Reproducible resistance switching of defect-engineered NiOx with metallic Nb impurity

Abstract The effect of Nb doping on the resistance switching characteristics of NiO x films was investigated. Pt/Nb-doped NiO x /Pt metal–insulator–metal stacks were fabricated using NiO x films with various Nb contents sputtered by reactive dc magnetron sputtering. The resistance switching behaviors of the metal–insulator–metal stacks were then examined in conjunction with a study on the physical properties such as the chemical bonding of NiO x films. Nb doping of NiO x at a T dep of 400 °C and an O 2 partial pressure of 5% resulted in an improved endurance of SET/RESET processes with a narrower distribution of V SET , and a larger memory window compared to un-doped NiO x films. NiO x with 5.47% Nb deposited at an O 2 partial pressure of 15% showed bistable resistance switching behavior while undoped NiO x material, deposited under the same condition did not. A study of the chemical bonding states by X-ray photoelectron spectroscopy showed that the Nb-doping of NiO x films produced an increase in the density of Ni 0 and a reduction in the density of Ni 3+ , compared to corresponding values for undoped NiO x films deposited under the same condition. The resistive switching behavior of NiO x was enhanced by defect engineering with metal impurity with different oxidation valence.