Flash storage (like SSDs) is all the rage for PCs these days. And though the process isn’t going as fast as we might hope for, that storage is getting cheaper and denser all the time, creeping up in value towards conventional spinning disk hard drives. The biggest leap forward as of late has been 3D NAND flash, also known as vertical NAND or “V-NAND.” What does this mean for you? In layman’s terms, cheaper and faster storage and memory. In non-layman’s terms, well, let’s take a look.
Imagine a piece of flash storage as an apartment building: lots of compartmentalized areas in which people need to get in or out, spending varying amounts of time either in (a “1” state for a single bit of data, in this metaphor) or out (“0” state) of their homes. Now, the most valuable resource you have if you’re building a new apartment building is the real estate you want to build it on. Ignoring mundane obstacles like engineering and budget, your goal is to put the maximum amount of people possible in a set area of land.
A hundred years ago, the obvious answer to this problem would be to subdivide apartments as small as possible on the inside of your building, maximizing the amount of people you can fit into a single story. Now with the advent of steel buildings and fast, safe elevators, we can build up to the limit of our new materials. We can add in as many stories to the building as we can physically manage, allowing ten, twenty, or fifty times as many people to live on the same amount of land that was previously so limited.
So it is with 2D and 3D NAND. Because we’re talking about bits and not people, companies have already worked hard to cram as much data as possible into the X and Y planes of semiconductor components, and now they’re building vertically up from the circuit board. There are still physical limitations, of course—a RAM DIMM that’s three inches thick isn’t much use, even if you can fit ten terabytes of data in there. But new techniques in chip and memory fabrication allow microscopic layering of the NAND architecture, very much like a high-rise apartment building. These layering and fabrication techniques make vertical memory that’s denser, faster, and more efficient inch-for-inch versus older hardware.
With this new layered style of memory fabrication, more and more data can be crammed into the same amount of physical space. Not only that, but miniaturization techniques that are still being applied to more conventional RAM and flash storage also “stack,” granting more benefits the more layers you can put onto a memory module. And since the physical space for all of this stuff is getting tinier and tinier, latency, power usage, and read and write speed are all decreasing at a faster pace, too. Advancements like channel holes allow even faster data transfer up and down the layers of semiconductors—sort of like tiny elevators in our original apartment building metaphor.
The vertical NAND technique is benefiting all sectors of the market for flash storage, but predictably, industrial interests are seeing the best returns. Incredibly complex fabrication processes allow for super-dense blocks of RAM and storage that are too expensive for standard consumer electronics, but still allow a return on investment for data centers and high-power workstations.
Even so, 3D NAND has already made its way to the consumer market, and the benefits for pure data retention in solid state drives are dramatic. That being said, it’s not quite as revolutionary as it might appear to be at first: thanks to an ever-growing demand for flash memory among electronics manufacturers, corporate data customers, and regular consumers like you and me, there’s currently a worldwide shortage of flash memory at all levels. So costs are still fairly high.
Between increased demand from all markets and the cost of constantly improving and upgrading fabrication centers to make more advanced components, the price and availability of both standard PC RAM and SSD storage seems to be in a multi-year rut. Though newer 3D NAND chips are available, and they’re faster and more efficient, we’re not seeing the drop in price and rapid boost in capacity that such big steps would suggest on their own. The dream of stuffing your gaming PC with dozens of terabytes of super-fast flash memory and storage on the cheap is still a way away.
But the trickle-down effect of new techniques and technology is more or less inevitable. A boom in flash memory and storage is coming, as more and more suppliers switch over and improve their 3D semiconductor fabrication capabilities. It might just take a few more years—and a few more dollars—than we were hoping.