Formation, Phase Composition and Memristive Properties of Titanium Oxide Nanodots

The increase in the modern electronics productivity is limited by the CMOS structures minimum size. Further miniaturization is impossible due to an increase in leakage current. Therefore, increasingly attention is paid to the development and research of new nanoelectronic elements with small characterizing dimensions, as well as high performance and speed. In this case, the resistive switching effect is achieved due to the formation of oxide nanostructures with a controlled stoichiometric composition. The local anodic oxidation method is the most promising method for memristor formation since the resulting structures exhibit the forming-free memristor effect and can be used as memory elements, as well as for performing logical operations. In this work, the titanium oxide nanodots arrays formation was carried out at various parameters and the structures geometric dimensions dependences on the applied voltage amplitude and duration pulse were obtained. A current-voltage characteristics study of nanodots showed that the resulting structures switch between the high(140 GΩ) and low(1.7 GΩ) resistance states. Furthermore, we performed a numerical simulation of the formation of oxide nanodots obtained by the local anodic oxidation method, the results of which showed that the TiO₂ phase dominates on the formed oxide surface. As the oxide goes deeper into the bulk, the Ti₂O₃ and TiO phases appear, and the TiO phase prevails near the metal/oxide interface. To confirm the simulation results, the titanium oxide nanodots phase composition was studied by the XPS method, which confirmed the theoretical results. The results can be used in the development of technological processes for the formation of elements of nanoelectronics, as well as elements of resistive memory based on oxide nanoscale structures. The reported study was funded by RFBR, according to the research project No. 19-29-03041_mk, and by grant of the President of the Russian Federation No. MK-767.2020.8.