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

Abstract

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.

Impact of Surface Roughness and Material Properties of Inert Electrodes on the Threshold Voltages and Their Distributions of ReRAM Memory Cells

“…10 but for Co with having a series of parallel high resistance atomic chains that add up to low overall resistance. This depiction of nanofilaments on a smooth and on rough metal surface is supported by the observations made by Wu et al 60 discussed already in the introduction. This view is further supported by the I-V characteristic of the reset operation for the Co device.…”

“…The impact of SR on the performance of resistive memory ReRAM cells has been studied for various systems in several publications. [57][58][59] An interesting observation has been made by Wu et al 60 who modified Cu surface morphology using the Cu chemical displacement technique (CDT). Using various CDT process times, Cu surface morphology with different surface roughness and different grain size could be obtained.…”

Resistive Switching Characteristics of Li-Doped ZnO Thin Films Based on Magnetron Sputtering

“…Comparing with that, the binary metal oxides have been common materials for fabricating ReRAM attributing to their simple preparing process, compatibility with integrated circuit processes, and easy to dope [11], etc. Recently, the fabrication of the metal oxide memristors mainly concentrates in ZrO 2 [12], TiO 2 [13], NiO [14], HfO 2 [15] and ZnO [16], etc.…”

Exploring the Influence of Copper Chemical Displacement Duration on Nonvolatile Oxide-based Resistive Memory Device Characteristics

“…Upon reaching the Al electrode, the Cu ions underwent reduction and reverted to atoms. (18) Consequently, a conductive filament formed between the electrodes, resulting in a sharp increase in current, and this current increased up to the compliance of the measuring system, as depicted in the right-hand section of Fig. 3.…”