Memory Device Channel Negative Boosting Mitigation
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Solution Overview
Problem
Existing memory devices face challenges in preventing or mitigating the channel negative boosting phenomenon during sensing operations, which can lead to data reliability issues due to threshold voltage distribution shifts and read disturb phenomena.
Innovation Solution
The memory device employs a control logic system that manages voltages applied to drain select lines, source select lines, and word lines, including a method to set different voltages for unselected drain select lines based on whether they share a cell string with the selected drain select line, and applies a voltage to a dummy line to control channel potential, thereby preventing or mitigating channel negative boosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage control is used during sensing operation, then the sensing operation can be performed, but channel negative boosting phenomenon occurs causing threshold voltage distribution shifts and read disturb
Solution Approach 1:
The patent applies different voltage levels to different drain select lines based on their specific connection characteristics. Specifically, a first voltage level is applied to a first drain select line while a second voltage level (different from the first) is applied to a second drain select line. This local differentiation prevents channel negative boosting in specific regions without affecting the entire memory block uniformly, thereby maintaining data reliability while mitigating the harmful phenomenon.
Solution Approach 2:
The patent changes the voltage parameter applied to drain select lines during the sensing operation. By adjusting the voltage level on unselected drain select lines to be different from the selected drain select line, the patent modifies the electrical conditions to prevent channel negative boosting. This parameter change approach allows the sensing operation to proceed while avoiding threshold voltage distribution shifts and read disturb effects.
2Device complexity
If voltage is applied to all drain select lines uniformly, then the memory structure is simple to control, but cell strings are shared causing channel negative boosting
Solution Approach 1:
The patent implements local quality by applying different voltage levels to different drain select lines based on whether they share cell strings with the selected drain select line. This creates a differentiated voltage control scheme where specific lines receive specific voltages based on their functional relationships, preventing channel negative boosting in shared cell strings while maintaining manageable control complexity through systematic voltage assignment.
Data Source
AI summary
The present technology relates to an electronic device. A memory device that controls a voltage applied to each line to prevent or mitigate a channel negative boosting phenomenon during a sensing operation includes a memory block connected to a plurality of lines, a peripheral circuit configured to perform a sensing operation on selected memory cells connected to a selected word line among the plurality of lines, and control logic configured to control voltages applied to drain select lines, source select lines, and word lines between the drain select lines and the source select lines among the plurality of lines, during the sensing operation and an equalizing operation performed after the sensing operation. The control logic controls a voltage applied to an unselected drain select line according to whether a cell string is shared with a selected drain select line among the drain select lines, during the sensing operation.