
For several decades, NAND Flash has been the primary technology for low-cost and large-density data storage applications ….
This non-volatile memory is present in all major electronic end-use markets, such as smartphones, servers, PCs, tablets, and USB drives. In the conventional computer memory hierarchy, NAND Flash is located the furthest away from the central processing unit (CPU) and is known to be relatively inexpensive, slow, and dense compared to static random-access memory (SRAM) and dynamic RAM (DRAM).
The success of this storage technology is related to its ability to scale density and cost continuously – the main drivers for NAND Flash technology development. About every two years, the NAND Flash industry has substantially improved bit storage density, expressed in terms of increasing Gbit/mm2.
Several technological innovations have been introduced along the road to maintain this trendline. The transition to the third dimension was arguably the most impressive innovation. In 3D NAND Flash, the memory cells are stacked to form a vertical string, and cells are addressed by horizontal word lines. Other notable innovations include increasing the number of bits per cell (up to four) and transitioning from the floating gate transistor to the charge trap cell for memory operation.
Learn more about the NAND technologies that will come over the next years
