High Temperature Oxidation of TiAlN Thin Films for Memory Devices

Abstract

TiAlN film is promising candidate as an electric barrier layer for integration of high permittivity oxides and ferroelectrics in advanced memory devices. TiAlN thin films of various compositions were prepared on poly-Si substrates by reactive magnetron sputtering. The power applied to Al target was changed to obtain the various atomic ratio of Al in TiAlN films and the oxidation behaviors of films were studied in the temperature range of 650 ∼800 using rapid thermal annealing (RTA) system. The atomic ratio of Al in TiAlN films affected the microstructure and oxidation behavior of films. The aluminum-rich oxide layer was formed on the surface of film due to the outward diffusion of Al ions during oxidation. Protective layer formed on the surface is a AlTiNO layer and this oxide layer played a role as the barrier against oxygen diffusion. Oxidation resistance of films increased with increasing the Al contents and TiAlN films were comparatively stable even at 800 . TiAlN films are very attractive barrier material for memory devices application.