Low-power switching of nonvolatile resistive memory using hafnium oxide

Nonstoichiometric hafnium oxide (HfO_x) resistive-switching memory devices with low-power operation have been demonstrated. Polycrystalline HfO_x (O : Hf = 1.5 : 1) films with a thickness of 20 nm are grown on a titanium nitride (TiN) bottom electrode by commercial atomic layer deposition. Platinum (Pt) as a top electrode is used in the memory device. Voltage-induced resistance switching is repeatedly observed in the Pt/HfO_x/TiN/Si memory device with resistance ratio is greater than 10. During the switching cycles, the power consumptions for high- and low-resistance states are found to be 0.25 and 0.15 mW, respectively. At 85°C, the memory device shows stable resistance switching and superior data retention with resistance ratio is greater than 100. In addition, our memory device shows little area dependence of resistance-switching behavior. The anodic electrode containing noble metal Pt serves an important role in maintaining stable resistance switching. The resistance switching in the HfO_x films is thought to be due to the defects that are generated by the applied bias. The nonstoichiometric HfO _x films are responsible for the low SET and RESET currents during switching. Our study shows that the HfO_x resistive-switching memory is a promising candidate for next-generation nonvolatile memory device applications.