SK Hynix Becomes First Company to Take NAND Flash Beyond 300 Layers

Memory manufacturer SK Hynix has become the first company in the world to surpass 300 layers of NAND flash, marking an important milestone in developing high-density flash storage. The company demonstrated its newest technology at the Flash Memory Summit this week in Santa Clara, Calif. by showing off a 321-layer 1Tb TLC 4D module. Don't get too excited, though; it's not coming to the market until 2025.

SK Hynix noted that transitioning to a 1Tb 321-layer die will be a massive leap from its earlier 512Gb 238-layer design. It said the advancement in density would afford an increase in "productivity" of 59%, allowing it to secure more NAND capacity from a single wafer. And since this is happening in 2023, there has to be a tie-in to ChatGPT and generative AI, with the company noting AI has caused a surge in demand for faster memory products.

SK Hynix has successfully created a 128GB module using 321-layers, but it isn't offering many details about it just yet. Credit: SK Hynix

Though the announcement represents a breakthrough for NAND technology, the company's demonstration was very light on details. For example, as Tom's Hardware notes, it didn't discuss what kind of capacities we can expect for individual SSD products or what type of interface it might utilize. However, that's likely because the technology is still two years away from entering mass production, as the company noted.

SK Hynix also didn't provide any details on its design, though it's anticipated it'll use the same peri under cell (PUC) design for its existing "4D" NAND flash products. Its competitors call this design CMOS under Array (CuA), as it features NAND logic beneath the cells to reduce their size.

A month ago, SK Hynix announced it had entered volume production for 238-layer NAND after first discussing it in late 2022. This was a significant step forward from its previous 176-layer design, with 321-layers being the next logical step. The company claimed its 238-layer NAND offers 50% faster transfer speeds than 176 layers but did not reveal the number for 321-layers. However, it will pave the way to higher-capacity SSDs at more affordable prices than we have now, so using our crystal ball, we can envision an "affordable" 8TB PCIe Gen 5 SSD when it finally arrives in 2025. Bookmark this article, and we'll see if we were right in a few years.