Memory Block Detrap Heating for Retention Recovery
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Solution Overview
Problem
Existing memory devices face challenges in maintaining retention characteristics of memory cells due to program/erase cycles, leading to reliability issues.
Innovation Solution
A memory device with a control logic that counts program/erase operations and performs a detrap operation by applying a heating current to the channel of memory blocks when the program/erase count exceeds a set number, liberating trapped electrons to improve retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If program/erase operations are performed repeatedly on memory blocks, then data storage capacity and operation count increase, but retention characteristics of memory cells deteriorate
Solution Approach 1:
The patent performs a detrap operation as a preliminary action before the retention characteristic deteriorates completely. When the program/erase count reaches a predetermined threshold, the system proactively applies a heating current to the channel to release trapped electrons, preventing further degradation of retention characteristics and preparing the memory block for continued reliable operation.
Solution Approach 2:
The patent converts the harmful effect of trapped electrons (which cause retention deterioration) into a manageable condition by detecting the program/erase count and actively releasing the trapped electrons through controlled heating. The trapping phenomenon, which initially causes harm, becomes a detectable signal that triggers a corrective action, transforming the problem into a controlled maintenance process.
2Reliability
If a detrap operation is performed to release trapped electrons, then retention characteristic improves, but additional current and time resources are consumed
Solution Approach 1:
Instead of continuously applying heating current or performing detrap operations, the patent implements periodic action by triggering the detrap operation only when the program/erase count reaches a predetermined threshold. This conditional, periodic approach maintains retention characteristics while minimizing unnecessary current consumption and operation time.
Solution Approach 2:
The patent changes the operational parameters dynamically based on the program/erase count. The heating current is applied only when the count exceeds a threshold value, and the current magnitude and application duration are optimized for the detrap purpose. This parameter-based control ensures energy efficiency by applying power only when and where needed.
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
The detrap operation enhances the reliability of memory blocks by releasing trapped electrons, thereby improving the retention characteristics and overall performance of the memory device.
Implementation Method 1
the peripheral circuit applies a heating current to a channel of each of the plurality of strings included in the selected memory block in the detrap operation
Data Source
AI summary
A memory device performs a detrap operation on a selected memory block when the number of program/erase cycles of the selected memory block equals or exceeds a predetermined set number. A circuit included in the memory device applies a heating current to a heating layer, thermally coupled to the channel of each of the plurality of strings included in the selected memory block in the detrap operation.