Kioxia and Western Digital formally introduced their 8th Generation BiCS 3D NAND memory with 218 active layers. The new storage device offers a 1Tb capacity in 3D TLC mode and features 3200 MT/s data transfer speed, a combination that will enable SSD makers to build high-performance, high-capacity drives. To enable such an extreme interface speed, the companies adopted an architecture akin to YMTC's Xtacking.

The 218-layer BiCS 3D NAND device jointly developed by Kioxia and Western Digital supports triple-level cell (TLC) and quad-level cell (QLC) configurations to maximize storage density and expand addressable applications. The companies said that the new device embraces their new 'lateral shrink technology to increase bit density by over 50' without elaborating. Considering that the flash memory IC increased the number of active layers by 34%, the claim about a 50% bit density increase indicates that developers also shrank lateral sizes of NAND cells to fit in more of them per layer.

Meanwhile, the 218-layer 3D NAND device features a quad-plane architecture allowing for a higher level of parallelism for programming and read times and increased performance. In addition, the 218-layer 3D TLC device also has a 3200 MT/s (which could provide a 400 MB/s peak read/write speed) input/output interface, which is the highest I/O speed announced so far. High data transfer rates will be handy for high-end client and enterprise SSDs featuring a PCIe 5.0 interface.

The key innovation of the 8th Generation BiCS 3D NAND memory is the all-new CBA (CMOS directly Bonded to Array) architecture that implicates separate production of 3D NAND cell array wafers and I/O CMOS wafers using the most optimal process technologies and then bonding them together to create a final product that offers increased bit density and fast NAND I/O speed. Meanwhile, Kioxia and Western Digital must disclose details about their CBA architecture and whether the I/O CMOS wafers carry other NAND peripheral circuitry, like page buffers, sense amplifiers, and charge pumps.

Producing memory cells and peripheral circuits separately solves several problems as it allows manufacturers to make them using the most efficient process technologies in their sections of cleanrooms. This brings further benefits as the industry adopts methods like string stacking.

Kioxia and Western Digital Fab 7, Yokkaichi Plant, Japan

Kioxia said it had started sample shipments of 8th Generation BiCS 3D NAND memory devices to select customers. Still, there is no word when the company expects to initiate volume production of its next-generation flash memory. It is not unusual for companies to announce new types of 3D NAND quarters before they enter mass production, so it is reasonable to expect 8th Gen BICS on the market in 2024.

"Through our unique engineering partnership, we have successfully launched the eighth-generation BiCS Flash with the industry's highest bit density," said Masaki Momodomi, Chief Technology Officer at Kioxia Corporation. "I am pleased that Kioxia's sample shipments for limited customers have started. By applying CBA technology and scaling innovations, we've advanced our portfolio of 3D flash memory technologies for use in various data-centric applications, including smartphones, IoT devices, and data centers."

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  • sheh - Saturday, April 1, 2023 - link

    Has any other recent press release, by any manufacturer, included P/E specs?
  • back2future - Monday, April 3, 2023 - link

    only found another more theoretical approach from Infineon ~2021 "AN217979 Endurance and Data Retention Characterization of Infineon Flash Memory" ( )
  • back2future - Monday, April 3, 2023 - link

    and a short view on an abstract for "Data-Retention Characteristics Comparison of 2D and 3D TLC NAND Flash Memories" provides with a relation between 1time write and ~300x W/E for 2d-Nand from millenium memory towards 1yr ( )

    but, again, we don't know about controller, firmware or real-life surroundings effects with Nand only theory and laboratory conditions
  • sheh - Monday, April 3, 2023 - link

    Well, for component chips it's expected that this data is published, as the target audience needs to know.

    But it seems these datasheet aren't publicly available? Haven't searched much, but for example, Micron seems to require one to send a "Document Access Request". Was trying to check MT29F1T08EELEEJ4-T (128GB).
  • Silver5urfer - Saturday, April 1, 2023 - link

    Micron lost 2Bn in cash due to loss of NAND demand, and it is projected to have lower demand. I wonder how it will impact the industry. Also a shame that there's no NAND on the planet that can drive the endurance factor likes of Optane and I do not see it happening either. All the new PCIe5.0 NVMe are a joke. No improvements at all barely using the overrated PCIe bus bandwidth as the Random is far more important than the Sequential.

    Plus I will mention again how the Firecuda 530 4TB NVMe is the only TLC NAND that can rival MLC technology. That beast has 5100TBW while the top end SN850X and 990 Pro max out at 1/2 of it at 2400TBW. Pathetic. I got fleeced over the 980 Pro SSD purchase last year with insane cost around $500 for 2TBx2. Today that is almost 1/2 price. And the 530 Firecuda launched at insane rip off junk at $900+ now it is 1/2 at $500 still massively overpriced. I hope the new actively cooled garbage PCIe5.0 SSDs come and reduce the price of the existing PCIe4.0 drives. I do not have hope in Samsung doing anything as their SSDs are plagued with Firmware problems which cause drive wear, lockups and other failures, both 980Pro and 990Pro. Samsung as a brand of reliability and performance has dropped off like a rock only being floated because of the brand name, if they keep pushing garbage, they are going to be irrelevant as the 3rd party Controllers with open NAND market is going to phase their in-house rubbish. Also a sin to name the TLC as Pro.
  • ballsystemlord - Saturday, April 1, 2023 - link

    A lot of people were disappointed that the 980PRO used TLC. And yes, endurance is the last thing they think of because they want you to buy MORE so your SSD must BREAK MORE.
  • FunBunny2 - Monday, April 3, 2023 - link

    "endurance is the last thing they think of"

    again, who are the 'people'? if it's enterprise, all the bean-counters and engineers care about is that the device meets its SLA/warranty lifetime. the device will be replaced at, or nearly, warranty expiration. the company gets to right off the device as an expense, so You The Taxpayer pay for most of it anyway.

    only retail cares about endurance, because we're too poor to do scheduled replacement. which can be a pain in the butt.

    it will be interesting to find out how those Samsung pieces of kit have faired in bidnezz.
  • ballsystemlord - Tuesday, April 4, 2023 - link

    As In, I do a lot of reading of tech articles, SSD reviews, and I talk to geeks. Next time I'll demand names and 3 proofs of identity of "everyone" so you can arrest them for "wrong think" or maybe you want me? IDK. Why not just accept that based on why I have read "people" -- not everyone -- wishes the 980 PRO would have been MLC?
  • ballsystemlord - Tuesday, April 4, 2023 - link

    The average person, in my experience, wants their devices (literally every device) to last well beyond warranty. So "bean counters" don't really factor into the viewpoint of the people I'm talking about.
  • coburn_c - Saturday, April 1, 2023 - link

    Reads like gpt wrote it

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