Semiconductor Memory Device Page Buffer Sensing Signal Adjustment
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Solution Overview
Problem
Semiconductor memory devices with nonvolatile memory cells face challenges in efficiently performing sensing operations due to variations in channel lengths of memory strings, which affect cell current values and operational accuracy.
Innovation Solution
The semiconductor memory device incorporates a memory cell array with first and second memory strings of different channel lengths, utilizing a page buffer group and control logic to generate adjusted page buffer sensing signals, allowing for accurate sensing operations by distinguishing between channel lengths through voltage level adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory strings with different channel lengths are used to increase storage capacity, then storage capacity is improved, but sensing accuracy deteriorates due to cell current variations
Solution Approach 1:
The patent applies local quality by providing different voltage levels to page buffer sensing signals based on the specific channel length of selected memory strings. Memory strings are divided into groups (first group with longer channel length, second group with shorter channel length), and each group receives appropriately adjusted sensing signal voltage levels to compensate for channel length variations and achieve uniform cell current for accurate sensing
Solution Approach 2:
The patent changes the voltage level parameter of page buffer sensing signals based on the channel length of selected memory strings. The control logic adjusts the voltage level of sensing signals dynamically - using a first voltage level for memory strings in the first group and a second voltage level for memory strings in the second group - to compensate for channel length differences and maintain consistent sensing accuracy
2Device complexity
If a single page buffer sensing signal voltage level is used for all memory strings, then device complexity is reduced, but sensing accuracy deteriorates due to channel length variations
Solution Approach 1:
The patent implements dynamic signal control where the voltage level of page buffer sensing signals is adjusted in real-time based on which memory string group is being accessed. The control logic dynamically selects between a first voltage level and a second voltage level depending on the channel length of the selected memory strings, allowing accurate sensing without requiring complex hardware modifications
Data Source
AI summary
Disclosed are a semiconductor memory device and an operating method thereof. The semiconductor memory device may include a memory cell array, a page buffer group, and a control logic. The memory cell array may include a first memory string and a second memory string, which have different channel lengths. The page buffer group may perform a sensing operation on the memory cell array in response to a page buffer sensing signal. The control logic may control the page buffer group to perform the sensing operation, and, during the sensing operation and output the adjusted page buffer sensing signal, may adjust a voltage level of the page buffer sensing signal according to a selected memory string.