A Scalable Bidimensional Randomization Scheme for TLC 3D NAND Flash Memories

Abstract

Data randomization has been a widely adopted Flash Signal Processing technique for reducing or suppressing errors since the inception of mass storage platforms based on planar NAND Flash technology. However, the paradigm change represented by the 3D memory integration concept has complicated the randomization task due to the increased dimensions of the memory array, especially along the bitlines. In this work, we propose an easy to implement, cost effective, and fully scalable with memory dimensions, randomization scheme that guarantees optimal randomization along the wordline and the bitline dimensions. At the same time, we guarantee an upper bound on the maximum length of consecutive ones and zeros along the bitline to improve the memory reliability. Our method has been validated on commercial off-the-shelf TLC 3D NAND Flash memory with respect to the Raw Bit Error Rate metric extracted in different memory working conditions.

Editorial for the Special Issue on Flash Memory Devices

“…This Special Issue provides insight on and advancements in Flash memory devices. There are nine papers including one review paper, covering the reliability of 3D NAND Flash devices [1][2][3], the characterization and design of Flash memory cell/string [2,4,5], NOR Flash memories for embedded applications [5], a set of Error Correction Codes and Secondary Correction Algorithms for flash memories [6,7], Flash management through flash signal processing in controllers for Big Data storage [6][7][8], and the impact of Flash memories on Solid State Drives reliability and performance [8,9].…”

“…The physics of devices and the higher abstraction levels of the digital electronics come together in this context. In [8], M. Favalli et al discussed the data randomization for reducing or suppressing errors. In this work, they proposed a randomization scheme that is easy to implement, cost effective, and fully scalable with memory dimensions and guarantees optimal randomization along the wordline and the bitline dimensions.…”