Metal Nanodot Memory by Self-Assembled Block Copolymer Lift-Off

As information technology demands for larger capability in data storage continue, ultrahigh bit density memory devices have been extensively investigated. To produce an ultrahigh bit density memory device, multilevel cell operations that require several states in one cell have been proposed as one solution, which can also alleviate the scaling issues in the current state-of-the-art complementary metal oxide semiconductor technology. Here, we report the first demonstration of metal nanodot memory using a self-assembled block copolymer lift-off. This metal nanodot memory with simple low temperature processes produced an ultrawide memory window of 15 V at the +/-18 V voltage sweep. Such a large window can be adopted for multilevel cell operations. Scanning electron microscopy and transmission electron microscopy studies showed a periodic metal nanodot array with uniform distribution defined by the block copolymer pattern. Consequently, this metal nanodot memory has high potential to reduce the variability issues that metal nanocrystal memories previously had and multilevel cells with ultrawide memory windows can be fabricated with high reliability and manufacturability.