First Demonstration of RRAM Patterned by Block Copolymer Self-Assembly

We report the first metal oxide RRAM device fabricated using diblock copolymer self-assembly lithography patterning. This patterning technique enables us to successfully scale down the memory device to less than 12 nm. The fabricated bi-layer TiOx/HfOx devices show excellent performance: low forming voltages (similar to 2.5 V) and low switching voltages (<1.5 V); good cycle-to-cycle and device-to-device uniformities, reasonable endurance (>1E7 cycles) and retention property (>4E4 s @125 degrees C). Furthermore, self-assembly patterned single-layer HfOx-based RRAM devices is demonstrated with faster switching speed (similar to 50 ns), multi-level storage (2 bits/cell), longer endurance (>1E9 cycles), half-selected read immunity (similar to 1E9 cycles), good retention (>1E5s @125 degrees C).