Improvement of the Parameter Distribution of TiN/HfO2/CeOx/TiN Memristors by Rapid Thermal Annealing

Abstract

TiN/HfO2/ $\text{Ce}{\text{O}}_x$ /TiN memristors were prepared by magnetron sputtering. To further improve their performance, the devices were rapidly thermally annealed at different temperatures for different times. Compared with those of unannealed devices, the coefficients of variation (CVs) of the set voltage ( $V_{\text{SET}}$ ) and the reset voltage ( $V_{\text{RESET}}$ ) were reduced by 35.1% and 59.4%, respectively, and the CVs of the resistances in low and high resistance states ( $R_{\text{LRS}}$ and $R_{\text{HRS}}$ ) were reduced by 70.2% and 52.7%, respectively, after annealing at 400°C for 2 min in air. Through X-ray diffraction, X-ray photoelectron spectroscopy, and $I‐V$ curves of the devices before and after annealing, we propose that the combined effect of grain growth (i.e., grain boundary reduction) and decreased oxygen vacancy content in the switching film resulting from annealing is responsible for the improvement in the switching parameter distribution of TiN/HfO2/ $\text{Ce}{\text{O}}_x$ /TiN devices. This work presents a simple way to enhance the performance of memristors.