Improved performance of ITO/TiO2/HfO2/Pt random resistive accessory memory by nitrogen annealing treatment

Abstract Resistive switching (RS) characteristics of TiO 2 /HfO 2 bilayer memory devices annealed under N 2 and O 2 ambient were investigated in this work. It was found that the improved RS properties were obtained in N 2 annealing atmosphere, which exhibited good endurance of more than 100 times in direct current measurement mode and data retention properties of 10 4  s at 85 °C. To clarify the effect of annealing treatment on the devices in various atmospheres, conduction mechanism, which is related to the RS properties was analyzed. The results showed that the space charge limited current (SCLC) was the dominant conduction mechanism in HRS for the as prepared device; for the device annealed in N 2 , the conduction mechanism was dominated by Pool–Frenkel emission. It can be induced that the conduction mechanism variation in N 2 was attributed to the increase of oxygen vacancies in the switching layer, which was the main reason for the improvement of RS characteristics. Lastly, we switched the operation voltage from the Pt to the ITO electrode of the double layer RRAMs, and found that better endurance and smaller operation voltages were obtained when it was applied on the Pt electrode.