High-Density 3-D NAND Cell Array Design With Hybrid Bonding

In this study, we propose a novel cell array structure suitable for hybrid bonding technology, which is considered one of the promising future technologies in 3-D NAND architecture. By dividing the common source line (CSL) in the cell array into multiple source lines (SLs), this structure allows for the removal of the dummy cell area that hinders the increase in bit density in a conventional cell array. Through the removal of dummy cells, the bit densities in nine-and 24-cell structures can be increased by 8% and 15%, respectively. As the proposed structure is not compatible with the conventional method in the program operation, we also propose a new programming method suitable for this structure and verify it through technology computer-aided design (TCAD) simulations. The proposed method can achieve string selection and inhibition by utilizing the asymmetric gate-induced drain leakage (GIDL) phenomenon at both ends of the string and is expected to improve V-PASS disturbance.