Dynamic Healing of NVM Tunnel Dielectric Charge Traps
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Solution Overview
Problem
Non-volatile memory (NVM) systems experience significant degradation in cycling performance and reliability due to charge trapping in tunnel dielectric layers over time, leading to decreased data retention and increased error rates after a large number of program/erase cycles.
Innovation Solution
The implementation of dynamic healing processes within NVM systems, which include applying drain stress and gate stress voltages during NVM operations to de-trap charges and repair damage to tunnel dielectric layers, thereby improving performance and extending the product lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If NVM cells undergo a large number of program/erase cycles, then storage capacity and operational flexibility are improved, but tunnel dielectric layers accumulate charge traps causing performance degradation
Solution Approach 1:
The patent applies preliminary healing actions by detecting performance degradation early through monitor cells and initiating healing processes before complete failure occurs. The system proactively applies stress voltages to remove trapped charges and restore tunnel dielectric properties, preventing catastrophic failure and extending the operational lifecycle of NVM cells through preventive maintenance rather than reactive repair
Solution Approach 2:
The patent implements self-service mechanisms where the NVM system automatically detects its own degradation through monitor cells and performs self-healing by applying appropriate stress voltages to remove trapped charges. This autonomous monitoring and self-repair capability allows the system to maintain reliability without external intervention, continuously restoring performance by activating healing circuits that reverse damage accumulation from cycling
2Reliability
If healing processes are applied frequently to maintain performance, then reliability is improved, but operational time and cycle efficiency are reduced
Solution Approach 1:
The patent employs feedback mechanisms by using monitor cells to continuously track tunnel dielectric health and triggering healing processes only when degradation thresholds are exceeded. This condition-based approach allows the system to maintain high reliability by applying healing actions precisely when needed rather than on fixed schedules, minimizing unnecessary operational interruptions while ensuring performance is restored before critical failure occurs
Solution Approach 2:
The patent applies partial healing actions by using monitor cells that represent only a portion of the total NVM capacity, healing only the affected segments rather than the entire memory array. This selective approach restores sufficient performance to meet reliability requirements while minimizing the time lost to healing operations, as the monitor cells provide adequate indication of overall system health without requiring comprehensive processing of all memory cells
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
Dynamic healing effectively reduces trapped charges, enhances cycling performance, and minimizes bit errors, maintaining reliability and performance levels by applying healing techniques contemporaneously with NVM operations, especially during elevated temperatures.
Implementation Method 1
relax damage within tunnel dielectric layers for NVM cells that occurs over time from charges (e.g., holes and/or electrons) becoming trapped within tunnel dielectric layers
Implementation Method 2
The healing process can be accelerated by elevated junction temperatures that occur during NVM cell operation
Data Source
AI summary
Methods and systems are disclosed for dynamic healing of non-volatile memory (NVM) cells within NVM systems. The dynamic healing embodiments described herein relax damage within tunnel dielectric layers for NVM cells that occurs over time from charges (e.g., holes and/or electrons) becoming trapped within these tunnel dielectric layers. NVM operations with respect to which dynamic healing processes can be applied include, for example, erase operations, program operations, and read operations. For example, dynamic healing can be applied where performance for the NVM system degrades beyond a selected performance level for an NVM operation, such as elevated erase/program pulse counts for erase/program operations and bit errors for read operations. A variety of healing techniques can be applied, such as drain stress processes, gate stress processes, and/or other desired healing techniques.