Advanced Cu chemical displacement technique for SiO2-based electrochemical metallization ReRAM application

et al. 2018

Materials

Self Cite

Electrochemical-metallization-type resistive random access memories (ReRAMs) show promising performance as next-generation nonvolatile memory. In this paper, the Cu chemical displacement technique (CDT) is used to form the bottom electrode of ReRAM devices. Compared with conventional deposition methods, the Cu-CDT method has numerous advantages for ReRAM fabrication, including low cost, low temperature fabrication, and the provision of unconsolidated Cu film and large surface roughness. Moreover, the Cu-CDT method is a favorable candidate for overcoming the Cu etching problem and is thus suitable for fabricating ReRAM devices. Using this technique, the surface morphology of a thin Cu film can be easily controlled. The obtained results show that the electric fields during the Forming and SET operations decreased, and the on-state current increased in the RESET operation, as the Cu-CDT displacement time was increased. The Cu-CDT samples exhibited a low operation field, large memory window (>106), and excellent endurance switching cycle characteristics. Moreover, this paper proposes a model to explain the electrical characteristics of ReRAM, which are dependent on the surface morphology.

Section: Introductionmentioning

confidence: 99%

Impact of Electrode Surface Morphology in ZnO-Based Resistive Random Access Memory Fabricated Using the Cu Chemical Displacement Technique

You

et al. 2018

Materials

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“…Several transition metal oxides (TMOs), such as TiO 2 , NiO, Ta 2 O 5 , and HfO 2 , have been tested as RS layers because the multi-valence nature of the transition metals would render the RS in these materials easily achieved 1 2 3 4 . Additionally, the so-called voltage-time dilemma from typical RS materials triggered interest in finding alternative RS materials, and several groups had tested SiO 2 5 6 7 . Due to the mostly ionic bonding in the TMO RS materials, electric-field-driven ion migration is easier when the material contains an appropriate density of ionic defects.…”

mentioning

confidence: 99%

Bias-polarity-dependent resistance switching in W/SiO2/Pt and W/SiO2/Si/Pt structures

Jiang

Chen

et al. 2016

Sci Rep

SiO2 is the most significantly used insulator layer in semiconductor devices. Its functionality was recently extended to resistance switching random access memory, where the defective SiO2 played an active role as the resistance switching (RS) layer. In this report, the bias-polarity-dependent RS behaviours in the top electrode W-sputtered SiO2-bottom electrode Pt (W/SiO2/Pt) structure were examined based on the current-voltage (I-V) sweep. When the memory cell was electroformed with a negative bias applied to the W electrode, the memory cell showed a typical electronic switching mechanism with a resistance ratio of ~100 and high reliability. For electroforming with opposite bias polarity, typical ionic-defect-mediated (conducting filament) RS was observed with lower reliability. Such distinctive RS mechanisms depending on the electroforming-bias polarity could be further confirmed using the light illumination study. Devices with similar electrode structures with a thin intervening Si layer between the SiO2 and Pt electrode, to improve the RS film morphology (root-mean-squared roughness of ~1.7 nm), were also fabricated. Their RS performances were almost identical to that of the single-layer SiO2 sample with very high roughness (root-mean-squared roughness of ~10 nm), suggesting that the reported RS behaviours were inherent to the material property.

“…When the conductive filaments connecting both electrodes, the resistance was transformed to LRS (on state). By contrast, a negative voltage bias induced the electrochemical dissolution of the metal filaments (off state) .…”

Section: Resultsmentioning

confidence: 99%

A novel nanoscale‐crossbar resistive switching memory using a copper chemical displacement technique

Yang

Physica Status Solidi (a)

et al. 2016

Self Cite

Nanoscale‐crossbar electrochemical‐metallization (ECM) type resistive‐switching random access memory (ReRAM) is considered promising candidates for next‐generation non‐volatile memory. However, performing nanoscale patterning with traditional Cu‐based ECM ReRAM is quite challenging, because Cu is difficult to control and pattern using lithography and etching. In this study, a nanoscale Cu‐based ReRAM with a Si3N4–SiO2 bi‐layer was fabricated successfully through a novel Cu chemical displacement technique (Cu‐CDT). Compared with other conventional Cu deposition techniques, the Cu‐CDT exhibits numerous advantages including simplicity, low‐temperature fabrication, low cost, and high displacement selectivity between poly‐Si and the Si3N4–SiO2 bi‐layer. Moreover, the developed nanoscale‐crossbar Cu‐CDT ReRAM device demonstrated stable switching and remarkable high‐temperature data retention. Therefore, the Cu‐CDT is an effective approach for overcoming Cu etching and patterning limitations.