Nonvolatile Memory Read Compensation for Adjacent Cell Interference
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Solution Overview
Problem
Nonvolatile memory devices face interference issues from adjacent cells during programming, leading to changes in threshold voltage distributions and potential data corruption due to electromagnetic interference, especially as devices are scaled down and memory cells become closer, affecting programming reliability.
Innovation Solution
A nonvolatile memory device with a memory block and reading circuitry that includes alternating bit lines and page buffers, where the second memory cell is read and its bit line is precharged or discharged based on its programmed state to compensate for interference and accurately read the first memory cell, thereby maintaining the original threshold voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cells are scaled down to achieve higher integration density, then integration density is improved, but electromagnetic interference between adjacent cells increases causing threshold voltage changes and data corruption
Solution Approach 1:
The patent applies preliminary action by performing a read operation on the second memory cell before reading the first memory cell. This preliminary read allows the system to detect the programmed state of the second cell and anticipate its electromagnetic interference effect on the first cell. Based on this detection, the system can pre-adjust the read voltage or timing for the first cell, thereby compensating for the threshold voltage shift caused by the adjacent cell's programmed state before the interference fully manifests during the read operation.
2Adaptability or versatility
If the second memory cell is programmed into certain states (PV1 or PV3), then programming capability is improved, but electromagnetic interference to the adjacent first cell increases causing threshold voltage changes
Solution Approach 1:
The patent implements feedback by using the read result of the second memory cell to adjust the read operation of the first memory cell. The system reads the second cell's state, uses this information as feedback, and accordingly modifies the read voltage, timing, or other parameters for reading the first cell. This feedback mechanism allows the system to adapt to the electromagnetic interference conditions created by different programmed states of the second cell, ensuring reliable data retrieval from the first cell regardless of the second cell's programming state.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the reliability of reading operations by compensating for threshold voltage changes caused by electromagnetic interference, ensuring accurate data retrieval even when adjacent cells are programmed into states that induce significant interference.
Implementation Method 1
a memory cell can be easily affected by capacitive coupling with adjacent memory cells
Data Source
AI summary
In a nonvolatile memory device and operating method thereof, data programmed into a second memory cell is sensed and a first memory cell adjacent the second memory cell is read in accordance with the data sensed from the second memory cell.