Non-Volatile Memory Sub-Block Erase Control for Disturb Reliability
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Solution Overview
Problem
Conventional block-unit control techniques struggle to provide adequate performance as memory blocks increase in size, leading to reliability issues due to disturb deterioration caused by adjacent sub-block operations in non-volatile memory devices.
Innovation Solution
A non-volatile memory device with first and second sub-blocks, each selectable as a unit of an erase operation, and control logic to calculate on-cell and off-cell counts, generate disturb information, and adjust operating conditions based on this information to improve performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory blocks are increased in size to improve storage capacity, then storage capacity is improved, but reliability deteriorates due to disturb deterioration caused by adjacent sub-block operations
Solution Approach 1:
The memory block is divided into multiple sub-blocks (first sub-block and second sub-block) that can be independently operated. This segmentation allows selective erasure of only the required sub-block while protecting adjacent sub-blocks from disturb deterioration, thereby maintaining reliability while supporting large storage capacity through increased block size.
2Quantity of substance
If conventional block-unit control techniques are used for larger memory blocks, then storage capacity is improved, but performance deteriorates due to inadequate control for increased block capacity
Solution Approach 1:
The memory block is divided into multiple sub-blocks (first sub-block and second sub-block) that can be independently operated. This segmentation allows selective erasure of only the required sub-block while protecting adjacent sub-blocks from disturb deterioration, thereby maintaining reliability while supporting large storage capacity through increased block size.
Solution Approach 2:
The control logic dynamically determines which sub-blocks require erasure based on actual data storage needs, rather than erasing entire blocks statically. This dynamic control optimizes performance by minimizing unnecessary erase operations while maintaining adequate control for increased block capacity.
3Productivity
If adjacent sub-block operations are performed, then storage operations are improved, but reliability deteriorates due to disturb deterioration
Solution Approach 1:
Before performing erase operations on a target sub-block, the control logic identifies and protects adjacent sub-blocks by excluding them from the erase operation. This preliminary protective action prevents disturb deterioration in adjacent sub-blocks, maintaining reliability while enabling efficient storage operations on the target sub-block.
Solution Approach 2:
The memory block is divided into multiple sub-blocks (first sub-block and second sub-block) that can be independently operated. This segmentation allows selective erasure of only the required sub-block while protecting adjacent sub-blocks from disturb deterioration, thereby maintaining reliability while supporting large storage capacity through increased block size.
Data Source
AI summary
Provided are a non-volatile memory device, a storage device including the non-volatile memory device, and a method of operating the storage device. The non-volatile memory device includes a memory cell array including first and second sub-blocks that are respectively formed from first and second portions of memory cell strings that extend through a plurality of wordlines stacked on a substrate, the first and second sub-blocks each being selectable as a unit of an erase operation; and control logic configured to calculate an off-cell count based on a first voltage for a plurality of memory cells in the first sub-block, calculate an on-cell count based on a second voltage for the plurality of memory cells, and control an operation for the first sub-block to be performed based on an operating condition corresponding to disturb information generated by the off-cell count and the on-cell count.