Nanowire-based resistive switching memories: devices, operation and scaling

Nanowires (NWs) represent a logical pathway to extreme scaling of semiconductor devices in the single-digit nanometer scale. Combined with the inherent scalability of the resistive switching memory (RRAM), where the switching region consists of a conductive filament as small as a single atom, NWs may provide an ideal approach to reduce the device area to a range not accessible to conventional lithography. This work reviews NW-based RRAM (NWRRAM) devices. The different approaches to NWRRAMs, including (i) switching in a single metal–oxide NW, (ii) switching in a heterostructured NW with a metal–oxide segment sandwiched between NW metallic electrodes and (iii) switching in a core–shell NW, are discussed. The latter approach is then presented in detail, covering the assembly issues, the robust switching and reliability characteristics, and the scaling outlook.