The big news in NAND this month is all about layers. Chip sizes are constantly revised, especially when it comes to going smaller. However, more problems arise in planar (or 2D) construction as the chips shrink. The closer the cells are to each other, the higher the failure rate. This year, we have seen several announcements from NAND manufacturers regarding their plans for smaller chips. In April, Toshiba and SanDisk announced plans for a 15-nanometer (nm) chip and Micron announced a 16-nm triple-level-cell (TLC) chip for their cost-effective, consumer SSDs through Crucial. Production volumes of the 15-16-nm chips should continue to ramp up through the end of 2014.
Even though planar construction is still the mainstay for NAND, the ever-approaching issues with smaller sizes have pushed manufacturers to shift more and more focus to vertical NAND (V-NAND). Samsung led the way last year by announcing the world’s first V-NAND. That chip contained 24 layers per chip, all stacked vertically, and is intended to help solve the limitations of planar builds. Also, it should help to drive down the costs of planar NAND instead of leveling them off because of the difficulty and expense of constantly shrinking. Just a few months ago, Samsung boosted its stacks up to 32-nm. They have already been shipping SSDs built with the 32-nm V-NAND in its 850 line. When compared to the same size 2D chip, these models can hold more data which brings down the cost per bit.
It is expected that once planar NAND hits the 10-12-nm range, V-NAND will take its place, with the focus on starting at 32 layers to keep things economical. We should still expect 2D and 3D NAND to co-occur for the next few years are more manufacturers move through the conversion process and rearrange or build new facilities. There is also the annual impact that new mobile devices have on the market. Almost all of these devices use NAND in some way and this pulls a large amount of product from channels. As demand increases and more and more devices rely on the non-volatile properties of NAND, companies will continue to innovate and expand their shrinking capabilities.