An Efficient Method Based on Tuning Ions Transport Path to Improve Resistive Switching Performance in HfO ₂ -Based Devices

The distribution and composition of elements and defects in the resistive switching (RS) layer are the critical factors contributing to the performance of the resistive random access memory (RRAM). In this work, the influence of the distribution and number of oxygen vacancies on the migration of Ag<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and performance of the Ag/HfO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>/fluorine-doped tin oxide (FTO) devices was studied by controlling the annealing temperature and electrical preforming (PF) process. The elemental analysis and chemical characterization were confirmed by XPS and XRD. The device showed the low <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>SET</roman></sub>, high resistance state (HRS)/low resistance state (LRS) ratio and analog-type RS behavior after the annealing process. Multilevel conductance modulation was also realized by applying various negative voltages to the devices, which demonstrates the application of high-density data storage. XPS and electrical analyses reveal that the controlled formation and rupture of the filament, composed of oxygen vacancy and Ag, along with the charged space-charge region, are responsible for the RS characteristics of the prepared devices. The work shows that the annealing process combined with electrical PF significantly enhances the performance of memory devices.