Memory Device Dummy Voltage Control for Reliability
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Solution Overview
Problem
The reliability of non-volatile memory devices decreases due to process-related features, necessitating new technologies to prevent this decline.
Innovation Solution
A memory device with a control logic that determines and applies a dummy voltage based on the location of a selected word line within a memory NAND string, adjusting voltages for different programming modes and conditions such as Top-to-Bottom or Bottom-to-Top programming, program/erase cycles, and temperature, to improve data storage and retrieval reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the degree of integration of non-volatile memory devices is raised to increase capacity, then the production cost is reduced, but the reliability of the memory device decreases
Solution Approach 1:
The patent applies different dummy voltages to different dummy word lines based on their specific locations within the memory device. First dummy word lines receive a first dummy voltage while second dummy word lines receive a second dummy voltage, creating localized quality differences that address reliability issues in specific regions without affecting the entire device, thus maintaining high capacity while improving reliability.
2Productivity
If the scale of non-volatile memory devices is decreased to increase integration, then the degree of integration is raised, but various reliability problems are discovered
Solution Approach 1:
The patent dynamically adjusts the dummy voltages applied to dummy word lines based on their locations and the programming mode (T2B or B2T). The control logic determines which dummy voltage to apply based on real-time conditions, making the system adaptive and dynamic rather than static, which helps maintain reliability as the device scale decreases and integration increases.
3Device complexity
If a uniform dummy voltage is applied to all dummy word lines, then the control logic is simple, but the reliability is compromised due to process features
Solution Approach 1:
The patent divides dummy word lines into different groups based on their locations (first dummy word lines and second dummy word lines) and applies different dummy voltages to each group. This local differentiation improves reliability by addressing process-specific issues in specific regions while the control logic remains manageable through location-based classification rather than complex individual control for each word line.
4Reliability
If different dummy voltages are applied to different dummy word lines based on location, then the reliability is improved, but the control logic becomes more complex
Solution Approach 1:
The patent changes the voltage parameter based on the location parameter of dummy word lines. By establishing a clear mapping relationship between word line locations and corresponding dummy voltages, the control logic uses simple parameter substitution rather than complex decision-making, thus improving reliability through parameter differentiation while keeping the control logic relatively simple through systematic parameter assignment.
Data Source
AI summary
A memory device includes a memory cell that is configured to have data stored therein, and a control logic that is configured to determine a dummy voltage based on a location of a selected word line electrically connected to the memory cell, and is configured to apply the dummy voltage to dummy word lines. First and second ones of the dummy word lines are adjacent to opposing ends in a vertical direction of a memory NAND string including the memory cell, respectively.