Mapping physical memory species
Mas -ROM Fuse, OTP
ROM (NV) Write=1-106
W r i t e > 1 0 1 6
Figure 6. Comparison of NVRAM Technologies
NAND FLASH MEMORY
Significant developments in NAND flash memory over the past few years are resulting in high- density, low-power, and low-cost storage solutions that are enabling the replacement of traditional hard-disk storage with solid-state disks (SSDs). At ISSCC 2011, a 64Gb/die capacity will be demonstrated using 24nm technology with 2b/cell operation. With physical scaling down accompanied by advancing multi-level-storage-cell concepts, a 64Gb/die capacity has been demonstrated in 24nm technology with 2 bits/cell operation. Figure 7 shows the observed trend in NAND flash capacities presented at ISSCC over the past 17 years. Unfortunately, as process feature size shrinks, error rates continue to rise, requiring system designers to develop more- sophisticated controllers to offset this issue, some of which are utilized outside the NAND silicon in the system memory controller.