Highly repeatable multilevel resistive switching characteristics of an Au/TiO2/Ti memory device

Abstract

Development of a highly repeatable multilevel resistive switching Au/TiO2/Ti memory device is reported in this paper. Undoped rutile TiO2 thin film, having a thickness of 480 nm, was grown on high-purity Ti (99.5%) by in situ thermal oxidation technique at 600 °C. Au metal contact was used as a top electrode. The developed Au/TiO2/Ti memory device was electrically characterized for resistive random access memory applications and found to have extremely repeatable, reproducible and stable bipolar resistive switching characteristics. With very low ‘SET’ and ‘RESET’ voltage requirement, the device offered highly symmetric multilevel high- to low-resistance state transitions. The two pairs of ‘SET’ and ‘RESET’ voltages were ±0.26 V and ±0.64 V. As there is no requirement of electroforming voltages, low electric field operation of the device is ensured, which eventually leads to the avoidance of high field hazards. The effect of operating temperature on the performance of Au/TiO2/Ti memory devices was also investigated in the temperature range of 27–80 °C, and the device offered negligible shift in the characteristics, ensuring high-temperature stability. The multilevel switching phenomenon was explained by appropriate defect models.