DOI

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.
Язык оригиналаанглийский
Номер статьи4541
ЖурналScientific Reports
Том7
Номер выпуска1
DOI
СостояниеОпубликовано - 2017

ID: 7753759