results suggest that Ti_1-xAl_xN is an attractive candidate for an electrically conductive barrier layer for advanced memory device applications.