
▲SK Hynix 321-layer 4D NAND (Photo: SK Hynix)
Development status revealed at FMS 2023
World's first 300-layer NAND
SK Hynix has officially announced that it is the first in the industry to develop a 300-layer or higher NAND by unveiling a sample of its '321-layer 4D NAND'.
SK Hynix announced the development progress of 321-layer 1Tb (terabit) TLC (Triple Level Cell) 4D NAND flash and exhibited samples in the development stage at the 'Flash Memory Summit (FMS) 2023' that opened in Santa Clara, USA on the 8th (local time).
SK Hynix is the first company in the memory industry to disclose the specific development progress of 300-layer or higher NAND. The company also announced plans to improve the perfection of 321-layer NAND and begin mass production in the first half of 2025.
An SK Hynix official emphasized, “We are progressing smoothly with the development of 321-layer NAND based on the technological prowess we have accumulated through the current highest-layer 238-layer NAND currently in mass production,” and “By once again breaking through the stacking limit, SK Hynix will open the era of 300-layer NAND and lead the market.”
The 321-layer 1Tb TLC NAND has a 59% increase in productivity compared to the previous generation 238-layer 512Gb (gigabit). This is because cells that store data can be stacked in higher layers, enabling greater capacity in a single chip, thus increasing the overall capacity that can be produced from a single wafer.

▲SK Hynix 321-layer 4D NAND (Photo: SK Hynix)
Recently, the memory market is experiencing a rapid increase in demand for high-performance, high-capacity memory to process and store more data faster due to the growth of the generative AI market triggered by Chat GPT.
SK Hynix also introduced its next-generation NAND solution products optimized for such demands, the Enterprise SSD (eSSD) with the PCIe 5th generation (Gen5) interface and UFS 4.0, at this event.
We expect that these products will achieve industry-leading performance and sufficiently satisfy the needs of customers who emphasize high performance.
Through these products, the company announced that it has begun development of the next generation PCIe 6th generation and UFS 5.0 based on its advanced proprietary solution development technology, and expressed its will to lead the industry's technology trends.
SK Hynix Vice President Choi Jeong-dal (NAND Development) said in his keynote speech at the event, “Our company plans to solidify our NAND technology leadership by developing the 5th generation 321-layer 4D NAND product,” adding, “We will lead innovation by proactively introducing high-performance, high-capacity NAND to the market that the AI era demands.”
In the conference call for the second quarter, the memory industry, including SK Hynix, announced an additional 5-10% reduction due to slower-than-expected depletion of NAND flash inventory.As Suga leads the HBM3 market and is now leading the NAND flash technology race, attention is being paid to the future of the memory industry.