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TiO 2 thin films prepared by atomic layer deposition (ALD) have attracted great attention due to the widespread application of the oxide as a promising charge storage material for lithium or proton batteries. In this work, we study TiO 2 film grown on Si substrates by atomic layer deposition with tetrakis (dimethylamino) titanium as metal precursor (TDMAT) and water vapour as an oxidant. The chemical composition and impurity content of the film as a function of growth temperature is studied by Ion Beam Analysis (IBA). D 2 O (99.8%) was used as oxidant to study the film growth to distinguish between hydrogen atoms originating from the water oxidant or the metal precursor. Combining ellipsometry with Rutherford Backscattering Spectrometry (RBS), Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA) reveals film density as a function of growth temperature. Atomic force microscopy (AFM) was used to characterize the film surface structure. By investigating the structural and compositional range of ALD TiO 2 films will open the new opportunities of application. In this work, we study TiO 2 film grown on Si substrates and bare Cu by atomic layer deposition with tetrakis (dimethylamino) titanium as metal precursor and water vapour as oxidant. The chemical composition and impurity content of the film as a function of growth temperature is studied by Ion Beam Analysis (IBA). D 2 O (99.8%) was used as oxidant to study the film growth to distinguish between hydrogen atoms originating from the water oxidant or the metal precursor. Combining ellipsometry with RBS, NRA, and ERDA reveals the film density as a function of growth temperature. Atomic force microscopy (AFM) was used to characterize the film surface structure.According to the composition and structure study, we here deposited ALD TiO 2 films on the copper as a function of deposition temperature, the Tafel polarization and electrochemical impedance spectroscopy (EIS) were used to study the anti-corrosion properties of ALD TiO 2 film coated on the copper in the 3.5% (0.6 M) NaCl solution. We proposed the H atoms in the TiO 2 films (100 °C) and the rough structure (225 and 300 °C) determine the corrosion behaviors. [Display omitted] • We explored the impurity content and in particular the carbon, nitrogen and hydrogen areal density in ALD TiO 2 film. • Isotope labelling confirmed that the vast majority of H atoms originated from the metal precursor. • The H atoms in the TiO 2 films (100 °C) could alleviate the barrier of charge transfer, high deposition temperature results in a high electron transfer resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Equal TMDAT/water half cycles for ALD TiO 2 deposition give unexpected outcomes in the 100 °C-300 °C deposition temperature range. • Almost exclusively TiIV oxidation state throughout the 100 °C-300 °C temperature window. • Amorphous high H content, O/Ti < 2, valence band edge tails and gap states for 100 °C deposition temperature. • Lower H content crystalline films with O/Ti ∼ 2, no gap states for 225 °C deposition temperature and above. • Ligand exchange reaction byproducts confined to the oxide surface. • n – type oxides for all deposition temperatures. • Combined IBA and XPS are powerful tools to optimize ALD processes. Titania films prepared by atomic layer deposition attract great attention due to the widespread application of the oxide as a photocatalytic material, or more recently, as a promising charge storage material for lithium or proton batteries. We implement here advanced tools (Ion Beam Analysis and X-ray Photoelectron Spectroscopy, aided by Ellipsometry and X-ray Diffraction) to characterize films grown in the 100 °C-300 °C temperature window, using tetrakis(dimethylamino)titanium (TMDAT) as the metal precursor and water vapor as the oxidant. We examine the outcomes of the ALD process as a function of the deposition temperature, applying equal oxidant and precursor half-cycle time lengths, which contrasts with common deposition processes where the water half-cycle is considerably shorter than that of the metal precursor. Under the present ALD scheme, n -type conductive films are obtained where the oxidation state of titanium is overwhelmingly TiIV at all temperatures, while the hydrogen content (O/Ti ratio) varies considerably, from ∼ 15 at% (∼1.8) at 100 °C to ∼ 3 at% (∼2) at 300 °C. The ideality of the ALD process is discussed through the identification of nitrogen-containing molecules detected at the oxide surfaces. By extending the structural and compositional range of ALD titania films, new opportunities of application are expected to appear. [ABSTRACT FROM AUTHOR]