IM Flash Technologies, Intel's joint venture with Micron, is responsible for the flash memory in an awful lot of modern SSDs. Most recently, the partnership's 20-nm NAND has appeared in the Intel 335 Series and the Crucial M500. What's next? IMFT co-CEO Keyvan Esfarjani told the IMEC Technology Forum that 15-nm and 10-nm NAND are both possible with current two-dimensional structures. However, according to EE Times, Esfarjani said that IMFT is counting on 3D NAND structures to carry the firm beyond 10 nm.
Intel already has a 22-nm chip fabrication process that uses a "3D" gate structure, but that's not what Esfarjani is talking about. 3D NAND refers to flash memory that stacks multiple cell layers on top of each other. EE Times notes that Toshiba has been hyping 3D NAND tech for years, and that it's due to start sampling a 16-layer device this year. Esfarjani told the conference that 32-64 layers are needed to make 3D flash cost-effective.
3D NAND is probably a few years away, so what's IMFT working on for the 2D stuff? Nitride film and nanodots, according to Esfarjani. It's unclear whether either will be necessary to shrink cells for 15-nm production, but the challenge appears to be making the cells last with that smaller geometry. As NAND cells shrink, their write/erase endurance tends to degrade.
Finer fabrication techniques have been largely responsible for falling SSD prices, and it looks like 2D technology still has a few generations left. It will be interesting to see whether the downward trajectory continues as we move to 15- and 10-nm NAND. The demand for flash is likely to keep growing, and we've already seen SSD prices rebound a little from the deep discounts that were so common last year.