Memory Device Pass Voltage Segmentation for Program Reliability
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Solution Overview
Problem
Current memory devices face challenges in improving the reliability of program operations, particularly in managing pass voltages across unselected pages to prevent channel disconnection and reduce the program disturb phenomenon.
Innovation Solution
The memory device employs a method where different pass voltages are applied to word lines coupled to unselected pages based on whether a program operation has been performed, with specific voltage levels applied before and after a selected page reaches a reference page, to ensure stable program operations and prevent channel disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pass voltage is applied to all unselected pages, then the device complexity is reduced, but the reliability of program operation deteriorates due to channel disconnection and program disturb phenomenon
Solution Approach 1:
The patent segments unselected pages into two groups: those that have undergone program operations and those that have not. Different pass voltages are applied to each group, with higher voltages to programmed pages and lower voltages to unprogrammed pages. This segmentation resolves the contradiction by improving program operation reliability through differentiated voltage control while managing complexity through systematic classification.
Solution Approach 2:
The patent applies local quality by providing different pass voltage levels to different regions (groups of unselected pages) based on their program operation history. Pages that have undergone programming receive a first pass voltage, while pages that have not received a second pass voltage. This localized differentiation improves overall program reliability without requiring completely complex global control.
2Reliability
If higher pass voltage is applied to prevent channel disconnection, then the reliability improves, but the program disturb phenomenon increases
Solution Approach 1:
The patent applies different pass voltage levels to different groups of unselected pages based on whether they have undergone program operations. Pages that have been programmed receive higher pass voltages to maintain channel connection, while pages that have not been programmed receive lower pass voltages to avoid program disturb. This localized voltage differentiation resolves the contradiction by applying high voltage only where necessary for channel stability.
Solution Approach 2:
The patent segments unselected pages into two distinct groups with different voltage requirements. By separating programmed pages from unprogrammed pages and applying appropriate voltages to each segment, the system prevents channel disconnection in programmed pages while avoiding program disturb in unprogrammed pages.
Data Source
AI summary
Provided herein may be a memory device and a method of operating the same. The memory device may include a memory block including a plurality of pages, and peripheral circuits configured to sequentially program the pages. The memory device may include control logic configured to control the peripheral circuits such that a program voltage is applied to a word line coupled to a page selected from among the pages such that different pass voltages are applied to all or some word lines coupled to pages on which a program operation has been performed among unselected pages other than the selected page, and to word lines coupled to pages on which a program operation has not been performed among the unselected pages.