Understanding Metal‐Induced Lateral Crystallization in 3D NAND Flash Memory Through Mechanistic Growth Analysis

ABSTRACT Metal‐induced lateral crystallization (MILC) behaves differently in vertical and confined geometries compared with conventional planar layouts. In this work, we use MILC whisker‐based Monte Carlo simulations supported by experimental validation to analyze the distinct growth behavior of MILC in vertical and narrow structures. First, vertical structures exhibit reduced Ni contact area, fewer NiSi 2 whisker seeds, and a limited Ni supply, which collectively slow growth and shorten the maximum propagation length. Second, in narrow structures, constrained whisker trajectories increase the probability of entrapment, amplifying variability and restricting propagation. Finally, when these constraints coexist in vertical 3D NAND flash memory channels, experiments reveal a strong tendency toward premature termination and pronounced propagation scatter. To overcome these limitations, we propose and validate a plug‐type MILC structure that expands the Ni contact area in vertical 3D NAND flash memory, thereby increasing the number of seeds, preventing premature termination, and significantly enhancing both growth length and reliability. This study provides direct insight into how structural constraints in 3D NAND architectures influence MILC growth and offers practical guidelines for achieving optimized crystallization in vertical channel memory devices.