3D NAND: Can it Bridge the Endurance Gap?

Keeping close watch on durability and data protection as 3D NAND enters the Industrial IoT and M2M markets.

There’s presently a buzz surrounding 3D NAND and its growing acceptance in the industrial-embedded systems serving the Industrial IIoT (IIoT) and machine-to-machine (M2M) markets. That buzz isn’t just because of 3D NAND’s potential to dramatically boost capacities and reduce the space and power needed for solid-state storage, but also because it represents a major breakthrough in storage technology. This expansion of NAND technology into 3D production pushes flash capacities to levels that were impractical just a short time ago.

Figure 1: Flash capacities are on the rise.

An Entirely New Dimension
It’s no surprise, then, that 3D NAND was a prominent topic at the recent Flash Memory Summit. One flash maker there showcased a 96-layer chip—expected to ship in 2018—with a whopping 768Gb on a single chip. Another maker is expected to have a 1Tbit chip next year also. Mainstream bit capacity is now three bits per cell, or Triple Level Cell (TLC), and on its way is Quad Level Cell (QLC) at four bits per cell. But the real story here is that the flash makers are adding an entirely new dimension, literally, to flash storage.

Market analysts such as Objective Analysis project significant growth in the 3D NAND space in the coming years:

“Objective Analysis expects for NAND flash gigabyte consumption to grow 45 percent annually over the long-term. This means that six times as many flash exabytes will ship in 2021 as did in 2016. Revenues won’t rise at that rate, though, since prices are ripe for a collapse, which we expect to occur once 3D NAND begins to be manufactured efficiently. This will be triggered by a breakthrough whose timing can’t be pinpointed. Our current outlook is for that breakthrough to occur in mid-2018.”

With these new 3D approaches to manufacturing, there is a tradeoff—and we should expect some sort of compromise between endurance and capacity. After all, packing three bits per cell into the chips and then manufacturing them into a layered solution is a new concept that’s still in the improvement stage, and therefore subject to initial endurance challenges.

That’s where Virtium is focusing its efforts. While lower-endurance chips may be fine for consumer applications and possibly select enterprise storage environments, the industrial market can’t compromise endurance for the sake of capacity. The myriad customer designs using Virtium industrial-grade products over the past 20+ years all have one thing in common: They absolutely require durability and data protection, even in the most extreme environments.

Figure 2: Like the human brain, 3D NAND’s multi-dimensional form enables near-limitless capabilities.

Durability of SSDs and protection of data aren’t arbitrary requirements or the demands of overly cautious designers, either; the data collected by embedded, IIoT, and M2M applications and stored in flash devices, 3D NAND or otherwise, is oftentimes business-critical. Information is currency, and the importance of that currency highlights the distinctions between off-the-shelf SSDs and those designed and built for those business-critical applications.

More at Stake
Consumer-grade SSDs do not require the endurance and reliability of industrial-grade SSDs. Consumer-grade SSDs are sufficient for desktop and laptop computers, but industrial applications require a more robust product—with a longer product life cycle and tolerant of a wider temperature range.

Additionally, consumer-grade SSDs don’t fit the embedded and IIoT mold because they may exceed power requirements and are only available in form factors of consumer applications. On the enterprise side, the higher capacities and high IOPS, which add to higher power requirements and cost overruns, simply aren’t needed for industrial applications.

Because IIoT endpoints are usually found in harsh and/or remote environments, the SSDs used here must be able to support extreme temperatures, vibration, and shock. They also must be built with a “set it and forget it” purpose and last longer than your typical SSD. Because the applications and the critical data they collect and store simply cannot be compromised, SSDs can also be subject to monitoring and predictive analysis. So, there’s far more at stake in embedded-system, IIoT, and M2M data collection and storage applications. And those stakes serve as guiding factors as flash makers develop devices with significantly higher capacity, as we’re witnessing in 3D NAND, without compromising the durability of SSDs or protection of their data.

We at Virtium are watching closely how 3D NAND evolves—it may at some point bridge the endurance gap and be suitable for demanding IIoT applications. In the meantime, the flash chips Virtium does use for our industrial-embedded SSDs, coupled with the drive-manufacturing processes we employ, ensure customers the drives will withstand harsh environments and the data they contain will be well protected.

Scott Lawrence is Director of Business and Technology Development, Virtium Solid State Storage and Memory.