https://www.pcgamer.com/intel-and-micron-tag-team-industrys-first-qlc-nand-flash-memory-for-ssds/

Intel and Micron have jointly announced the production and shipment of the industry's first 4-bits-per-cell 3D NAND flash memory, also known as QLC (quad-level cell), which is even denser than TLC (triple-level cell) NAND flash memory that's commonly found on many of the less expensive solid state drives on the market.

"With the introduction of 64-layer 4bits/cell NAND technology, we are achieving 33 percent higher array density compared to TLC, which enables us to produce the first commercially available 1 terabit die in the history of semiconductors," said Micron Executive Vice President, Technology Development, Scott DeBoer.