China's CXMT touts denser memory cells, Samsung and SK Hynix shares slide

Chinese memory chipmaker ChangXin Memory Technologies (CXMT) says it has made key progress on a DRAM cell design known as 4F². President Cao Kanyu told an industry conference in Shanghai over the weekend that the company plans to launch DDR5 server modules (RDIMMs) based on the technology before the end of 2026. CXMT did not disclose detailed specifications or a specific launch date.

Mainstream DRAM today uses a 6F² layout, in which each memory cell of one transistor and one capacitor occupies six times the square of the smallest feature size. A 4F² cell needs only four, achieved by arranging the components more vertically. CXMT uses an in-house vertical surrounding-gate transistor. Trade reports say the approach can raise cell density per chip by 30% to 50%. Samsung is reportedly not targeting mass production with the architecture until 2028.

Investors in Seoul sold on Monday: Samsung Electronics and SK Hynix fell as much as about 4% in intraday trading, with Samsung dropping to 252,500 won. CXMT's shares, listed in Shanghai since July, lost about 3%. None of the three major memory makers, Samsung, SK Hynix and Micron, has yet brought 4F² memory to market at scale.