Investigation of resistive switching properties in reliable, forming-free RRAM devices based on amorphous Sm2Zr2O7 thin films

The resistive switching (RS) behavior of amorphous Sm₂Zr₂O₇ thin films was investigated for their potential application in resistive random-access memory (RRAM) devices. The devices were fabricated using indium tin oxide (ITO)-coated glass as the bottom electrode and aluminum (Al) as the top electrode. All devices exhibited forming-free behavior, likely attributed to the defective fluorite structure of the Sm₂Zr₂O₇ compound. The RS properties were further optimized through appropriate annealing processes, which generated additional oxygen vacancies. Moreover, a post-metal annealing treatment formed an AlO_x interface layer, significantly enhancing the RS performance. The sample subjected to a 300 °C PMA treatment demonstrated reliable operation for up to 1606 cycles, achieving a high R_on/R_off ratio of approximately ∼10³ under SET/RESET voltages of 1.43 V and 0.42 V, respectively, with retention stability lasting for 10⁴ s at both room temperature and 85 °C. These findings highlight that Sm₂Zr₂O₇, combined with intrinsic properties and appropriate thermal treatments, is a promising candidate for low-temperature, CMOS-compatible non-volatile RRAM applications.