NAND flash reliability with rank modulation
US9983808B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 2015 |
| Grant date | May 29, 2018 |
| Priority date | — |
| Expiry date | Dec 10, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C16/349
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The reliability of NAND flash memory decreases rapidly as density increases, preventing the wide adoptions of flash-based storage systems. A novel data representation scheme named rank modulation (RM) is discussed for improving NAND flash reliability. RM encodes data using the relative orders of memory cell voltages, which is inherently resilient to asymmetric errors. For studying the effectiveness of RM in flash, RM is adapted to make it simple to implement with existing flash memories. The implementation is evaluated under different types of noise of 20 nm flash memory. Results show that RM offers significantly lower cell error rates compared to the current data representation in flash at typical P/E cycles. RM is applied to flash-based archival storage and shows that RM brings up to six times longer data retention time for 16 nm flash memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.