Memory Cell Group Sensing for Threshold Valley Read Accuracy
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in accurately determining the valley value of threshold voltage distributions due to charge loss over time, leading to increased read errors and inefficiencies in read operations.
Innovation Solution
A method is introduced to divide memory cells into multiple groups and perform sensing operations simultaneously, adjusting discharge times for each group to efficiently determine the valley value of threshold voltage distributions using BL modulation, thereby reducing operation time and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If memory cells are read over time, then charge loss occurs leading to inaccurate threshold voltage determination, but performing multiple read operations increases read errors and reduces reliability
Solution Approach 1:
The patent divides memory cells into multiple groups (first memory cell group, second memory cell group, etc.) and performs sensing operations on each group at different time points. This segmentation allows the system to track threshold voltage changes over time without requiring multiple reads of the same cell, thereby maintaining measurement precision while improving reliability by avoiding repeated read disturbances.
Solution Approach 2:
The patent performs preliminary sensing operations on different memory cell groups at different times to establish baseline threshold voltage distributions. By preparing multiple groups with different read counts in advance, the system can determine valley values without requiring subsequent repeated reads of the same cells, thus preventing charge loss accumulation and maintaining read reliability.
2Measurement precision
If multiple sensing operations are performed to determine valley value, then read operation time increases, but this leads to charge loss and reduced measurement accuracy
Solution Approach 1:
The patent segments memory cells into multiple groups and distributes sensing operations across different time points. Instead of performing multiple sequential reads on the same cells, the system performs one read operation per group at different times, significantly reducing total operation time while maintaining accurate valley value determination through statistical analysis of the distributed measurements.
Solution Approach 2:
The patent implements continuous monitoring of threshold voltage distributions across multiple memory cell groups at different time points. This continuous action allows the system to capture threshold voltage changes over time without interrupting the measurement process, thereby determining valley values efficiently without requiring repeated time-consuming read operations on the same cells.
3Measurement precision
If read operations are performed repeatedly to ensure accuracy, then charge loss accumulates leading to increased read errors, but reducing read operations compromises measurement accuracy
Solution Approach 1:
The patent divides the measurement task across multiple memory cell groups, where each group is read once at a specific time point. This segmentation ensures that each cell undergoes only a single read operation, preventing charge loss accumulation and minimizing read errors while maintaining measurement accuracy through the statistical aggregation of results from multiple groups.
Solution Approach 2:
The patent introduces time as an intermediary dimension for performing sensing operations. By distributing read operations across different time points on different cell groups, the system can accurately determine threshold voltage distributions without repeatedly disturbing the same cells. Time acts as a mediator that allows multiple measurements without increasing charge loss, as each cell is measured only once at its specific time point.
Data Source
AI summary
Examples of the present disclosure provide a memory device and an operating method thereof, a memory system, and an electronic device. The memory device comprises: a memory cell array; and peripheral circuit coupled to the memory cell array through word lines and bit lines and configured to: apply a first read voltage to a selected word line; charge the sense nodes corresponding to the memory cells coupled to the selected word line; divide the memory cells coupled to the selected word line into multiple memory cell groups to perform sensing operations, and the sensing operation includes: controlling the multiple sense nodes corresponding to the multiple memory cells in the memory cell group to discharge twice; and obtain a first counted number of each memory cell group based on each discharge result of the multiple sense nodes corresponding to each memory cell group.