Ultra-high bit density liquid-state colloidal memory

Despite the historical growth of storage technologies, such as 3D NAND flash, hard disk drives, and tape storage, each of them is facing inherent scaling limitations. 3D NAND flash suffers from rising costs due to the complex 3D fabrication process. The growth rate of the areal bit density for hard disk drives is limited due to superparamagnetic behavior. Tape storage, though, continues to scale in areal bit density, has the disadvantage of high latency. To address these challenges, an alternative memory, “colloidal memory,” is suggested. This memory concept consists of an array of access devices and nanocapillaries immersed in a colloidal mixture of two particle types, which are encoded as “0” and “1”. Using dielectrophoresis, particles are written in the nanocapillaries, where the order of these particles represents a bit string. In this paper, we showed that the theoretical areal bit density is up to approximately 160 Gbit/mm 2 . The design criteria for two particle types, protagonistic and antagonistic particles, are established through both a conventional core-shell model and an advanced electrokinetic model. Then, the writing and reading operations are investigated to evaluate the performance characteristics. This allows us to estimate the potential application space for the colloidal memory. Ultimately, this work introduces the colloidal memory as a novel memory concept and assesses its feasibility.