SK Hynix presents 3D NAND with 238 layers for faster and cheaper SSDs
Memory manufacturer SK hynix has developed 3D nand memory with 238 layers, the highest number of layers in the industry. These chips will be the first to be used in desktop SSDs. Mass production will start in the first half of next year.
The 238-layer nand memory is tlc nand and should succeed the current 176-layer nand generation, writes SK hynix. The South Korean manufacturer introduces the new memory type in the form of 512Gbit chips, each of which has a capacity of 64GB. In time, that density must be doubled to 1Tbit or 128GB per chip.
According to the manufacturer, the speed is 50 percent higher than its previous generation nandflash, with transfer speeds of 2.4 Gbit/s per chip. Power consumption when performing read commands has also been reduced by 21 percent. With the step to 238 layers, the die size for TLC nand chips also decreases, which means that SK hynix can extract more memory from a wafer. This should, among other things, lead to lower production costs.
The manufacturer calls this memory “4d-nand,” a marketing name the company has been using since 2018 to designate memory with a charge trap flash design, or ctf design, and a peri-under-cell layout. With ctf, those charges are stored in an insulator. Traditionally, nand chips have been produced with floating gate designs, where electrical charges are stored in a conductor. The ctf approach should avoid interference between memory cells for better performance. With periphery under cell, peripheral circuits are placed directly under the memory cell. Normally those circuits are located next to the memory cell. According to SK hynix, this improves production efficiency and density.
SK hynix will begin mass production of its 238-layer nand memory in the first half of 2023. The chips will initially be used in client SSDs for PCs and laptops. Server SSDs and storage chips for smartphones will follow later. The 1Tbit chips with 238 layers will also follow in 2023, but a more concrete release period is not given.
Source: SK hynix