A 1.67Tb, 5b/Cell Flash Memory Fabricated in 192-Layer Floating Gate 3D-nand Technology and Featuring a 23.3 Gb/mm² Bit Density

We present the industry’s first 5b/cell (PLC) NAND chip, fabricated in a 192-layer floating-gate (FG) technology. With a die capacity of 1.67 Tb and an area of 73.3 mm ² , it delivers a record bit density of 23.3 Gb/mm ² . Key innovations to enable reliable PLC operation and the features implemented to support system-level usage are described. These include: a fast soft-bit read algorithm capable of handling the presence of defective bitlines; a fast read-calibration algorithm; a reverse-read waveform to improve the read margin; SLC-write-through; and program suspend and resume algorithm compatible with the above read operations.