Memory Page In-Place Refresh for Data Retention Recovery
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Solution Overview
Problem
Non-volatile memory devices face issues with data retention and Vt shifts leading to increased fail bit count and bit error rates, necessitating data relocation which increases undesirable cycling of memory cells.
Innovation Solution
Implement a memory apparatus with memory cells grouped into blocks and pages, allowing for in-place refresh of pages to maintain data integrity without relocating data, thereby reducing unnecessary cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is relocated to ensure integrity due to data retention problems, then data reliability is improved, but memory cell cycling increases
Solution Approach 1:
The memory array is divided into multiple blocks, and within each block, pages are segmented that can be independently refreshed. This allows selective in-place refresh of only the affected pages within a block without relocating data across blocks, thereby maintaining data integrity while minimizing overall memory cell cycling.
Solution Approach 2:
The system performs periodic readout operations to detect data retention issues before they become critical. When degradation is detected, the system initiates in-place refresh operations proactively, preventing data integrity failures without needing to relocate data, thus avoiding additional cycling.
2Duration of action of moving object
If in-place refresh is performed to maintain data integrity, then memory cell cycling is reduced, but system complexity increases
Solution Approach 1:
The control means is designed to perform multiple functions: it conducts periodic readout operations to monitor data integrity, detects retention issues, and executes in-place refresh operations. This multi-functional approach consolidates what would otherwise require separate dedicated circuits, managing system complexity while enabling comprehensive data retention management.
Solution Approach 2:
The system implements a feedback loop where periodic readout operations continuously monitor data retention status. When degradation is detected, the control means triggers in-place refresh operations, and the process repeats. This closed-loop feedback mechanism automates data retention management, reducing the need for complex manual intervention or overly sophisticated prediction systems.
3Reliability
If periodic readout is performed to detect data retention issues, then data reliability is maintained, but time consumption increases
Solution Approach 1:
Instead of performing readout operations on all pages of all blocks every time, the system selectively reads only the specific pages within blocks that are suspected of having retention issues. This partial action approach reduces the total time required for monitoring while maintaining effective data reliability checks.
Solution Approach 2:
The system performs readout operations at periodic intervals rather than continuously. This periodic sampling approach allows the system to detect data retention degradation trends over time without the time penalty of continuous monitoring, balancing reliability maintenance with time efficiency.
Data Source
AI summary
A memory apparatus includes memory cells each configured to retain a threshold voltage corresponding to one of a plurality of data states. The memory cells are grouped into a plurality of blocks storing data arranged in a plurality of pages. The memory apparatus also includes a control means configured to perform a readout the plurality of pages of the data of a first one of the plurality of blocks of the memory cells. The control means is further configured to program at least one of the plurality of pages of the data to a second one of the plurality of blocks. The control means is also configured to refresh a remainder of the plurality of pages other than the at least one of the plurality of pages in place in the first one of the plurality of blocks.