High current density and nonlinearity combination of selection device based on TaO _x/TiO ₂/TaO _x structure for one selector-one resistor arrays

We demonstrate a high-performance selection device by utilizing the concept of crested oxide barrier to suppress the sneak current in bipolar resistive memory arrays. Using a TaO _x/TiO ₂/TaO _x structure, high current density over 10 ⁷ A cm ^-2 and excellent nonlinear characteristics up to 10 ⁴ were successfully demonstrated. On the basis of the defect chemistry and SIMS depth profile result, we found that some Ta atoms gradually diffused into TiO ₂ film, and consequently, the energy band of the TiO ₂ film was symmetrically bent at the top and bottom TaO _x/TiO ₂ interfaces and modified as a crested oxide barrier. Furthermore, the one selector-one resistor device exhibited significant suppression of the leakage current, indicating excellent selector characteristics.