Effects of Al dopants and interfacial layer on resistive switching behaviors of HfOx film

In this work, Al dopants were introduced into HfOx film by different methods to modulate the oxygen vacancies in the film or near the interface, and the resistive switching characteristics were investigated. By transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis, an interfacial layer was formed at HfOx/Al interface. The occurrence of interfacial layer resulted in the larger switching voltages and resistances in LRS for HfOx/Al/HfOx and HfOx/Al samples compared with HfOx:Al sample with uniform Al dopants and no interface. Besides, the different reset processes for Al-doped HfOx samples were demonstrated. Much uniform distribution of resistances can be observed for all Al-doped HfOx samples due to the control of oxygen vacancies by Al doping and the good retention properties were achieved for all samples. The models for underlying physical mechanisms were also proposed to illustrate the switching behaviors of the prepared samples. © 2017 Elsevier B.V.