Memory Device Voltage Code Controller for Program Loop Reliability
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Solution Overview
Problem
Existing memory devices face challenges in reliably controlling pass voltages applied to unselected word lines during program operations, which can affect the accuracy and efficiency of data storage and retrieval.
Innovation Solution
A memory device and method that utilize a voltage code controller to generate and incrementally adjust program and pass voltages based on the number of program loops, with the pass voltages applied to unselected word lines increasing stepwise in proximity to the selected word line, enhancing the reliability of program operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pass voltages are applied to unselected word lines during program operation, then interference between selected and unselected memory cells is reduced, but channel voltage differences and hot electron generation increase
Solution Approach 1:
The patent applies dynamic voltage adjustment by sequentially increasing pass voltages in subsequent program loops based on proximity to the selected word line. Instead of using fixed pass voltages, the system dynamically adapts voltage levels across different loops and word lines, resolving the contradiction between reducing interference and preventing harmful effects like hot electron generation.
Solution Approach 2:
The patent implements localized voltage control by applying different pass voltage levels to different unselected word lines based on their proximity to the selected word line. Word lines closer to the selected line receive higher pass voltages in later loops, while distant lines receive lower voltages, thereby locally optimizing interference reduction without uniformly increasing harmful effects across all word lines.
2Manufacturing precision
If pass voltages are increased to improve program accuracy, then data storage precision improves, but device complexity and control difficulty increase
Solution Approach 1:
The patent segments the pass voltage control into multiple levels based on word line proximity groups. Instead of individually controlling each unselected word line, the system divides them into proximity-based groups and applies segmented voltage levels, thereby achieving precise local control while reducing overall control complexity through systematic grouping.
Solution Approach 2:
The patent performs preliminary classification of unselected word lines into proximity groups before the program operation begins. This pre-organization allows the system to systematically apply appropriate voltage levels in subsequent loops without real-time complex decision-making, reducing control complexity while maintaining precision.
Data Source
AI summary
Provided is a memory device. The memory device may include a voltage code controller configured to generate a voltage code that generates a program voltage and pass voltages based on a number of times a program loop is performed, and a voltage generator configured to generate the program voltage and the pass voltages in response to the voltage code, transmit the program voltage to a selected word line, and transmit the pass voltages to unselected word lines, wherein the voltage generator is configured to sequentially increase the pass voltage that is applied to the unselected word lines in order of proximity to the selected word line as the number of times a program loop is performed increases.