3Dnand

3D NAND is a type of NAND flash memory in which memory cells are built in vertical stacks, enabling greater storage density than traditional planar (2D) NAND. By layering many cells, 3D NAND achieves higher capacity per silicon area and lower cost per gigabyte, while also reducing device footprint and improving endurance relative to equivalent planar devices.

Architecture and cell types: Cells are organized in vertical columns formed by multiple stacked layers connected by a shared channel. The stack can use different cell designs, including floating-gate and charge-trap memory, and supports multiple bit-per-cell configurations such as SLC, MLC, TLC, and QLC. Early products used through-silicon stacking, and newer approaches include monolithic 3D NAND, where additional layers are grown directly on the same substrate to achieve higher densities. The technology aims to minimize interference between layers and cells as density increases.

Performance and reliability: 3D NAND generally offers higher density and longer device lifetimes per unit area than planar NAND, with improved resistance to some read and program disturbances due to its stacked architecture. However, higher-bit-per-cell variants (TLC and QLC) have lower write endurance and data-retention characteristics, necessitating stronger error correction and wear leveling. Read and write speeds vary by generation and controller, but 3D NAND typically provides competitive performance for consumer and enterprise storage.

History and usage: Major manufacturers include Samsung (V-NAND), Toshiba/SanDisk (BiCS), SK hynix, Micron, Western Digital, and Kioxia. 3D NAND is now widely used in consumer and enterprise SSDs, USB flash drives, and memory cards, forming the basis of most modern solid-state storage solutions.