A Mechanistic Analysis of Oxygen Vacancy Driven Conductive Filament Formation in Resistive Random Access Memory Metal/NiO/Metal Structures

Study could lead to more efficient electrically switchable resistive random access memory devices.

Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio

Resistive Random Access Memory (RRAM) devices have drawn much interest in the last decade, particularly the concept of a memristor. In this case, the so-called memristance, which provides the relationship between the change in charge (time integral of the current) and flux (time integral of the voltage), is not a constant as in linear elements, but a function of the charge, resulting in a nonlinear circuit element. Applications of such two-terminal electrical devices that provide high densities and low-power operation include, for instance, neuromorphic-type computing elements.

This area of research led to a study on the effects of ionizing radiation on such devices. Significant focus on filamentary- type resistive switching (RS) mechanisms emerged, where formation/rupture of a conductive filament (CF) ensures successive switching in the nonvolatile metal-insulator-metal (MIM) memristors, dependent on the switching material. In such a RRAM device, binary oxide MIM structures are constructed using an insulating layer stacked between two electrodes, which can be built either symmetrically or asymmetrically using the same or different top or bottom electrodes, respectively.