Shares of South Korean memory chip giants Samsung Electronics and SK Hynix fell sharply on Tuesday following a weekend claim by Chinese manufacturer CXMT Corp about a breakthrough in memory chip technology. SK Hynix shares dropped 10 percent, while Samsung’s declined 7.4 percent, contributing to a broad decline in South Korea’s Kospi index.
At a conference in Shanghai over the weekend, CXMT President Cao Kanyang announced that the company plans to launch a data center server memory chip with a 4F² design by the end of this year. A company spokesperson later confirmed the statement, although no additional technical details have been provided and the announcement has not yet been independently verified.
The claim centers around CXMT’s development of a 4F² DDR5 server memory chip. The term “4F²” refers to the area consumed by each memory cell in relation to the minimum feature size, or “F,” of the chip’s manufacturing process. Current industry standards operate at 6F², so the 4F² design would allow significantly higher density — around 30 to 50 percent more memory capacity on the same chip area. This improvement could translate into more cost-effective memory chips for servers.
However, achieving a 4F² footprint requires a complex design involving vertical transistors with channels running perpendicular to the chip surface, encased by closely wrapped gates. Such structures have faced manufacturing challenges and leakage issues, complicating mass production.
South Korean rivals SK Hynix and Samsung Electronics have been pursuing similar vertical-channel DRAM designs for several years. SK Hynix holds a patent covering 4F² vertical-channel DRAM cells but acknowledges the difficulties in manufacturing at scale. Samsung publicly initiated a 3D DRAM project in 2021 and established a dedicated team in May 2023 aimed at developing mass production of 4F² cells. Industry reports in mid-2025 indicated that both firms hoped to validate working 4F² prototypes by the end of the year, though large-scale commercialization is not expected until around 2028.
The timing of CXMT’s claim has unsettled investors, as it suggests the Chinese company could leapfrog established market leaders despite restrictions imposed by U.S. sanctions, which bar CXMT access to advanced manufacturing equipment such as ASML’s top-tier lithography machines. The announcement also impacted international markets, with Micron Technology’s shares closing 4 percent lower in New York ahead of Seoul’s trading session.
Beyond immediate stock market effects, CXMT’s progress underscores shifting dynamics in the global dynamic random-access memory (DRAM) market. Counterpoint Research data indicates CXMT’s market share expanded to 10 percent in the second quarter of 2026, up from 4 percent a year earlier. The company is also reportedly developing LPDDR6 smartphone memory modules on a schedule comparable to South Korean manufacturers. CXMT’s recent initial public offering briefly made it China’s most valuable technology company.
If CXMT is able to commercialize its 4F² server DRAM chip by December as claimed, it would place the company approximately two years ahead of major competitors such as Samsung and SK Hynix, potentially reshaping competition in the memory chip sector. However, industry observers remain cautious as the claim has yet to be independently substantiated and technical hurdles remain significant.