SK Hynix just announced that the company has begun mass production of its ultra-fast 238-layer TLC NAND memory. Thanks to greatly improved density and speeds of 2400 MT/s, the new NAND will be suitable for high-end PCI-Express 5.0 SSDs.

The first 238-layer 3D TLC NAND from SK Hynix is a 512 Gb (64 GB) capacity product. The NV-LPDDR4 signaling method with the ONFI 5.0 interface enables the device to achieve a 21% lower power consumption during read operations and a 2400 MT/s interface transfer rate, implying a 50% increase.

Compared to the 176-layer predecessor, the new NAND offers additional advantages, including a 34% higher manufacturing efficiency due to a smaller die size. This also lowers the overall material usage and cuts back on expensive processing steps.

Enabling Faster Consumer SSDs

SK Hynix’s 238-layer 3D TLC NAND uses the string stacking process to combine two 119-layer stacks. This architecture, referred to as “4D NAND”, integrates a charge-trap CMOS under Array (CuA) layout that places the NAND logic beneath the 3D NAND memory cells array, resulting in a smaller die size and lowering costs.

SK hynix 3D TLC NAND Specs238-Layer NAND176-Layer NAND
Decks2 (x119)2 (x88)
Die Capacity512 Gbit512 Gbit
Density (Gbit/mm2)~14.3910.8
Die Size (mm2)35.58mm2~47.4mm2
I/O Speed2.4 GT/s
(ONFi 5.0)
1.6 GT/s
(ONFI 4.2)

The new SK Hynix NAND will become an important competitor to Micron, which has so far dominated the 238-layer 3D TLC NAND arena. Early PCI-Express 5.0-enabled solid state drives have used a 1600 MT/s interface, limiting performance to around 10 GB/s sequential read/write transfers. To increase the speed to 12.5 GB/s and beyond, higher-speed memory is one of the key components required.

Mass production of SK Hynix’s 238-layer NAND started in May. According to the company, the products boast world-class competitiveness in terms of price, performance, and quality when compared to the 176-layer NAND from the previous generation. This is also anticipated to have a positive effect on corporate earnings in the second half of the year.