Nano-analytical investigation of the forming process in an HfO2-based resistive switching memory

International audienceMetal oxide-based resistive random access memory devices are highly attractive candidates for next-generation nonvolatile memories, butthe resistive switching phenomena remain poorly understood. This article focuses on the microscopic understanding of the initial formingstep, which is decisive for the switching process. The integrated resistive switching memory effect in Ti/HfO2/TiWN metal insulator metalstructures is studied. After forming, transmission electron microscopy investigations pointed out the presence of a funnel-shaped region, inthe ON state of the cell, where slightly oxidized Ti (TiOx) was present within HfO2 dielectric. Modeling of the measured ON state conductance of the cell with the semi-classical approximation is consistent with a conductive nanometric TiOx filament (or a sum of sub-nanometric TiOx filaments) present in the funnel-shaped region. The conductive area is likely formed by diffusion after the dielectric breakdow