SK hynix has just unveiled the industry's highest-layered NAND technology with 321-layer design in up to 1 Tb TLC packages.
SK hynix Unveils 321-Layer TLC NAND, 1 Tb Flash Tech To Hit Mass Production In 1H 2025
Press Release: SK hynix Inc. showcased today the sample of the 321-layer 4D NAND, making public the progress on its development of the industry’s first NAND with more than 300 layers.
The company gave a presentation on the progress of the development of its 321-layer 1Tb TLC* 4D NAND Flash and displayed the samples at the Flash Memory Summit (FMS) 2023** taking place Aug. 8-10 in Santa Clara.
SK hynix is the first in the industry to unveil the progress on the development of a NAND with more than 300 layers in detail. The company plans to raise the level of completion of the 321-layer product and start mass production in the first half of 2025.
The company said its technological competitiveness accumulated from the success of the world’s highest 238-layer NAND, already in mass production, paved the way for smooth progress for the development of the 321-layer product. “With another breakthrough to address stacking limitations, SK hynix will open the era of NAND with more than 300 layers and lead the market.”
The 321-layer 1Tb TLC NAND comes with a 59% improvement in productivity, compared with the earlier generation of 238-layer 512Gb, thanks to the technology development that enabled the stacking of more cells and larger storage capacity on a single chip, meaning the total capacity that can be produced on a single wafer increased.

Since the introduction of ChatGPT which accelerated the growth of the generative AI market, demand for high-performance and high-capacity memory products that can process more data at a faster pace is growing rapidly.
Accordingly, at the FMS, SK hynix also introduced next-generation NAND solutions optimized for such AI demand, including the enterprise SSD adopting the PCIe Gen5 interface and UFS 4.0. The company expects these products to achieve industry-leading performance to fully meet the needs of the customers with a focus on high performance.
SK hynix also announced that it has started the development of the next-generation PCIe Gen6 and UFS 5.0 with the improved technology for solution development that it acquired through these products and expressed its commitment to leading the industry trend.









