Nonvolatile Memory Device Floating Common Source Line
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Solution Overview
Problem
In nonvolatile memory devices, the coupling between the common source line (CSL) and bitlines during programming operations reduces the incremental step pulse programming (ISPP) effect, leading to decreased program speed and increased power consumption.
Innovation Solution
The CSL is set up to a predetermined voltage and then floated during the program operation to minimize coupling with bitlines, thereby improving program speed and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common source line is maintained at a fixed voltage during programming operations, then the memory device can maintain stable operation, but the coupling between the common source line and bitlines reduces the incremental step pulse programming effect, leading to decreased program speed and increased power consumption
Solution Approach 1:
The common source line voltage is dynamically adjusted between different states (fixed voltage during setup, floating during programming) based on the operational phase, allowing the system to optimize both stability during configuration and programming speed during data writing operations
2Reliability
If the common source line is maintained at a fixed voltage during programming operations, then the memory device can maintain stable operation, but the coupling between the common source line and bitlines increases power consumption
Solution Approach 1:
The common source line voltage is dynamically switched between fixed and floating states according to the programming phase, reducing unnecessary power consumption during programming operations while maintaining stability during setup phases
3Productivity
If the common source line is floated during programming operations, then the incremental step pulse programming effect is maintained improving program speed, but the common source line requires additional control mechanisms
Solution Approach 1:
The common source line is pre-configured to float automatically during programming operations through the control logic, eliminating the need for complex real-time adjustments while maintaining the improved programming speed
Data Source
AI summary
A programming method is for programming a nonvolatile memory device including a plurality of strings disposed perpendicular to a substrate and connected between bitlines and a common source line. The programming method includes setting up the common source line to a predetermined voltage, floating the setup common source line, performing a program operation on memory cells connected to a selected wordline, and performing a verify operation on the memory cells.