Presentation
Adaptive Read Retry Table Extension for Enhanced Data Reliability in 3D NAND Flash Memory
Description3D NAND flash is widely used from PCs to data centers, but its major weakness is data reliability. As data is retained, charge leakage causes read errors. Vendors mitigate this using the read retry mechanism, which iteratively applies predefined read reference voltage combinations, called read retry parameters (RRPs), stored in a read retry table (RRT). However, the limited number of RRPs can lead to RRP burnout, a condition where all read retry parameter entries have been exhausted without successful data recovery.
In such cases, the data becomes undecodable and the corresponding block is marked as bad, degrading both capacity and lifetime of the NAND flash. Experiment showed that even a small portion of recovey failures may lead to significant capacity loss. We propose an Adaptive RRT Extension framework, integrating two key mechanisms: WL-Aware Interpolated Retry (WIR) and Multi-Dimensional Guided Retry (MDGR), to expand recovery capability. Experiments show that our method recovers up to 99\% of failed pages and preserves up to 99\% and 84\% of usable capacity under 12- and 30-month retention, respectively—where the baseline retains only 90\% or reaches end-of-life.
In such cases, the data becomes undecodable and the corresponding block is marked as bad, degrading both capacity and lifetime of the NAND flash. Experiment showed that even a small portion of recovey failures may lead to significant capacity loss. We propose an Adaptive RRT Extension framework, integrating two key mechanisms: WL-Aware Interpolated Retry (WIR) and Multi-Dimensional Guided Retry (MDGR), to expand recovery capability. Experiments show that our method recovers up to 99\% of failed pages and preserves up to 99\% and 84\% of usable capacity under 12- and 30-month retention, respectively—where the baseline retains only 90\% or reaches end-of-life.
Event Type
Research Manuscript
TimeTuesday, July 282:34pm - 2:47pm PDT
LocationMtg Room 203C
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