Re-distribution of oxygen at the interface between γ-Al(2)O(3) and TiN

Interface of TiN electrode with γ-Al(2)O(3) layers was studied using near edge X-ray absorption fine structure, conventional X-ray photoelectron spectroscopy and photoelectron spectroscopy with high energies. Despite the atomic-layer deposited Al(2)O(3) being converted into thermodynamically-stable polycrystalline cubic γ-phase by high-temperature (1000 or 1100 °C) anneal, our results reveal formation of a thin TiN(x)O(y) (≈1-nm thick) interlayer at the interface between γ-Al(2)O(3) film and TiN electrode due to oxygen scavenging from γ-Al(2)O(3) film. Formation of the TiO(2) was not observed at this interface. As environmental effect, a strong oxidation resulting in formation of a TiO(2)(1.4 nm)/TiN(x)O(y)(0.9 nm) overlayers on the top of the TiN electrode is traced. Development of O-deficiency of γ-Al(2)O(3) is observed and related to the polarization anisotropy due to the preferential orientation of spin states involved in the X-ray absorption in the plane parallel to the surface. Investigation of the TiN electrode reveals the predominantly “stretched” octahedra in its structure with the preferential orientation relative the interface with γ-Al(2)O(3). This anisotropy can be correlated with ≈200 meV electron barrier height increase at the O-deficient TiN/γ-Al(2)O(3) interface as compared to the TiN/γ-Al(2)O(3) barrier formed under abundant oxidant supply condition as revealed by internal photoemission of electrons from TiN into the oxide.