Nonvolatile Memory Device ISPP Voltage Control
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Solution Overview
Problem
Conventional nonvolatile memory devices face challenges in maintaining an adequate pass voltage window, leading to potential over-programming and fail conditions due to disturbances in program and pass voltages, which affects the reliability and data storage density.
Innovation Solution
The implementation of a nonvolatile memory device with a high-voltage generator and control logic that iteratively increases the program voltage pulse and adjusts pass voltages, using Incremental Step Pulse Program (ISPP) to maintain an increased program voltage and optimize the pass voltage window, while controlling parasitic capacitance effects to prevent over-programming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional nonvolatile memory devices use fixed program voltage and pass voltage, then the device structure is simple, but the pass voltage window is insufficient leading to over-programming and reliability issues
Solution Approach 1:
The patent applies dynamics by transitioning from fixed voltage levels to dynamic, iterative voltage adjustment. The control logic iteratively increases the program voltage pulse level and adjusts pass voltage levels during the programming operation, allowing the system to adapt to changing electrical conditions and maintain an adequate pass voltage window throughout the programming process, thereby preventing over-programming while managing device complexity through controlled automation.
Solution Approach 2:
The patent implements parameter changes by systematically varying the program voltage and pass voltage parameters during the programming operation. The control logic modifies voltage levels iteratively, increasing program voltage pulse levels and adjusting pass voltage according to defined increments and conditions, enabling the system to optimize the pass voltage window and prevent over-programming through controlled parameter evolution.
2Productivity
If the program voltage is increased to improve programming efficiency, then programming speed increases, but the pass voltage window narrows increasing the risk of over-programming
Solution Approach 1:
The patent applies feedback by implementing iterative control where the control logic monitors the programming process and adjusts voltage levels accordingly. The control logic iteratively increases the program voltage pulse and adjusts pass voltage levels based on the programming state, effectively managing the balance between programming efficiency and preventing over-programming through continuous feedback and adaptive voltage adjustment.
Solution Approach 2:
The patent implements periodic action through iterative voltage adjustment cycles. The control logic performs repeated cycles of increasing program voltage pulse levels and adjusting pass voltage in defined increments, creating a structured sequence of voltage applications that systematically progresses through programming stages while maintaining control over the pass voltage window to prevent over-programming.
3Reliability
If the pass voltage is increased to prevent over-programming, then the pass voltage window improves, but the program voltage must be increased further to maintain programming effectiveness
Solution Approach 1:
The patent applies dynamics by implementing dynamic voltage adjustment where both program voltage and pass voltage are iteratively modified during the programming operation. The control logic adjusts pass voltage levels in response to programming conditions and simultaneously manages program voltage pulse levels, creating a coordinated dynamic voltage control strategy that optimizes the pass voltage window while managing the energy required for effective programming.
Data Source
AI summary
A nonvolatile memory device includes; a memory cell array including a plurality of memory cells arranged in word lines and bit lines, a high-voltage generator generating a program voltage pulse applied to a selected word line among the word lines, and a pass voltage applied to a non-selected word line, and control logic iteratively increasing the program voltage pulse and adjusting the pass voltage according to a defined increment during a program operation.