전기화학적법으로 합성한 Au-NiO-Au 나노와이어 저항스위칭 현상 이해와 ReRAM 적용

Abstract

Resistive switching random access memory (ReRAM) has been studied in the form of metal-oxide-metal structures for future nonvolatile memory because of its low power consumption and high scalability between different resistance states. In recent days, various types of materials are fabricated for ReRAM not only transition metal oxide but semiconducting or organic materials. Oxide systems like NiO and TiO2 are promising candidate materials for ReRAM because they are easy to fabricate and have low operation current. Each material has preferred operation model. For example, TiO2 usually shows bipolar switching mode and NiO shows unipolar mode. And it is possible that different mechanisms may coexist. Different mechanisms could be dominant in different material systems-filament model for unipolar mode and interface model for bipolar mode. Many researchers proposed that a redox process in the anode interface plays an important role in a resistive switching mechanism especially in bipolar system. Among several methods controlling the redox process, doping of impurity impacts on the behaviors of oxygen vacancies. However, influences of doping on a transient metal oxide have been rarely studied. In this study, Au/NiO/Au segmented nanowires are synthesized by electrochemical deposition method and investigated the resistive switching behaviors. Nano-sized oxide layer could enhance the surface to volume ratio and could control the filament effectively. Further, the effort has been made to understand the properties at the interface between the metal and insulator by doping phosphorus into NiO. Doped phosphorus changes Ni/O ratio and it shows switching transition from unipolar to bipolar.