Influence of the plasma oxidation power on the switching properties of Al/CuxO/Cu memristive devices

In this study, CuxO memristive devices have been fabricated that exhibited the unique property of complete nonpolar switching behavior. Complete nonpolar switching is not frequently reported in memritisve devices, rather a single bipolar and unipolar curve is reported. The CuxO was created via plasma oxidation under varying reactive ion etch (RIE) power levels, ranging from 100 to 300 W. The resulting CuxO thin films ranged in thickness from 40 nm to 620 nm as determined by secondary ion mass spectrometry (SIMS) analysis. X-ray photoelectron spectroscopy (XPS) analyses also indicated that the Cu:O atomic ratios of these films increased from 1:1 to 3:2 with increasing RIE power. The SET and RESET voltages were ±2–3 V and ±0.3–0.7 V, respectively. High to low resistance state ratios up to 4,000 were observed and demonstrated dependence upon both oxide thickness and oxygen concentration. An analysis of the current conduction in the high and low resistance states is also given.

► Complete nonpolar switching reported for Al/CuxO/Cu memristive devices.
► Reactive ion etch power affects oxygen concentration and thickness of CuxO films.
► These properties in turn affect the highest resistance of fabricated memristors.
► Device conduction observed to be Ohmic and occasionally Poole–Frenkel emission.