SK Hynix announces 8th-generation 3D NAND flash
Recently, at the ISSCC 2023 conference, SK Hynix unveiled its latest breakthrough in 3D NAND flash memory development. SK Hynix noted that a team of 35 engineers contributed to the materials presented, introducing a novel 3D NAND flash prototype with a stack layer count exceeding 300.
As reported by TechPowerUp, this 8th-generation 3D NAND flash from SK Hynix features a 1 Tb (128 GB) capacity, triple-level cells (TLC), and a bit density of over 20 Gb/mm^2. The chip boasts a 16 KB page size, four planes, an interface transfer speed of 2400 MT/s, and a peak throughput of 194 MB/s—an 18% improvement over the seventh-generation 238-layer 3D NAND flash. The increased density will reduce the cost per Tb during manufacturing, ultimately benefiting consumers through enhanced performance and capacity.
According to SK Hynix, five key technologies were employed in the development of the 8th-generation 3D NAND flash, including the introduction of Triple-Verify Program (TPGM) functionality, which narrows the battery threshold voltage distribution, reduces tPROG by 10%, and subsequently boosts performance. Adaptive Unselected String Pre-Charge (AUSP) is another method that decreases tPROG by approximately 2%. Furthermore, the Programmed Dummy String (PDS) technique minimizes channel capacitance load to expedite tPROG and tR wordline establishment times. Plane-Level Read Retry (PLRR) functionality enables changes to read levels of planes without terminating others, immediately issuing subsequent read commands and ultimately improving Quality of Service (QoS) and read performance.
SK Hynix has not provided a timeline for the release of its eighth-generation 3D NAND flash, but industry insiders estimate that it may not reach the market until late 2024 or sometime in 2025. In the meantime, SK Hynix’s seventh-generation 238-layer 3D NAND flash is expected to be integrated into the production cycle of new flash products launching in 2023.