Non-volatile Memory Data Recovery via Aggressor Group Segmentation
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Solution Overview
Problem
Threshold voltages of multiple programmed memory cells in non-volatile memory devices can change over time due to retention, floating gate coupling, or charge loss, leading to deteriorated reliability of read data.
Innovation Solution
A non-volatile memory device and read method that perform a data recovery operation for multiple aggressor groups without increasing the device area, by applying specific read levels to adjacent word lines and recovering data based on obtained aggressor group information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data recovery operation is performed for multiple aggressor groups using conventional methods, then data reliability is improved, but device area increases due to additional storage latches
Solution Approach 1:
The read operation is segmented into multiple phases, where aggressor group information is obtained first, then used to guide subsequent read operations for different aggressor groups. This segmentation allows data recovery without requiring all aggressor group data to be stored simultaneously in latches
Solution Approach 2:
Aggressor group information is obtained in advance before performing the actual read operation for data recovery. This preliminary action allows the system to adapt the read operation based on the specific aggressor group characteristics, enabling effective data recovery without additional storage latches
2Reliability
If the number of aggressor groups is increased to handle more threshold voltage variations, then data reliability is improved, but device complexity increases due to more storage latches required
Solution Approach 1:
The read operation is made dynamic by adapting the read levels and operations based on the obtained aggressor group information. The system dynamically adjusts the read strategy for each aggressor group rather than using a static approach that would require fixed storage for all possible groups
Solution Approach 2:
Read levels are changed and adjusted based on the specific aggressor group being read. The system modifies read operation parameters (read levels) according to the aggressor group characteristics, enabling effective data recovery without requiring additional storage infrastructure
Data Source
AI summary
A non-volatile memory device receives a read command and an address from a controller, and performs a data recovery read operation in response to the read command. In the data recovery read operation, an operation of obtaining aggressor group information from a memory cell connected to a word line adjacent to a word line selected according to the address, and an operation of recovering data corresponding to the obtained aggressor group information in a memory cell connected to the word line selected according to the address, are repeatedly performed on each of a plurality of aggressor groups.