Stefan Mileschin

SK Hynix announced this week that they have started sampling products based on their 128-layer 3D NAND flash memory, which will soon start showing up in end-user devices. A year ago, they launched their 96-layer 5th generation 3D NAND, but low prices prompted them to cut output and their 4th generation 72L 3D NAND is still their main flash product. SK Hynix announced back in June that their 128L 3D NAND had moved from development to mass production, and now it has been incorporated into SSDs and UFS modules that are sampling to major customers.

The 96L generation represented a major technological advance for SK Hynix, with a switch to a denser "peripheral under cell" structure and a big jump in per-die IO speeds. The peripheral under cell structure is a significant enough change that SK Hynix used it as justification for branding their flash as "4D NAND", but Intel and Micron have been doing pretty much the same thing since their first generation of 3D NAND. The 128L generation from SK Hynix promises a further speed increment from 1.2GT/s to 1.4GT/s (though this may not be achieved in the first round of products due to lagging controller support), and debuts with an industry-leading 1Tb (128GB) capacity TLC die. In the near term, SK Hynix plans to introduce the new generation of 3D NAND into market segments with the highest margins, while their more mature 72 and 96-layer processes stick around for the more cost-sensitive products.

https://www.anandtech.com/show/15136...r-3d-nand-ssds