Mass Production of Nanogap Electrodes toward Robust Resistive Random Access Memory

Abstract

Nanogap electrodes arrays are fabricated by combining atomic layer deposition, adhesive tape, and chemical etching. A unipolar nonvolatile resistive-switching behavior is identified in the nanogap electrodes, showing stable, robust performance and the multibit storage ability, demonstrating great potential in ultrahigh-density storage. The formation and dissolution of Si conductive filaments and migration of Au atoms is the mechanism behind the resistive switching.

Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

“…As visualisation and measurement of conductive pathways in these sandwich type structures has proven difficult, lateral device architectures have emerged in recent years as a tool for understanding filamentation [26]- [29]. Interestingly, empty lateral electrodes with separation on the nanoscale (nanogap electrodes) have also been shown to exhibit resistive switching behavior [30]- [44]. The concept of using empty nanogap electrodes as switching devices is potentially far more interesting than conventional structures, owing to the simplicity of the system from a fabrication point of view (no insulator/semiconductor material is required) and the possibility of increasing device density.…”

“…The concept of using empty nanogap electrodes as switching devices is potentially far more interesting than conventional structures, owing to the simplicity of the system from a fabrication point of view (no insulator/semiconductor material is required) and the possibility of increasing device density. The cause of switching is still debated, being attributed to either conductive filaments forming through the substrate [28], [30]- [33] or changes in the nanogap dimensions leading to different values of tunnel current [34]- [45] . The apparent bottleneck to the broad adoption of this type of approach however is the difficulty of the fabrication of nanogap electrodes at high throughput and low cost.…”

“…This has been largely true in the investigation of memristors based on nanogap electrodes, the fabrication techniques employed including electron beam lithography, electromigration and oblique angle evaporation (see Table 1 for full details). Recently, Cui et al [30] reported the use of atomic layer lithography, a scalable nanogap electrode fabrication technique reported on in recent years [47]- [49], to make arrays of Au nanogap electrodes exhibiting resistive switching effects. While promising, this remains a high temperature fabrication technique, requiring several thermal annealing steps with temperatures up to 500 °C, thus rendering it incompatible with flexible substrates.…”

Nanogap‐Engineerable Electromechanical System for Ultralow Power Memory

“…Nanogap engineering of low‐dimensional nanomaterials has the potential to fulfill this need, provided their structures and properties at the moment of gap formation could be controlled, which has been of emerging interest in a variety of fields, ranging from molecular electronics to memories 2, 5, 6, 7, 8, 9, 10. Nanogaps also have wide applications in nanoelectromechanical switching (NEMS), where electrostatic forces are used to mechanically deflect an active element into physical contact with an electrode, thus changing the state of the device 11, 12, 13.…”

Thermal robustness evaluation of nonvolatile memory using Pt nanogaps

“…[3][4][5] In a previous study, we realized the first extremely high-temperature heat-resistant memory based on a polycrystalline Pt nanogap. 6) During operation, this memory exhibits a clear on=off ratio even at 873 K. When this is used over a wide temperature range, the resistance states at different temperatures can be misidentified when the resistance is strongly dependent on temperature.…”