Micron has decided not to adopt its next-generation 4F2 DRAM structure, which it has researched for about 20 years, in actual products.

On Oct. 23, local time, online outlet Gigazine reported that Micron decided to focus on advancing its existing 6F2-based DRAM, citing greater manufacturing process complexity, rising costs and limits to further scaling.

The decision emerged when Scott DeBoer (스콧 데보어), Micron’s president and chief technology and product officer, disclosed the company’s DRAM development plans at a technology briefing held on Oct. 21. The 4F2 DRAM has drawn attention as a next-generation high-density memory technology because it can reduce memory cell area compared with 6F2. In theory, it cuts cell area by about 33 percent on the same process basis and allows more cells to be placed in the same area.

Micron, however, concluded after long-term research and prototype production that mass-production feasibility did not match expectations. DeBoer said 4F2 DRAM was a technology Micron devised and the company has continually evaluated. He added that it has deferred applying it to products because manufacturing becomes more complex and costs rise.

The key issue is density. Micron judges that while 4F2 focuses on reducing transistor area, overall DRAM density is more heavily influenced by the size of capacitors that store data and the spacing of their placement. DeBoer said it is a misunderstanding to think the difference between 4F2 and 6F2 directly translates into improved storage density. He said circuits must be designed to match capacitor spacing, and process complexity and costs must be optimised together.

Sustained scaling was also raised as a problem. Micron said it believed 4F2 DRAM could be manufactured at process levels from several generations ago, but physical constraints grow as structures shrink further at today’s most advanced technology. DeBoer said these limits make 4F2 difficult to use as a long-term solution.

Micron has therefore chosen a strategy of continuing to scale 6F2-based DRAM instead of switching to 4F2. It plans to begin mass production of its 1δ generation in the second half of 2027, aiming to raise storage density by the mid-20 percent range versus the previous generation. In later generations, it plans to continue planar scaling by using wafer bonding, high-numerical-aperture EUV lithography and new materials.

Over the long term, 3D DRAM was presented as an alternative. 3D DRAM stacks memory cells vertically to reduce reliance on planar scaling. DeBoer said a shift to 3D DRAM will ultimately be needed given the fundamental limits of 4F2. He did not disclose a commercialisation timeline. Micron plans to decide when to introduce it by weighing manufacturing costs, process complexity and performance comprehensively.

Against this backdrop, the competitive landscape for next-generation DRAM technology is also drawing attention. Samsung Electronics and SK Hynix are still reported to include 4F2 DRAM in their future technology development plans. Micron did not deny the technical feasibility of 4F2, but it has effectively prioritised improving existing structures and shifting to 3D DRAM in business terms.