The developments in the NAND FLASH segment (the storage chips in your SSD) over the years have astonished and astounded many. The effort to get more cells into one package to achieve bigger and cheaper production soon will reach new heights. 

Toshiba and its strategic partner Western Digital are nearly done with the latest iteration: 128-layer 3d NAND. A year ago we were at 48 and 64 layers NAND. This year 96-layers is the development and yeah the industry never stops as 128-layers are coming to town. Basically with 128-layer NAND you can double up that (example) single 32 GB NAND IC towards 64 GB in the same yet slightly thicker package size.

Toshiba in cooperation with Western Digital (and we assume Sandisk) now are actively developing BiCS-5 NAND. A 128-layer die will be BiCS-5 in Toshiba flash generation naming terminology – BiCS-4 is 96-layer and BiCS-3 is 64-layer. The first NAND packages are to be offered as a 512 Gbit package (512/8 =64GB) based on 3-bits per cell (TLC). 

Toshiba can achieve this by adding third more layers over the 96-layer version. That results in 128-layers. It is expected that BiCS-5 NAND will reach volume production next year with high volume the following year.

64-layer Vertically Stacked NAND? That's old news, 128 layers coming.