Tuning Resistive Switching in ZrTaO_x Devices

TaO_x chemistries have been widely studied as candidates for memristive switching memory and computation due to the non-linear conductance state transitions observed in these materials when exposed to applied electrical fields. Less effort has been put into studying the effects of doping and alloying TaO_x chemistries in order to optimize the mechanism of resistive switching. ZrTaO_x alloys offer promising properties for stable resistive switching devices due to tantalum’s mixed oxide states and zirconium’s flexible 5S outer valence bonding orbital. To explore this system, we have employed a combinatorial magnetron reactive sputtering of this Zr_xTa_1-xO_y system over a 100 mm diameter substrate and achieved a composition gradient such that 0.15<x<0.9. We confirm the composition via energy dispersive x-ray spectroscopy and generate a series of Pt/Zr_xTa_1-xO_y/Pt memristors along the gradient and correlate the resultant I-V to the composition as-deposited and as a function of annealing temperature. To gain insight into the switching mechanisms of the effective chemistries we leverage a workflow that couples conductive scanning probe microscopy (SPM) and spatially resolved time-of-flight secondary ion mass spectrometry (ToF-SIMS). Additional defects can then be introduced to these oxide systems, in the form of He, Ne and Si focused ion beams, in order to further understand how intentionally induced defects affect the oxygen motion that drives these devices.