Micron Announces New 3D NAND Process: Denser, Faster, Cheaper | GeekComparison

Information slide about hard disk.
Enlarge / We are all well acquainted with the Burj Khalifa’s relationship to the Eiffel Tower, right?

On Monday, memory and storage vendor Micron announced that its new 176-layer 3D NAND process (the storage medium underlying most SSDs) is in production and has begun shipping to customers. The new technology should offer higher storage densities and write endurance, better performance and lower costs.

Replacement port architecture

Replacement gate architecture eliminates gaps between cells and the unintended capacitive effect those gaps necessarily cause.
Enlarge / Replacement gate architecture eliminates gaps between cells and the unintended capacitive effect those gaps necessarily cause.

The new NAND process is Micron’s fifth-generation NAND and second-generation replacement port architecture – a replacement for the earlier floating-gate architecture used by both Micron and Intel in the past. In traditional floating gates, insulators separate individual cells, resulting in unwanted capacitance between cells.

Micron’s replacement gate architecture instead builds multiple cells into a single insulating structure, virtually eliminating cell-to-cell capacitance and (according to Micron) increasing endurance, energy efficiency and performance. The company has not yet provided concrete benchmarks that quantify these claims.

Increased number of layers

The new 3D NAND process builds more cell layers into each chip, providing greater storage density, lower access latencies, and better power efficiency. For reference, Micron’s current floating-gate NAND offers 96 layers, the previous generation replacement-gate NAND offered 128, and Western Digital’s BiCS5 3D NAND process offers 112 layers.

A larger number of layers means a significantly smaller mold size with the same number of storage cells. Micron claims the new chips are 30 percent smaller than the top competitive offerings. This makes higher storage capacity more practical in smaller form factors.

We need to be clear, the utility of more storage in smaller form factors means here terribly small form factors such as M.2 NVME drives and integrated eMMC storage. While consumers are accustomed to higher capacity in conventional drives than SSDs, the limitation is cost, not volume. Storage vendor Nimbus began selling a 100TB SSD in the traditional 3.5-inch hard drive form factor more than two years ago; meanwhile, Western Digital did not begin selling conventional 20 TB hard drives until July.

In addition to the increased areal density, Micron says the new process offers significant improvements in both read and write latency — a 35 percent improvement over the current floating-gate NAND and a 25 percent improvement over the former’s replacement port. generation NEN.

The greatest performance gains here are not found in the typical selection of overwhelmingly large numbers favored by marketing departments – that is, the absolute top speed a drive can achieve for extremely large operations under ideal conditions. More importantly, they mean improved Quality of Service (QoS), in other words, more consistent speeds even under less than ideal workloads and conditions.

Micron’s newly improved latencies should also mean better low-end performance, in other words, 4KiB or smaller blocksize operations, not running in massively parallel workloads.

What this could mean for consumers and businesses

If Micron’s claims of greatly increased write endurance prove true, it could become possible to replace incredibly expensive SLC (Single Level Cell) enterprise/data center SSDs with much less expensive 3D NAND devices in demanding applications. Meanwhile, assuming manufacturing costs per wafer don’t rise sharply, the roughly one-third increase in storage density per chip could lead to similarly cheaper consumer devices.

We don’t expect this to be the death knell for traditional hard drives just yet. Even in the best case scenario – no increase in production costs whatsoever – this would put the cost per terabyte of TLC NAND somewhere around $85. The cost per TB of conventional hard drives is around $27, so there’s still plenty of air between the two technologies when it comes to price.

Frame image by Micron

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