SK Hynix shipping 96-layer QLC 4D NAND flash to SSD controller firms

SK Hynix announced that it has begun sampling its 96-layer 4D NAND flash chips to its customers. The new samples include a 1-terabit (Tb), Quad Level Cell (QLC) memory die that will target next-generation and high-capacity QLC-based SSD products that customers are expected to purchase to replace their old HDDs.

QLC-Based SSDs on the Horizon

Last year, SK Hynix introduced its new 96-layer 4D NAND flash technology, meant to compete with similar 96-layer 3D NAND flash technologies from other storage technology suppliers. Its goal was to allow for a more seamless transition to QLC flash technology (generally known as less reliable than TLC or MLC) with good enough reliability for most mainstream consumers. 

The QLC technology can store four bits into a single flash cell, which means that 33% more bits can be stored into a new flash drive with the same number of cells. With the introduction of 96-layer flash chips, even higher density can be achieved in next-generation flash products compared to SK Hynix’ previous 72-layer products.

SK Hynix calls its technology 4D NAND because it uses a combination of 3D Charge Trap Flash technology (CTF) as well as Periphery Under Cell (PUC). According to the vendor, using 96-layers can achieve 49% improved bit density over the company’s previous 72-layer 3D NAND products.

Wallace Kou, CEO of Taiwan-based SSD firm Silicon Motion Technology, in a statement accompanying announcement said he was “impressed” by the performance of SK Hynix’s QLC chip and that the samples met its clients requirements.

SK Hynix also plans to develop its own QLC software algorithm and controller and launch its own QLC-based SSD product next year, when demand for QLC drives should become significant.

According to IDC data cited in the announcement, QLC’s share in the NAND flash market is expected to increase from 3% in 2019 to 22% in 2023. The enterprise SSD market is expected to have a compound annual growth rate (CAGR) of 47.9%, which should to a rapid replacement of HDDs in a span of five years.

SK Hynix originally promised to ship 512 Gb (64GB) 96-layer flash dies and 1 Tb, 128-layer flash dies later into the future, but it seems the company is becoming more aggressive with its roadmap.

SSD prices have been in free fall since last year, and it looks like this decline will continue for at least for the rest of the year. Furthermore, competitors are starting to launch QLC drives that tend to come in higher capacities than TLC drives, which puts pressure on the price of all types of SSDs.

QLC drives, at least the first generations, will not be able to sustain too much writing on them, so their primary target will be customers that want to use the high-capacity QLC drives for long-term storage or backup as they replace their HDDs. However, that doesn’t mean that the higher value of QLC drives per GB won’t affect the prices of TLC and MLC drives.

Most mainstream users may not be able to tell the difference. Sales of cheaper QLC drives will force TLC drive makers to both lower their prices, as well as try to move on to QLC technology as soon as possible.