Investigation of memory effect in Au/(Ti-Cu)Ox-gradient thin film/TiAlV structure

The paper presents the results of the analysis of resistive switching properties observed in (Ti-Cu)-oxide thin film with gradient distribution of elements over the thin film thickness. Thin films were prepared using the multisource reactive magnetron co-sputtering process. Programmed profile of the pulse width modulation coefficient during sputtering of the Cu target allowed to obtain the designed gradient U-shape profile of Cu concentration in the deposited thin film. Electrical measurements of Au/(Ti-Cu)Ox/TiAlV structure showed the presence of nonpinched hysteresis loops in the voltage–current plane testifying the resistive switching behavior. Additionally, the initial forming process of conducting filaments has been observed as well. Optical, x-ray, and ultraviolet photoelectron spectroscopy measurements allowed to create the scheme of the bandgap alignment of the prepared thin films with respect to the Au and TiAlV electrical contacts. Detailed structure and elemental profile investigations allowed to conclude about the presence of conducting filaments of the observed resistive switching mechanism occurring in the prepared test structure. The obtained results showed that the prepared gradient (Ti-Cu)Ox thin film could be an interesting alternative to the conventional multilayer stack construction of resistive switching devices.