SK hynix starts mass production of 3D NAND memory with 238 layers

South Korean memory maker SK Hynix has started mass production of its 238-layer TLC NAND memory. According to the manufacturer, the memory chips are faster and more economical than its previous nand chips.

The new SK hynix memory chips achieve data transfer rates of 2.4Gbit/s per chip, which represents an increase of 50 percent compared to the previous generation of TLC NAND with 176 layers. Actual read and write speeds, in turn, increased by 20 percent. In addition, power consumption when reading data fell by 21 percent. According to the manufacturer, the new chips will be used in smartphones, PCIe 5.0 SSDs and SSDs for servers.

SK hynix demonstrated its 238-layer memory chips last year, but had not yet started mass production. By increasing the number of layers, memory makers can get more chips from a wafer. This should, among other things, lead to lower production costs. SK hynix claims its production efficiency will increase by 34 percent by switching to 238-layer memory. The South Korean memory maker starts producing 512Gbit chips, which equates to 64GB. Later this year, the manufacturer wants to double that density to 1Tbit or 128GB per chip.

SK Hynix calls its new chips ‘4D-Nand’, although in practice it is still a variant of 3D-TLC. 4D-Nand is a marketing term that the manufacturer has been using since 2018 for memory with a chargetrap flash design and a peri-under-cell layout. With CTF, charges are stored in an insulator for less interference; Traditionally this is done in a conductor. In PUC, certain circuits are placed underneath the memory cell for higher production efficiency and density. Normally these circuits are located next to the cell.

Source: SK hynix