Nonvolatile Memory Word Line Current Control
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Solution Overview
Problem
There is a need to increase the reliability of memory cells in three-dimensional nonvolatile memory devices as they face challenges in maintaining performance and efficiency due to process variations and structural complexities.
Innovation Solution
A nonvolatile memory device design that includes a memory cell array with a substrate and vertical conductive materials, where the word line current is adjusted based on the distance from the substrate and the cross-sectional area of the bit lines, allowing for precise control over the set and reset operations through a variable current supply block and control logic block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If memory cells are arranged in a three-dimensional structure to increase integration and capacity, then the degree of integration and capacity increase, but process variations and structural complexities increase, leading to decreased reliability
Solution Approach 1:
The patent applies local quality by adjusting the word line current based on the specific distance of each memory cell group from the substrate. Different current amounts are supplied to different regions (first group vs. second group) depending on their distance from the substrate, optimizing performance for each local region while maintaining overall reliability in the three-dimensional structure
Solution Approach 2:
The patent changes the electrical parameter (word line current amount) based on the spatial parameter (distance from substrate). The control logic block adjusts the current parameter dynamically according to which group of memory cells is selected, compensating for process variations through parameter modulation rather than structural modification
2Device complexity
If uniform word line current is supplied to all memory cells, then the device complexity is reduced, but performance consistency across different distances from the substrate deteriorates
Solution Approach 1:
The patent implements dynamics by making the word line current supply adaptive rather than static. The variable current supply block and control logic block dynamically adjust the current amount based on real-time selection of memory cell groups at different distances from the substrate, enabling the system to respond to operational requirements without increasing fundamental structural complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the reliability of memory cells in three-dimensional structures by optimizing the word line current distribution, ensuring effective set and reset operations and maintaining performance across varying conditions.
Implementation Method 1
a variable current supply block configured to generate a word line current to be supplied to a word line selected from the first group of word lines or the second group of word lines
Data Source
AI summary
A nonvolatile memory device includes a memory cell array, a word line drive block that is connected to a first group of memory cells through a first group of word lines and to a second group of memory cells through a second group of word lines, a bit line bias and sense block that is connected to the first and second groups of memory cells through bit lines, a variable current supply block that generates a word line current to be supplied to a selected word line, and a control logic block that receives an address and a command and controls the variable current supply block to adjust an amount of the word line current based on the address. The control logic block further varies the amount of the word line current depending on a distance between the selected word line and the substrate.