We propose a simple and efficient model using a phenomenological fitting parameter for current-voltage sweeps to describe vacancy dynamics in oxide resistive devices, and thereby to explain the relation between physical state and resistance in these devices. The fitting parameter serves as a figure of merit, describing a device's capability for multibit operation. The understanding achieved through this model allows efficient evaluation of device performance factors including the maximum ON/ OFF ratio and the multiresistance property.
Index Terms-Copper oxide, multibit operation, vacancy.O XIDE resistive devices are well known to have the advantages of a simple structure and superior performance, and their multiple resistance properties have drawn attention to their application in future memory systems. In such applications, the ability to operate at multiple resistance levels is a key criterion representing a device's performance [1]- [5].Accordingly, physical models have been proposed to explain the multiple resistance states in bipolar oxide resistive devices during electrical operation. Most previous studies in this area [6]- [11] have concentrated on the change in the physical state during the switching processes. Among them, Yu, et al. [6] described the change in resistance according to the duration of applied voltage and Degraeve, et al. [7] explained the change in resistance using a new model they called the hour glass model. However, there is a need for a more simplified and practical model to describe the physical phenomena during electrical operation using a simple phenomenological parameter; this would allow evaluation of the performance of oxide resistive devices in terms of their multibit storage ability. Therefore, our objective in this brief is to suggest a new model that will use a simple phenomenological parameter to provide a more practical description of physical phenomena during resistance changes.For these purposes, we propose a new model based on experimental results [12] that demonstrate that the change in resistance of an oxide device is determined by the changes in current paths at the interface between the electrode and Manuscript