Features and Functional Characteristics of Memristive Structures Based on Yttrium-Doped Zirconium Oxide

Characteristics of resistive switching of memristive elements based on zirconium dioxide doped with yttrium ZrO2(Y) (yttrium content 12%) were investigated. It was found that the structures are initially in a low resistivity state (LRS) and do not require forming procedure (filament formation). The memory cells demonstrate high endurance and stability of parameters during multiple switching cycles, showing more than 1010 stable switching cycles at a maximum current of 400 μA and up to 2.8 × 109 cycles at a maximum current of 1 mA. The number of statistically distinguishable resistive levels in both high-resistive (HRS) and low-resistive (LRS) states was estimated. It is shown that an increase of the maximum current to 1.2–1.5 mA does not lead to degradation of switching characteristics, which allows to obtain up to 18 statistically distinguishable levels in LRS. The phenomenon of gradual switching from HRS to LRS (gradual Set) was revealed that allows to obtain additional resistive levels in LRS.