SSDs: Micron’s 3D-NAND v6 stacks 232 storage layers
Micron is the first manufacturer to bring NAND flash with more than 200 layers. The interface speed increases to 2.4 GT/s in line with PCIe 5.0 controllers.
The new version 6 of Micron’s NAND flash has 232 layers of flash memory, 56 layers more than version 5. The company has started production, and the first SSDs with the new memory are expected to be on the market shortly – but mass production is only to start to start later this year.
As usual, the 3D memory is made up of two parts, each part containing 116 layers of flash memory in this version; underneath is the CMOS control (CMOS under Array, CuA). Micron increases the speed of the interface according to the Open NAND Flash Interface (ONFI) 5.0 standard to 2.4 GB/s, which matches the already introduced E26 PCIe 5.0 controllers from Phison.
speed boost
The real speed of a die is said to be twice as high when writing as its predecessor, and Micron promises an acceleration of 77 percent when reading. The power consumption of the interface drops by more than 30 percent due to the reduction in voltage.
According to Micron, a design with six planes per die is being used for the first time, up to now a maximum of four has been usual for NAND flash. Manufacturers combine a number of NAND blocks into such plans. Because planes are separately addressable, there are fewer collisions when reading and writing simultaneously; the IO performance in mixed operation should thus increase.
Micron sees itself as a pioneer in the NAND flash market due to the high number of layers and the resulting high memory density. Micron currently wants to build 3-bit TLC flash with a capacity of 1 terabit, which results in a storage capacity of 2 TB with 16 dies in one component. The resulting chips occupy 11.5mm × 13.5mm, making them 28 percent smaller than the previous version, according to the company. In an interview with voonze online, Micron manager Alvaro Toledo did not want to rule out a version with QLC flash, i.e. 4 bits per cell, but the company is currently starting with TLC flash.
