China’s CXMT unveils ‘key progress’ on chip structure pursued by Samsung, SK Hynix

China's memory chip leader, ChangXin Memory Technologies (CXMT), announced "key progress" in a novel chip structure that rivals Samsung Electronics and SK Hynix are also pursuing to increase memory density. CXMT aims to launch a new server-memory product based on this structure by the end of 2026, according to president Cao Kanyu's remarks at a Shanghai industrial event.

The foundation of this advancement is the innovative "4F square" design, where each memory cell occupies a four-square F area, with F denoting the minimum line width in a semiconductor. This structure allows for higher storage density by cramming more cells onto a single chip. At present, standard commercial dynamic random-access memory (DRAM) employs a 6F square-cell structure.

Major DRAM producers worldwide are investing in this technology. In 2025, SK Hynix unveiled its 4F square roadmap, while South Korean media reported that Samsung planned to mass-produce sub-10-nanometre DRAM based on the new design by 2028. CXMT's core 4F square design relies on its proprietary Vertical Surrounding Gate (VSG) transistor, which employs a vertical gate architecture to mitigate current leakage and significantly reduces unit area, thereby boosting storage density.

Transitioning from the widely used 6F square structure to the 4F square represents a fundamental shift from horizontal to vertical transistor channels. As existing manufacturing flows cannot be adapted to the new structure, CXMT had to redesign pivotal processes to optimize the performance-to-power ratio. Based in Hefei, the capital of China's Anhui province, the company expects to release a new generation of DDR5 RDIMM by year-end.

This enterprise-grade server memory module will incorporate the advanced technology. However, CXMT has not disclosed detailed specifications or a launch date for the server product, emphasizing the need for higher endurance, compatibility, and resistance to voltage fluctuations compared to consumer memory products. The product must also pass hundreds of compatibility tests with CPUs and motherboards from various manufacturers.

Since listing on Shanghai's Star Market in July, CXMT has taken several steps to display its technological prowess. Last month, the company announced that its fifth-generation DRAM manufacturing platform, the G5, had entered mass production, further narrowing the gap with global industry leaders. Founded in 2016, CXMT has been researching the 4F square architecture since its inception and has published over 300 related patent families, outpacing both domestic and overseas competitors.