Computer

Developed the first flash memory with 7 bits per cell

The news that Microsoft might drop support for conventional hard drives in Windows has many with their hands on their heads. Since if there is any advantage left to hard drives it is how cheap each bit is for storage in comparison. On the other hand, in solid state drives, storing information is still expensive even today. Well, this could change, since they have managed to develop 7 bit per cell flash memory.

One of the biggest challenges facing flash memory of all kinds is storage capacity. The technology to manufacture it is the same as that used to create RAM memories, but the basic structure is more complex. If we add to that that more storage capacity is required, then it is necessary to look for solutions. One of them a few years ago was the development of 3D NAND memory, which consisted of stacking NAND Flash chips one on top of the other and with interconnections that cross them vertically. Today, the vast majority of NVMe SSDs use this technology and the number of layers increases with each generation. The other evolution is to increase the number of bits that can be stored per cell.

What characteristics does 7 bits per cell flash memory have?

In the first place, we must clarify that we are not talking about a final product, but about the fact that KIOXIA has managed to develop in the laboratory NAND Flash memory chips with 7 bits per cell. What does this mean? Traditionally, a memory cell stores a single bit, and therefore a value of 0 or 1. Well, the trick to increasing storage capacity in devices that use this type of memory is to use several different voltages. So that, a cell with 7-bit capacity can store 128 different values. Therefore, this amount of voltage values ​​will be necessary to store such a volume of information.

FLash memory 7 bits per cell voltage levels

Most current NVMe SSDs use 4 bits per cell if they are the most capable. However, we are talking about increasing the storage capacity by 75% only and the complications are in the flash controller. Which has yet to be developed and have the ability to manage all 128 voltage levels precisely. So we could be talking about increasing the processing capacity of these support processors by an order of magnitude.

In any case, the viability of 7-cell flash memory as far as commercial products are concerned is very remote. Not only due to the fact that the controller has not yet been developed, which is the other half of an NVMe SSD by taking care of the data requests of the rest of the system. Rather it is due to the fact that they have managed to make it work under very specific conditions and in the laboratory. Since to do itor have had to submerge the chips in liquid nitrogen at -196 °C for memory cells to work. Which is a very high cost for not even doubling the capacity to store data.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *