Impact of thermal treatments on resistive switching properties of Y₂Ti₂O₇ thin films prepared by RF sputtering

This study investigates the resistive switching (RS) properties and performs impedance analysis of thin film RRAM devices made of Y₂Ti₂O₇ (YTO), prepared using RF sputtering. The research focused on the effects of film thickness, deposition atmosphere (Ar/O₂), top electrodes, and particularly thermal treatments on RRAM performance. All samples displayed bipolar resistive switching (BRS) behavior, with the conduction mechanism following ohmic conduction at a low resistance state (LRS) and space charge limited conduction (SCLC) at a high resistance state (HRS). The oxygen vacancy concentration of the YTO film can be optimized through the post-annealing process. Furthermore, the post-metallization annealing (PMA) treatment can further improve the resistive switching properties, which enhances the formation of an AlO_x interface layer. This layer also helps prevent the out-diffusion of oxygen ions across the boundaries. With a PMA treatment at 300 °C, the Al/Y₂Ti₂O₇/ITO RRAM device was able to achieve 2491 switching cycles, with a low V_set/V_reset of − 1.5/0.91 V and a distinguishable memory window of R_on/R_off > 10¹.