Effect of the top electrode materials on the resistive switching characteristics of TiO2 thin film

Abstract

Various metals, such as Pt, stainless steel (SUS), Al, Ni, and Ti, were used as a top electrode (TE) to evaluate the dependency of the resistive switching characteristics on the TE of the metal/TiO2/Pt structure. The variation of the chemical composition of TiO2 in the metal/TiO2/Pt structure before and after switching was examined to identify the factors affecting the resistive switching characteristics of the samples with various TE materials. In the case of TE/TiO2/Pt structures showing unstable resistive switching behavior, e. g., those with the Al, Ni, and Ti TEs, secondary ion mass spectrometry revealed an increase in the oxygen concentration at the interface area between the TE metal and TiO2. This suggests that the oxidation reaction at the interface between the TE metal and TiO2 might cause the TE/TiO2/Pt structure to exhibit unstable resistive switching characteristics. According to these results, the oxidation reaction at the interface between the metal TE and TiO2 thin film is a primary factor affecting the resistive switching characteristics of TiO2-based Resistive Random Access Memory devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3596576]