Quantized conductive filament formed by limited Cu source in sub-5nm era

For the first time, we have investigated the resistive switching characteristics in extreme size (sub-5nm) device. Less than 5nm effective electrode radius is confirmed by conductive-AFM and FIB-TEM analysis. The conductive filament source (Cu ions) is limited by applying novel fabrication technology. Due to the limited Cu source, we observe the quantized formation of conductive path, which results in the distinguishable conductance states and shows the feasibility of multi-bit operation. By controlling the motion of Cu ions precisely, ideal selection behavior for xpoint memory application was achieved.