Resistive switching (RS) is an interesting property shown by some materials systems that, especially during the last decade, has gained a lot of interest for the fabrication of electronic devices, with electronic nonvolatile memories being those that have received the most attention. The presence and quality of the RS phenomenon in a materials system can be studied using different prototype cells, performing different experiments, displaying different figures of merit, and developing different computational analyses. Therefore, the real usefulness and impact of the findings presented in each study for the RS technology will be also different. This manuscript describes the most recommendable methodologies for the fabrication, characterization, and simulation of RS devices, as well as the proper methods to display the data obtained. The idea is to help the scientific community to evaluate the real usefulness and impact of an RS study for the development of RS technology.

The basic unit of information in filamentary-based resistive switching memories is physically stored in a conductive filament. Therefore, the overall performance of the device is indissolubly related to the properties of such filament. In this Letter, we report for the first time on the three-dimensional (3D) observation of the shape of the conductive filament. The observation of the filament is done in a nanoscale conductive-bridging device, which is programmed under real operative conditions. To obtain the 3D-information we developed a dedicated tomography technique based on conductive atomic force microscopy. The shape and size of the conductive filament are obtained in three-dimensions with nanometric resolution. The observed filament presents a conical shape with the narrow part close to the inert-electrode. On the basis of this shape, we conclude that the dynamic filament-growth is limited by the cation transport. In addition, we demonstrate the role of the programming current, which clearly influences the physical-volume of the induced conductive filaments.

No abstract

In this paper, we optimize the stack of a 90-nm CMOS-friendly W\Al 2 O 3 \Cu conductive-bridging random access memory cell integrated in the one-transistor/one-resistor configuration. We show that the excellent Cu buffering properties of a TiW layer inserted at the Al 2 O 3 \Cu interface make it possible, on one hand, to ensure cell integrity after back-endof-line processing at 400°C and, on the other, to obtain excellent memory performances. After optimization of the Al 2 O 3 layer thickness, the cell exhibits highly controlled set and reset operations, a large memory window, fast pulse programming (10 ns) at low voltage (<3 V), and low-current (10 µA), and multilevel operation. Finally, 10 6 cycles of write endurance lifetime with up to a three-decade memory window is demonstrated, and state stability is assessed up to 125°C.Index Terms-Conductive bridging, conductive-bridging random access memory, electrochemical memory cell (ECM), high-performance memory, low-power memory, thermal stability.

No abstract

No abstract

No abstract

The formation and rupture of conductive filaments (CFs) inside an insulating medium is used as hardware encoding of the state of a memory cell ("1" - "0") in filamentary-based conductive bridging memories. Currently accepted models explain the filament erase (reset) as the subtraction of conductive metal atoms from the CF; however, they do not fully account for the rich set of phenomena experimentally observed during the reset. The details of the filament erase are unraveled on the nanometer scale by means of an atomic force microscopy-based tomography technique enabling the 3D observation of erased CFs. "Non-broken" and "broken" CFs are observed, whereby the increase in resistance originates, respectively, from a constriction point in the current path and from an interrupted CF. We demonstrate that their existence and morphology can be related to the specific formation history of the CF, and we identify the physical volume of the CF as being mainly responsible for the type of filament erase.