NAND Flash Updates: TLC for Everyone
According to a report released by DRAMeXchange in March, three-bit-per-cell NAND will account for 50% of flash production in Q4 2015. Samsung has been shipping SSD-grade TLC flash since 2012. This technology either increases the density per die or reduces the die size. Either way, density per wafer (the fixed cost) goes up. Samsung has a large lead in flash technology, but the other fab players are reading TLC now.
At Computex 2015, Micron announced its 16nm B95 TLC flash. Third-party sources tell us the company is having issues with this product, with less than 60% of its cells usable. Retail drives ship with 97% or higher usable cells. On the surface, that sounds alarming. But all new flash goes through growing pains as the process is optimized. What the number really tells us is that Micron's 16nm TLC flash is still just far enough out that we don't need to consider it as an option for retail SSDs in 2015.
We've seen Toshiba's TLC flash at trade shows for several years now, and drives based on its A19 TLC (19nm) are coming soon. SanDisk already has an offering with the NAND, though the company uses its half of Flash Forward production for in-house products. Toshiba sells third parties flash after using what it needs. So, its 19nm TLC flash will likely fuel the next round of price reductions expected in November.
Moving beyond A19, Flash Forward is aggressively developing 15nm TLC, which maintains 128Gb density but increases the number of die you get per wafer. We were told that Toshiba's A19 MLC costs around 30% more than Micron's 16nm MLC. Toshiba's 15nm TLC should cost roughly 20% less than Micron's B95 (16nm TLC).
We also managed to track down some information about next-generation 3D NAND at Computex. Each company has a flashy name like Samsung's V-NAND and Toshiba/SandDisk's BiCS. For the sake of simplicity, we're calling it all 3D NAND.
IMFT will have a few different versions in 3D. L04/L05 are both MLC and B05 is TLC. In late 2016, a special version should take shape. B0KB is 3D TLC in 384Gb density (48GB). In just three die, IMFT will have 144GB that companies can over-provision down to 128GB. If everything turns out as planned, IMFT may have a solid advantage going into the holiday shopping season. Sadly, we're not talking about the one coming in just a few months, but rather in 2016.