Mechanism of High Temperature Retention Property (up to 200 degrees C) in ZrO2-Based Memory Device With Inserting a ZnO Thin Layer

Abstract

In this letter, the switching mechanism of the ZrO2-based RRAM devices with the uniform and reliable reliability properties is investigated. The stability of memory window can be improved by inserting a ZnO thin film with the nonstoichiometric property between Ti top electrode and ZrO2 layer. Compared with ZrO2 film, the ZnO one can easily perform the oxidation-reduction reaction for stable endurance properties. In addition, through Gibbs free energy comparison of TiOx, ZrO2, and ZnO, we can demonstrate that the Gibbs free energy contributes to the retention performance. The device with thin ZnO layer has stable retention performance at high temperature (200 degrees C) due to its higher Gibbs free energy value than TiOx.