Samsung Electronics Co. Ltd. confirmed today it has started making available to PC manufacturers its second generation of three-dimensional flash memory, known as Vertical NAND, which improves write endurance and consumes less power than conventional flash.
The company's new Vertical NAND (V-NAND) uses 32 vertically stacked flash cell layers rather than 24 layers used in the first generation of V-NAND, which was introduced last year. Samsung said solid-state drives (SSDs) based on the new 3-D V-NAND will have approximately twice the endurance for writing data and will consume 20% less power compared to planar multi-level cell (MLC) SSDs.
Samsung introduced its 3-D V-NAND technology for data center use last year. The company claimed the customer base for its first-generation V-NAND SSDs included enterprise IT customers and large-scale data centers.
But Samsung is making the second-generation V-NAND SSDs available only to the PC market so far, according to a company spokesman. The company did not provide a date when it expects to make available the second-generation V-NAND SSDs to enterprise system manufacturers.
A Samsung spokesman said via email, "We are open to providing the second generation V-NAND SSDs to enterprise server and storage vendors and will try our best to support such customer needs as they occur."
Greg Wong, founder and principal analyst at Forward Insights in North York, Ontario, said a handful of customers have the first-generation V-NAND SSDs, and the drives are not available through the channel. He said samples shipped when Samsung made its 3-D V-NAND announcement last August.
Samsung makes V-NAND chips and SSDs but it does not currently offer the V-NAND chips for sale to other SSD manufacturers. The company said it started mass production of both the chips and SSDs in May and plans to increase production as customer demand grows.
Plans call for premium SSDs based on the second-generation V-NAND to be available in capacities of 128 GB, 256 GB, 512 GB and 1 TB. Samsung also expects later this year to introduce additional premium 3-D NAND-based SSDs with densities in excess of 1 TB and greater reliability, according to a company spokesperson.
"This is an important breakthrough for NAND technology, scaling to enable cost reductions with as minimal compromise to performance and reliability as possible," said Joseph Unsworth, a research vice president for NAND flash and SSD technology at Gartner Inc., via email. "Corporate customers will benefit from lower prices should this technology be able to scale successfully and Samsung stands behind the technology with its warranty terms. Otherwise, there is no real breakthrough for enterprise users."
Samsung said it can achieve greater production efficiency with 32-layer 3-D V-NAND because it can use the same equipment that it used to produce the 24-layer V-NAND.
When Samsung announced its first-generation 3-D NAND flash last year, the company said the V-NAND was the result of years of employee effort to pursue new approaches to overcome limitations in the design of memory semiconductor technology.
Samsung said that, for decades, conventional NAND flash memory has been based on planar structures that make use of floating gates. But, as the manufacturing process technology has advanced to the 10-nanometer class and beyond, concerns over scaling limits have surfaced because of the cell-to-cell interference that causes a tradeoff in reliability, Samsung noted.
The company said its new 3-D V-NAND addresses the technical challenges through innovations in circuits, structure and the manufacturing process via the vertical stacking of planar cell layers. Instead of using a floating gate to prevent interference between cells, Samsung uses 3-D Charge Trap Flash (CTF) technology to temporarily place an electric charge in a holding chamber of the non-conductive layer of flash, which is composed of silicon nitride. Making the CTF layer three dimensional improves reliability and speed, according to Samsung.
The trend toward 3-D NAND flash extends beyond Samsung to SanDisk and Toshiba, which refer to their technology as bit cost scalable (BiCS), Unsworth noted.
"We expect all NAND vendors to manufacture some form of 3-D NAND technology, and all of them will be sampling at some point in 2015," Unsworth said. "However, we do not expect 3-D NAND to gain widespread adoption until its cost structure is more competitive (through scale and more layers beyond 32 layers), there are multiple sources, and customers (such as PC and storage OEMs) quantify it and validate the technology."
Tom Coughlin, president of Coughlin Associates, a data storage consultancy in Atascadero, California, said he hasn't seen much in the way of shipping products based on 3-D NAND flash technology. But, he said he expects that to change based on recent announcements from Samsung, SanDisk and Toshiba about new 3-D NAND fabs to make the chips.
"It's pretty clear that they all see that as the not-too-distant future," Coughlin said. He predicted the volume of 3-D NAND products will ramp up in 2016 or 2017.