Abnormal bipolar resistive switching behavior in carbon-iron composite films with different thicknesses

Carbon-iron composite films with different thicknesses (50, 100 and 150 nm) were deposited by DC magnetron sputtering method using a composite target (Fe: 4 at%, C: 96 at%). The resistive switching behaviors of Pt/Al/a-C:Fe/Au/Ti structures with different a-C:Fe film thicknesses are investigated. Abnormal bipolar resistive switching characteristics were observed in all Pt/Al/a-C:Fe/Au/Ti memory cells. Considering the endurance and retention properties, the RRAM cell with 100 nm thick a-C:Fe film as the dielectric layer showed the best performance with on/off-resistance ratio ∼10, and retention time >104 s. Based on the results of the X-ray photoelectron spectroscopy depth profile, the resistive switching behavior is attributed to mutative Al3+ fraction at the Al/a-C:Fe interface and the migration of Au ions between two electrodes.