Multi-level cell

Overall, the memories are named as follows: Notice that this nomenclature can be misleading, since an "n-level cell" in fact uses 2n levels of charge to store n bits (see below).

Typically, as the "level" count increases, performance (speed and reliability) and consumer cost decrease; however, this correlation can vary between manufacturers.

New technologies, such as multi-level cells and 3D Flash, and increased production volumes will continue to bring prices down.

Due to higher transfer speeds and expected longer life, SLC flash technology is used in high-performance memory cards.

[5] The primary benefit of MLC flash memory is its lower cost per unit of storage due to the higher data density, and memory-reading software can compensate for a larger bit error rate.

TLC and QLC devices may need to read the same data up to 4 and 8 times respectively to obtain values that are correctable by ECC.

In 1997, NEC demonstrated a dynamic random-access memory (DRAM) chip with quad-level cells, holding a capacity of 4 Gbit.

[16][17][18] As of 2018,[update] nearly all commercial MLCs are planar-based (i.e. cells are built on silicon surface) and so subject to scaling limitations.

To address this potential problem, the industry is already looking at technologies that can guarantee storage density increases beyond today’s limitations.

It claims to last longer and be more reliable than normal MLCs while providing cost savings over traditional SLC drives.

Although many SSD manufacturers have produced MLC drives intended for enterprise use, only Micron sells raw NAND Flash chips under this designation.

[citation needed] Due to the exponentially increasing number of required voltage stages for higher level flash the lifetime of QLC is further reduced to a maximum of 1,000 program/erase cycles.

[30][31] In 2017, Toshiba introduced V-NAND memory chips with quad-level cells, which have a storage capacity of up to 768 Gbit.