Highly Improved Switching Properties in Flexible Aluminum Oxide Resistive Memories Based on a Multilayer Device Structure

Multilayer aluminum oxide (Al2O3) resistive memory devices, exhibiting robust switching properties fabricated on a flexible polyethylene naphthalate substrate using only physical vapor deposition methods at room temperature, are reported here. Improved reliability and robust switching properties of the multilayer Al2O3 memory devices are observed compared to those of the single-layer devices, with the assistance of a guide filament formed in the bottom Al2O3 resistive layer. The multilayer Al2O3 resistive memory devices exhibit nonvolatile and bipolar resistive switching properties with high ON/OFF ratio (>10(4)), DC sweep endurance cycles (>700), statistical uniformity, and retention times (2 x 10(4) s). The role of the guide filament in the multilayer structure is identified in the non-rewritable properties of the bottom layer device, increased reset current values, and spatial temperature distribution simulation. Thus, the formation sites of the switchable filament in the top Al2O3 layer can be specified by the guide filament, resulting in remarkable improvement of reproducibility with more robust metallic percolation paths. The reliable resistive switching properties in flexible conditions is also evaluated in a bent radius of 10 mm, and the suggested flexible multilayer memory devices can provide promising strategies to be utilized in future practical storage media.