TORONTO – Two years after entering the client segment, triple-level cell (TLC) is expected to gain further traction in the data center, but in the long term conventional NAND growth with slow as 3D takes over.
To date, TLC has been primarily used in USB drives, flash memory cards, low-cost smartphones, client solid state drives (SSDs), said Gregory Wong, principal analyst with Forward Insights, but it’s starting to see use in the iPhone 6 and he anticipates it make further incursions into high-end smartphones and enterprise data center SSDs in 2015 and 2016.
A similar forecast is shared by Gartner, which saw some adoption by select customers in the data center this year, according Joe Unsworth, research VP for semiconductors. The research firm expects 3-bits-per-cell and 3D to be the focal point of NAND technology evolution over the next year, noting that Samsung commercialized 3D NAND in 2014, but adoption will still be slow until late 2016, when all vendors will have commercialized it. Until then it will continue to be an multi-level cell (MLC) and TLC world, he said.
Source: Gartner December 2004 – Preliminary: “NAND Flash Supply and Demand World Wide”
MLC will continue to be used in smartphones, tablet and SSDs through 2016, said Wong, and likely some Android-based smartwatches as they gain popularity next year, while single-level cell (SLC) continues to be used in consumer applications such as set-top boxes, digital cameras, printers and mobile devices. However, its volume has declined as mobile devices and cameras have moved to MLC. The main growth for SLC will come from industrial and automotive applications, said Wong.
One of the reasons TLC is seeing growth and finding viability in data center applications is smarter controllers that address concerns such as endurance. Overall, Gartner sees flash management firmware and advanced controllers to be differentiators in the NAND market.
Jim Handy, principal analyst with Objective Analysis said TLC has “come out from under a rock” in that it used to be relegated to low-write application such as flash cards, USB flash drives and MP3 players, but since 2013 has been used successfully in client SSDs offered by Samsung and SanDisk. “The same architectural tricks that allow MLC to replace SLC can be used to allow TLC to replace MLC,” he said. However, TLC is priced at about 80% of the cost of MLC, so there’s not as much of a push to go from MLC to TLC, whereas MLC was 50% of the cost of SLC, offering a much better cost advantage.
Handy doesn’t expect SLC to completely vanish, but shipments will be smaller in volume and higher in costs with a small number of vendors such as Spansion and Macronix satisfying market demand.
Like Gartner, Handy sees controllers a critical differentiator as they have become smarter and more sophisticated and have allowed lower cost TLC to enter new segments, although the controllers are costing more. But controllers do have their limits, he said, as there are only so many errors they can correct. When that limit is hit, the amount of flash has to be increased and redundancy built in.
TLC will never completely unseat MLC, said Handy. “MLC is used basically everywhere. This will be the case for the next two years, if not longer.” However, 3D NAND will likely use more TLC than planar NAND has, he said, as it lends itself better to TLC.
But he too doesn’t see 3D NAND ramping up until 2016; ultimately, TLC and 3D NAND will compete as the lowest cost NAND flash option.