Electrical properties of resistive switches based on Ba$_{1 -x}$Sr$_{x}$TiO$_{3}$ thin films prepared by RF co-sputtering

Abstract

In this work, we propose the use of Ba$_{1-x}$Sr$_{x}$TiO$_{3 }$(0 $ \le $ x $ \le $ 1) thin films for the construction of MIM (metal-insulator-metal) heterostructures; and their great potential for the development of non-volatile resistance memories (ReRAM) is shown. The deposition of Ba$_{1-x}$Sr$_{x}$TiO$_{3}$ thin films was done by the rf co-sputtering technique using two magnetron sputtering cathodes with BaTiO$_{3}$ and SrTiO$_{3}$ targets. The chemical composition (x parameter) in the deposited Ba$_{1-x}$Sr$_{x}$TiO$_{3}$ thin films was varied through the rf power applied to the targets. The constructed MIM heterostructures were Al/Ba$_{1 - x}$Sr$_{x}$TiO$_{3}$/nichrome. The I-V measurements of the heterostructures showed that their hysteretic characteristics change depending on the Ba/Sr ratio of the Ba$_{1-x}$Sr$_{x}$TiO$_{3}$ thin films; the Ba/Sr ratio was determined by employing the energy dispersive spectroscopy; SEM micrographs showed that Ba$_{1-x}$Sr$_{x}$TiO$_{3 }$thin films were uniform without cracks or pinholes. Additionally, the analysis of the x-ray diffraction results indicated the substitutional incorporation of Sr into the BaTiO$_{3}$ lattice and the obtainment of crystalline films for the entire range of the x values.