back to article 72-layer flash die from SK Hynix towers over all, capacity a bit meh

Korean flash fabber SK Hynix has built a 72-layer 3D NAND die with 256Gb capacity. That number of layers, in effect a higher-rise flash chip than anybody else has built, is impressive but the 256Gb capacity is not; Toshiba's 64-layer flash die has a 512Gb capacity. Like the SK Hynix chip, it is a TLC (3bits/cell) device. It …

  1. Anonymous South African Coward Silver badge

    Wow - imagine cramming a whole 2Tb into your phone/phablet... (iThings purposefully not mentioned)

    Just makes you go WTF when you look at existing 64Gb~128Gb CF cards...

    Heck, I'm getting flashbacks from the DOS days with 10Mb and 20Mb HDD's...

    1. This post has been deleted by its author

    2. Ken Hagan Gold badge

      Mind you don't confuse your little b with a big B. These numbers aren't that much bigger than what you get in current tablets.

      1. short

        These numbers are really quite high for a single die. High capacity nand chips tend to have a bunch of (back-ground, so they're waffer-thin) die stacked on top of each other, and a bit of cunning electronics to make it look like one honkin' great device, all in a bit of black plastic with some balls on the bottom. Tablets will then often have a (small) number of these packages to reach the numbers they want.

  2. Stefan 2

    But 72 layer though...

    Surely means that they are employing some ECC technique if they are only realising an even 256Gb per die.

    1. Ken Hagan Gold badge

      Re: But 72 layer though...

      Not sure about that. A 9:8 ratio of physical capacity to advertised capacity could just be the spare pages that they keep to replace worn out ones.

  3. Warm Braw Silver badge

    That number of layers ... is impressive but the 256Gb capacity is not

    IMHO it's still a fuck-off NAND die...

  4. druck


    Two times = twice

    1. John H Woods Silver badge

      Re: "Two times = twice"

      Really? I challenge you to find me a native speaker who would prefer "twice faster" to "two times faster"

      1. Steve Foster

        Re: "Two times = twice"

        I would much prefer "twice as fast" over "twice faster", but there are sentences where that would not fit properly, and "two times faster" would be the appropriate choice.

        In the article sentence, both "twice as fast" and "two times faster" are acceptable alternatives.

  5. MrRimmerSIR!

    What's the TBW?

    Presumably, a larger cell size means more writes before it dies?

    1. Snowy

      Re: What's the TBW?

      Just what I was thinking, have an upvote/

  6. short

    Testing these things

    How long does it take to test these once they're fabbed? How many times round do you have to go, erasing, writing, checking and building the bad block list?

    Even if you're rocking along flat out, 32GBytes is a lot of space to work through.

    (I miss the bad sector lists that used to be printed on HD labels. Maybe if they wrote really, really small.)

    Is it possible to see any of this structure in a die shot, or does it just look like a regular NAND device, and you can't see under the top layer?

    Ah, some die shots back here. Mildly interesting, want more!

    also, 4.3Gb/mm^2 . Lordy.

  7. a_mu

    this can't go on for long

    Hassle I see, is

    every doubling of capacity , doubles the height of the die,

    4 more generations and one will need 26873856 dies in a stack !

    1. short

      Re: this can't go on for long

      These aren't stacked die, they're grown layers on the same die, if I'm understanding right.

      Thin, thin layers. What I'm wondering is - what's the limit? Do earlier layers diffuse a bit, each time through the oven? It can't be that the layers interfere - 48 layers is close to 'n'...

      1. Kevin McMurtrie Silver badge

        Re: this can't go on for long

        Stacking the dies comes next. Need to make that little 'b' a big 'B'.

        1. short

          Re: this can't go on for long

          reckons a stack of 32 layers is 4um high, and you can stack stacks more or less forever.

          I look forward to a PLCC-thickness package, with the middle 2mm made of 16000 layers of storage.

          Sure, it'll take a while to fab, format and test, but that's a lot of data.

          Anything to stop us growing a few dozen layers of NAND over a microcontroller, to save dicking about with external storage? Maybe a layer or ten of DRAM, too? Surely that's much the same process...

  8. Kevin McMurtrie Silver badge

    The cloud! Won't somebody think of the cloud!

    Google, Apple, Amazon, and media rights managers have been telling everybody to stream from the cloud and pay monthly fees for everything. Now storage is fighting back.

    I already have a 200 GB microSD card in my phone for offline everything. IT departments don't like streaming music and the best time to have a map and a copy of Wikipedia is when you're in the middle of nowhere without a signal.

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