Effect of anodic interface layers on the unipolar switching of HfO2-based resistive RAM

In this work, the effect of the anode electrode-HfO₂ interface on unipolar switching for HfO₂-based RRAM is systematically investigated. It is found that the switching behavior can be improved not only by changing the anode electrode material (TiN vs. Pt), but also by engineering the anodic interface with thin M or MO_x capping layers between the electrode and the HfO₂ film, such as Ti or TiO. The relative stability of oxide formation, as expressed by the thermodynamic parameter, Δ_fG (molar Gibbs energy of oxide formation), is introduced in this work to understand those different switching behaviors more directly.