Resistive switching of Sn-doped In2O3/HfO2 core–shell nanowire: geometry architecture engineering for nonvolatile memory

Abstract

Core–shell NWs offer an innovative approach to achieve nanoscale metal–insulator–metal (MIM) heterostructures along the wire radial direction, realizing three-dimensional geometry architecture rather than planar type thin film devices. This work demonstrated the tunable resistive switching characteristics of ITO/HfO₂ core–shell nanowires with controllable shell thicknesses by the atomic layer deposition (ALD) process for the first time. Compared to planar HfO₂ thin film device configuration, ITO/HfO₂ core–shell nanowire shows a prominent resistive memory behavior, including lower power consumption with a smaller SET voltage of ∼0.6 V and better switching voltage uniformity with variations (standard deviation(σ)/mean value (μ)) of V_SET and V_RESET from 0.38 to 0.14 and from 0.33 to 0.05 for ITO/HfO₂ core–shell nanowire and planar HfO₂ thin film, respectively. In addition, endurance over 10³ cycles resulting from the local electric field enhancement can be achieved, which is attributed to geometry architecture engineering. The concept of geometry architecture engineering provides a promising strategy to modify the electric-field distribution for solving the non-uniformity issue of future RRAM.