Floating Select Lines to Suppress GIDL Current in Memory Blocks
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Solution Overview
Problem
In semiconductor memory devices, the increased channel potential due to the gate-induced-drain-leakage (GIDL) current phenomenon during programming operations leads to inaccurate threshold voltage readings during read operations, as electrons are discharged but holes are trapped, causing channel potential increases in unselected memory blocks.
Innovation Solution
The semiconductor memory device includes a peripheral circuit that floats the source select lines and drain select lines of unselected memory blocks during programming, preventing channel potential increases and ensuring accurate data reading by suppressing GIDL current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If program operation is performed on selected memory blocks, then data is programmed successfully, but channel potential increases in unselected memory blocks due to GIDL current causing inaccurate threshold voltage readings
Solution Approach 1:
The patent applies preliminary anti-action by floating the select lines of unselected memory blocks before and during the program operation on selected blocks. This preemptive measure prevents GIDL current from generating harmful electron-hole pairs in unselected blocks, thereby preventing channel potential increases that would otherwise occur during programming operations.
Solution Approach 2:
The patent applies local quality by differentiating the treatment of select lines based on their memory block status. Selected memory blocks receive normal programming voltages while unselected memory blocks have their select lines floated. This localized differentiation ensures that only the necessary blocks undergo programming while protecting unselected blocks from GIDL current effects.
2Productivity
If program operation is performed on selected memory blocks, then data is programmed successfully, but holes are trapped in unselected memory block channels causing channel potential increases
Solution Approach 1:
The patent applies preliminary anti-action by floating the select lines of unselected memory blocks before program operations begin. This preemptive measure prevents GIDL current from generating harmful electron-hole pairs in unselected blocks, thereby preventing channel potential increases that would otherwise occur during programming operations.
Solution Approach 2:
The patent applies local quality by differentiating the treatment of select lines based on their memory block status. Selected memory blocks receive normal programming voltages while unselected memory blocks have their select lines floated. This localized differentiation ensures that only the necessary blocks undergo programming while protecting unselected blocks from GIDL current effects.
3Device complexity
If conventional programming is performed without floating select lines, then device complexity is low, but read accuracy deteriorates due to channel potential increases
Solution Approach 1:
The patent applies segmentation by dividing the memory device into selected and unselected memory blocks with distinct control strategies. The control circuit segments the select line control: floating select lines for unselected blocks and normal voltage control for selected blocks. This segmentation enables accurate threshold voltage measurement in unselected blocks while maintaining programming functionality in selected blocks.
Solution Approach 2:
The patent applies local quality by differentiating the treatment of select lines based on their memory block status. Selected memory blocks receive normal programming voltages while unselected memory blocks have their select lines floated. This localized differentiation ensures that only the necessary blocks undergo programming while protecting unselected blocks from GIDL current effects.
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 approach allows for accurate data reading after programming by maintaining stable channel potentials in unselected memory blocks, thereby improving the reliability of read operations.
Implementation Method 1
due to a bias condition applied to an unselected memory block, an electron-hole pair (EHP) by gate-induced-drain-leakage (GIDL) current phenomenon may be generated between a bit line and a drain select transistor and between a source line and a source select line
Data Source
AI summary
A semiconductor memory device and a method of operating the same are provided. The device may include a memory cell array including a plurality of memory blocks and a peripheral circuit configured for selecting one of the plurality of memory blocks and performing a program operation on selected memory cells of the selected memory block when the program operation is performed. The peripheral circuit may be configured to float a plurality of source select lines and a plurality of drain select lines of an unselected memory block of the plurality of memory blocks when the program operation is performed.