Flash Memory Wear Tracking via Erase Time Recording
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Solution Overview
Problem
Flash memory storage devices experience reliability issues and increased erase and programming times due to oxide traps and interface state generation at the drain junction during repeated cycling operations, leading to premature wear and performance degradation.
Innovation Solution
A flash memory storage device with a memory cell array and a memory control circuit that records erase times for each well region, allowing for the evaluation of device performance and enabling automatic tracking of erase operations to prevent overuse and maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated cycling operations (erase and programming) are performed on flash memory, then data storage functionality is maintained, but reliability decreases and oxide traps are generated in the tunnel oxide layer
Solution Approach 1:
The patent performs preliminary actions by recording erase times and interface state parameters before reliability degradation occurs. The system monitors and stores wear information during normal operation, enabling early detection and prevention of reliability issues before they manifest as actual failures.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring interface state and erase cycle counts, then using this information to evaluate memory block health and adjust operational parameters. The recorded data provides feedback on wear status, enabling dynamic management of memory reliability.
2Productivity
If repeated cycling operations are performed, then data storage capacity is utilized, but erase time and programming time increase slowing down operating speed
Solution Approach 1:
The patent performs preliminary classification and evaluation of memory block performance characteristics before they significantly degrade. By recording erase times and evaluating interface states early in the wear process, the system can proactively manage block allocation and prevent performance-critical operations on degrading blocks.
Solution Approach 2:
The system uses feedback from recorded erase times and interface state measurements to dynamically adjust operational strategies. This feedback enables the system to identify and isolate slowing blocks, redirecting operations to healthier blocks to maintain overall operating speed.
3Productivity
If repeated cycling operations are performed, then memory blocks are actively used, but premature wear occurs making bits fail to meet specifications
Solution Approach 1:
The patent implements preliminary monitoring and evaluation of memory block wear status by recording erase times and assessing interface states before bits fail to meet specifications. This early detection allows the system to retire or relocate data from approaching blocks, preventing specification failures.
Solution Approach 2:
The system uses feedback from wear monitoring data to make real-time decisions about block health and suitability for continued use. By continuously evaluating recorded parameters against threshold criteria, the system can proactively manage bit quality and prevent specification non-compliance.
4Measurement precision
If erase times of well regions are recorded and tracked, then device performance evaluation is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by having the memory system automatically record and evaluate its own wear characteristics during normal operation. The memory blocks themselves provide the data needed for their own health assessment through built-in monitoring of erase times and interface states, eliminating the need for external testing equipment.
Solution Approach 2:
The system creates simplified copies or representations of complex wear states by recording key parameters (erase times, interface state) that capture essential reliability information. These recorded data copies enable performance evaluation without requiring complex real-time analysis of the actual physical degradation processes.
Data Source
AI summary
A flash memory storage device including a memory cell array and a memory control circuit is provided. The memory cell array includes a plurality of well regions. Each of the well regions includes a plurality of memory blocks and a record block. The memory control circuit is coupled to the memory cell array. The memory control circuit is configured to perform an erase operation on the memory blocks of each of the well regions and record erase times of each of the well regions into the respective record block. In addition, a method for operating a flash memory storage device is also provided.