3D NAND flash is a type of flash memory in which the memory cells are stacked vertically in multiple layers.
Flash manufacturers developed 3D NAND to address challenges they encountered in scaling 2D/planar NAND technology to achieve higher densities at a lower cost per bit. Planar NAND flash technology uses a single layer of memory cells. As NAND manufacturers worked to shrink the memory cells, cell-to-cell interference caused a reduction in the reliability of planar NAND flash products.
3D NAND flash is suitable for the same types of business and consumer applications for which planar NAND is in use. Solid-state drives equipped with NAND flash can boost application performance and lower latency in comparison to traditional storage media such as hard disk drives and tape.
3D NAND vs. planar NAND: Pros and cons
3D NAND flash offers the potential for higher capacity in a smaller physical space than 2D NAND. In comparison to planar NAND, 3D NAND can lower the cost per gigabyte, improve electrical use to reduce power consumption, boost reliability, and provide higher data write performance.
One disadvantage of 3D NAND vs. planar NAND is the higher manufacturing cost, at least at the outset. The production of 3D NAND flash can take place in the same factory as planar NAND, but the layering process adds steps to the 3D NAND manufacturing process. Manufacturers often need to update, expand and/or add factories, also known as semiconductor fabs, to accommodate 3D NAND production.
Samsung was the first manufacturer to mass-produce 3D NAND flash, under the name Vertical NAND (V-NAND), in 2013. Other 3D NAND manufacturers include Intel and Micron Technology, through a joint partnership; SK Hynix; and Toshiba, which partners with Western Digital's SanDisk.
Although manufacturers take different approaches to build 3D NAND flash technology, the program/erase process to write data to a 3D NAND cell and a planar NAND cell is essentially the same.
3D NAND types
The main types of NAND flash technology are:
- Single-level cell (SLC): Stores 1 bit per cell, offers the highest endurance.
- Multi-level cell (MLC): Stores multiple bits per cell, although the term MLC typically equates to 2 bits per cell; provides lower endurance than SLC.
- Triple-level cell (TLC): Stores 3 bits per cell, offers lower endurance than SLC and MLC.
3D NAND generally uses MLC NAND flash or TLC NAND flash. Manufacturers have improved the endurance and reliability of MLC and TLC flash drives through error correction code algorithms, wear leveling and other mechanisms.