Nonvolatile Memory Flag Page Buffer Selection
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Solution Overview
Problem
The proximity effect in nonvolatile memory devices, such as NAND type flash memory, leads to changes in threshold values between adjacent memory cells, making it difficult to increase storage capacity and maintain data integrity due to inter-cell interference.
Innovation Solution
A nonvolatile memory device configuration that includes flag page buffers and a data input/output control unit to selectively enable and disable flag page buffers, ensuring that no adjacent flag page buffers are simultaneously enabled, thereby minimizing interference between memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the level of integration for memory cells is increased to increase storage capacity, then storage capacity is improved, but proximity effect causes threshold value changes in adjacent cells, worsening data integrity
Solution Approach 1:
The memory device is divided into multiple pages, each with its own dedicated flag page buffer. This segmentation isolates the control signals for different memory regions, preventing interference between adjacent cells across page boundaries while maintaining high integration levels.
Solution Approach 2:
A data input/output control unit is introduced as an intermediary between the flag page buffers and the memory cells. This control unit selectively enables or disables specific flag page buffers based on the current operation, preventing simultaneous activation of adjacent buffers and thereby reducing proximity effects.
2Productivity
If multiple flag page buffers are simultaneously enabled to increase data input/output capability, then productivity is improved, but adjacent buffers cause inter-cell interference, worsening threshold value distribution control
Solution Approach 1:
The flag page buffers are dynamically enabled or disabled based on the current data input/output operation. The data input/output control unit selectively activates only the necessary buffers, allowing flexible configuration of active buffers to avoid adjacency and prevent interference while maintaining high productivity.
Solution Approach 2:
Instead of enabling all flag page buffers simultaneously, the system enables only the necessary number of buffers (R buffers) for the current operation. This partial action reduces the total number of active buffers, minimizing inter-cell interference while still providing sufficient data input/output capability.
Data Source
AI summary
A nonvolatile memory device includes: N (N is an integer equal to or greater than 2) number of nonvolatile memory cells disposed in a flag area of a page, N number of flag page buffers configured to input and output flag data to and from the nonvolatile memory cells of the flag area, and a data input/output control unit configured to select R number of flag page buffers so that the flag data is inputted and outputted from the R selected flag page buffers and no flag data is inputted and outputted through unselected N-R number of flag page buffers, wherein no one flag page buffer of the R selected flag page buffers is immediately adjacent to another one of the R selected flag page buffers.