Western Digital, Intel and Kioxia were all talking about 5-bit penta level cell (NAND) memory. The new type of memory, which uses 4 bit HDD, is 25% more powerful and 25% more efficient than the old one. It’s not surprising, then, that there has been no news regarding the PLC since 2019. Kioxia suddenly spoke not about 5-bit but 7-bit NAND memories, which could be used to build a high-end SSD.
The 7-bit NAND is currently plagued by many issues. A NAND cell capable of accommodating more than one bit must be capable of sustaining multiple voltage levels. This is 16 levels for a 4-bit QLC-memory. It is 64 levels for 6 bits and 128 voltages for 7 bits. This creates significant problems in choosing the right materials to produce memories.
A controller that uses very advanced technology can handle up to eighty-six voltage levels. This controller costs about the same as a processor.
Kioxia currently has 7-bit-based work-assisted SSDs. These inventions should not be used in the field. To stabilize the chips and lower the voltage requirements, the chips were sprayed with liquid nitrogen and frozen at -196C. This means that the superconductor’s state allowed you to achieve a lot of memory.
This could lead to 7-bit memory loss. Although we believe that Kioxia is capable of making such a memory function at normal temperatures, there are still many challenges to be overcome, including a complex controller and low operating speeds. This is a significant increase in density, only 65% more than the current QLC.