Micron Announces 32GB 3D NAND Flash – Huge Improvements In Power & Speed

Memory and storage are key components in any modern computer, be it a desktop, laptop, or your humble mobile phone. Packing ever higher densities into some very cramped real-estate, Micron is releasing its new wave of 3D NAND flash chips, with technology co-developed with Intel, to squeeze in as much as 32GB of NAND Flash per chip.

When the landscape becomes packed with no room left to expand, they only way to build is up. This is true for both city planning and electronics. As microprocessors get smaller and smaller, and memory gets denser and denser, there are physical limits to what can be packed into a single chip. The nanometer race is coming to an end, so chip designers are having to leverage new techniques to improve performance and densities.

Instead of building the storage cells on a 2D plane, Micron is stacking them on top of each other to form huge towers (molecularly speaking) of storage and even memory. This isn’t stacking chips either, with multiple layers of silicon being soldered to each other with passthrough connections; these are towers built onto the silicon itself, using standard lithographic techniques.

While significantly increasing density, building up also allows for another benefit, and that’s allowing the cells to be larger (the blocks of transistors that actually hold the charge used for data). Larger cells you ask, isn’t that the opposite of increasing density? While making things bigger is the antithesis of microelectronics, there are some physical problems with building ever smaller, and that’s to do with quantum tunneling – where electrons pass through semiconductors when they’re not supposed to. By making transistors smaller, it becomes easier for electrons to pass through, resulting in corruption of data. By building up, the transistors can be kept bigger, significantly reducing the effects of quantum tunneling, and at the same time, increasing the longevity of the silicon that is used in Flash storage.

But density isn’t everything either, as Micron is rolling out its new chips with a new interface, UFS 2.1, which will eventually replace the more common e.MMC interface. While e.MMC isn’t exactly slow, it’s not very efficient, since it’s a parallel interface and limited to reading or writing (half duplex), rather than both at the same time. UFS is a serial interface that allows full duplex, leading to significant gains in random IO (plus queue management). Micron’s 32GB chips gain a 30% boost in sequential performance, as well as allowing random writes of up to 20,000 IOPS. While the UFS interface allows for up to 700MB/s transfer speeds, the realistic speeds of host controllers will limit throughput to about 450MB/s, which is still significantly faster than old HDDs and e.MMC.

This added speed also has an interesting side effect too, and that’s better power efficiency. While the 3D stacking of the chips increases power savings in of itself, and Micron has even included single-die sleep states too (meaning multi-die solutions can sleep individual parts, rather than wait for the whole storage block to finish); high speed transfers means that the chip can enter sleep states sooner, reducing battery drain.

Beyond the high density 3D NAND chips, is a new set of ultra-low power memory, LPDDR4X – offering a 45% reduction in power compared to non-X LPDDR3/4. When on call with Micron, we were told that the operating voltages of these new chips was an astonishing 0.6V – that’s the forward voltage drop of most diodes in full scale electronics (for those with any interest in electronics).

Combining the the two technologies of 32GB 3D NAND and the new LPDDR4X memory, Micron is really pushing for a single chip solution for modern smartphones in the $200+ range. Using a single chip for storage and memory means less real estate taken up on the PCB, less power used, and ultimately more room for other components or a larger battery. The 8GB 3D NAND chips are tiny, at just over 60mm².

The new chips are already being circulated to production partners and will likely find themselves in devices early next year, after product validation is complete. It probably won’t be long before we start seeing 256GB of internal storage on flagship mobiles – just as well with 4K cameras and panoramic photos being taken for use in VR movies.