SK Hynix Reveals 238-Layer 3D NAND: Cheap and Fast SSDs Incoming

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By Anton Shilov
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SK Hynix increases number of 3D NAND layers to 238.

SK Hynix
(Image credit: SK Hynix)

SK Hynix has introduced its first 3D NAND device featuring 238 layers, the highest number of layers in the industry. The new 512Gb devices promise to be rather cheap and will enable SK Hynix to build inexpensive solid-state storage. Also, 512Gb 238-layer 3D NAND products will help the memory maker learn how to mass produce flash memory with a high number of layers.  

SK Hynix's first 3D NAND device with 238 layers features a triple level cell (TLC) architecture, a capacity of 512Gb (64GB) as well as a 2400 MT/s interface speed, a 50% increase compared to previous-generation flagship NAND from the South Korean manufacturer. As an added bonus, the new 3D NAND memory device reduces power consumption during reads by 21%, which will be an advantage for mobile PCs as well as smartphones. 

The IC features a charge trap flash (CTF) design as well as SK Hynix's peripheral under cells (PUC) layout that the company formally calls ‘4D’ NAND. The company's peripheral under cells (PUC) allows to reduce costs of NAND memory by making devices slightly smaller. 

Formally, SK Hynix's 238-layer 3D NAND devices are more technologically advanced than Micron's 232-layer 3D NAND ICs introduced in July. Micron's 232-layer 3D NAND devices feature a 1Gb capacity and therefore provide more storage space per chip and enabling to build 3D NAND packages of up to 2TB. Yet, SK Hynix says that its 1Gb 238-layer 3D NAND products will be introduced already next year.

In fact, 512Gb 238-layer 3D NAND devices may have certain advantages over 1Gb 232-layer 3D NAND ICs when it comes to building fast midrange SSDs (that have all chances to enter our best SSDs list). Eight 512Gb 3D NAND devices allow to build 512GB drives will all eight NAND channels active and therefore provide maximum parallelism and performance possible at a relatively low cost.

SK Hynix plans to start mass production of 238-layer 3D TLC NAND devices (or 4D NAND, if you prefer) in the first half of 2023. The new flash memory ICs will be initially used for client SSDs, later on it will be adopted for smartphones as well as for datacenter-grade drives.

Anton Shilov
Anton Shilov
Freelance News Writer

Anton Shilov is a Freelance News Writer at Tom’s Hardware US. Over the past couple of decades, he has covered everything from CPUs and GPUs to supercomputers and from modern process technologies and latest fab tools to high-tech industry trends.

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3 Comments Comment from the forums
  • bit_user
    I think the article says "1 Gb" in several places where it ought to say "1 Tb".
    Reply
  • MeeLee
    "4D NAND"???
    Let's not get ahead of ourselves, just because someone does 238 layers of what initially started as SLC, and evolved to DLC, TLC and now MLC.
    MLC nand, be it 3D or regular, can have a very large amount of layers. To become 4D nand, it'd have to shape shift in our realm, and I don't see that happening anytime soon.
    Reply
  • bit_user
    MeeLee said:
    "4D NAND"???
    Let's not get ahead of ourselves, just because someone does 238 layers of what initially started as SLC, and evolved to DLC, TLC and now MLC.
    MLC nand, be it 3D or regular, can have a very large amount of layers. To become 4D nand, it'd have to shape shift in our realm, and I don't see that happening anytime soon.
    I sympathize with your sentiment, but just want to point out that I think the PUC is how they justify calling it "4D". Not that it makes much more sense, but I guess the idea is they're not only stacking layers of NAND, but also putting the controller underneath it all. So, that extra degree of stacking somehow qualifies it as "4D".

    Or, maybe it's intended to refer to the fact that they're packing multiple bits per cell. So, to address a bit, you'd need to specify the: plane, x coordinate, y coordinate, and which bit in the cell. However, I think it's not their first 3D TLC or at least MLC chip, so it's a little hard to see why it would suddenly now qualify as 4D.

    Another way you can justify calling something "4D" is if the interconnect topology warrants it. But nothing about that is mentioned.
    Reply