This week, Western Digital revealed its 3D NAND reminiscence improvement plans for the approaching years. Amongst different issues, the corporate famous that, along with its accomplice Japanese firm Kioxia, it’s creating 162-layer flash reminiscence chips with a lowered cell space and high-performance flash reminiscence with greater than 200 layers.
Subsequent-generation 3D NAND reminiscence BiCS6 will seem in the direction of the tip of this 12 months. At first look, these won’t be essentially the most superior chips when it comes to the variety of vertical layers – solely 162 layers, which seems to be fairly modest in opposition to the background of the 232-layer 3D NAND chips simply launched by Micron. Nevertheless, the capability of WD and Micron options is identical – 128 GB (1 Tbit). A space BiCS6 and would be the most compact within the business 68 mm2. The corporate was in a position to obtain this by considerably decreasing the bodily dimension of the reminiscence cells, which was helped by way of a brand new materials of their construction.
As well as, the BiCS6 reminiscence will retailer 4 bits in every cell (QLC). Lowering the bodily dimension of the cell with a mixture of writing 4 bits to every of them ought to result in a lower within the variety of rewrite cycles, however WD has not but disclosed this worth. On the identical time, the pace of BiCS6 reminiscence guarantees to be 60% larger than within the case of recent options, which is able to enable it for use each for the manufacturing of mass drives and capacious server SSDs. Growing the density must also scale back the price of manufacturing, which is necessary for everybody.
One other new improvement seems to be no much less attention-grabbing – BiCS + reminiscence with greater than 200 layers. It’s claimed that it’s being developed from scratch primarily for server-side SSDs. BiCS+ reminiscence will seem by 2024 and can present as much as 55% extra bits per platter in comparison with BiCS6 reminiscence, in addition to a 60% improve in pace. Additionally, the write pace will improve by 15%, which isn’t any much less necessary for NAND flash reminiscence than the whole lot else.
Going ahead, WD, like different 3D NAND distributors, is aiming for 500 or extra 3D NAND layers. Such reminiscence can solely be produced utilizing a mixture of many applied sciences, together with vertical “gluing” of reminiscence crystals. The corporate doesn’t lose hope of releasing reminiscence with 5 bits per cell (PLC), however it’s no more easy than releasing 3D NAND with 500 layers, which delays the time of its look.