Reliability/Uniformity improvement induced by an ultrathin TiO2 insertion in Ti/HfO2/Pt resistive switching memories

• Reliability of resistance switching was improved by inserting an TiO2 interfacial layer.
• TiO2 limits the disorder migration of oxygen and provides more chemically-stable interfaces.
• Random variation during endurance test was greatly limited in Ti/TiO2/HfO2/Pt memory.

Reliability/Uniformity of resistance switching in Ti/HfO2/Pt memory structure was improved by inserting an interfacial layer of 5 nm-thick TiO2 between Ti and 45 nm-thick HfO2. As a native oxide of Ti, TiO2, effectively limits the disorder migration of oxygen from HfO2 to Ti layer, and provides the more chemically-stable and morphologically-uniform interfaces with both the Ti electrode and the HfO2 layer. Meanwhile, more stable resistive switching was observed in Ti/TiO2/HfO2/Pt than that in Ti/HfO2/Pt memory, and the random variation during endurance test observed in Ti/HfO2/Pt was also greatly limited in Ti/TiO2/HfO2/Pt memory. From these results, a thin TiO2 insertion between the Ti electrode with the HfO2 active layer, could greatly improve the reliability/uniformity of the Ti/HfO2/Pt memory devices.