Non-volatile ReRAMs shown in this short course are memories with a structure in which an insulating layer is (or insulating layers are) sandwiched by metallic electrodes and the current-induced (and/or electric-field-induced) resistive switching effect is emerged. The oxide materials are widely adopted in practical use. Although the nanoionic redox process originates the non-volatile resistive switch, the change in resistance used for memory operations is huge and has a high speed; the miniaturization of ReRAMs is, in principle, possible while maintaining this high-speed change in resistance. The large amounts of works over the past decade in the area of ReRAM technology have made progress at an accelerated rate. Well-designed technologies to control the spatial distribution of oxygen ions in the ReRAM structure were developed. The stability of the operation has been improved by the control of the oxygen distribution.
In this short course, as an introduction, the historical overview of the material-based researches is provided, followed by the exposition of recent advances and the challenges of ReRAM technologies. The related topics of ReRAMs, including conductive-bridging RAM, atom switch and nanogap switch, will be also shown.