3D Flash Memory Radiation Sensing for Tiered Error Mitigation

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Solution Overview

Problem

Flash memory is vulnerable to ionizing radiation, leading to data errors and limiting its use in high-radiation environments without effective and cost-efficient shielding solutions.

Innovation Solution

Implementing a memory controller that senses radiation exposure and performs data refresh operations, adjusts read voltage, and conducts fault repair to mitigate radiation-induced charge leakage, along with varying error correction code (ECC) strength based on radiation susceptibility of 3D memory cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If shielding is used to reduce radiation exposure, then radiation tolerance is improved, but cost and device size increase

Engineering Contradiction:

Improveradiation toleranceVSAvoidshielding structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the harmful effect of radiation into a useful signal by using radiation-induced charge leakage as a measurable indicator. The system intentionally allows controlled charge leakage through the oxide-semiconductor layer and uses this leakage to trigger data refresh operations, thereby transforming radiation from a purely destructive force into a detectable event that initiates protective actions.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where radiation-induced charge leakage is continuously monitored through voltage threshold detection. When the leakage exceeds a predetermined threshold, the system automatically triggers a data refresh operation to correct errors. This closed-loop feedback system enables dynamic adaptation to radiation conditions without requiring bulky passive shielding.

Inventive Principle:

Principle #23Feedback

2Reliability

If data refresh operations are performed frequently, then data integrity is improved, but memory degradation and energy consumption increase

Engineering Contradiction:

Improvedata integrityVSAvoidmemory lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent makes the data refresh operation dynamic by adjusting its frequency based on actual radiation conditions. Instead of periodic refreshes at fixed intervals, the system performs refresh operations only when radiation-induced charge leakage exceeds a predetermined threshold. This dynamic approach optimizes the balance between maintaining data integrity and preserving memory lifespan by avoiding unnecessary refresh operations during low-radiation periods.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If uniform ECC strength is applied to all memory cells, then implementation simplicity is maintained, but radiation susceptibility varies across different cell locations

Engineering Contradiction:

ImproveECC implementationVSAvoidradiation susceptibility

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by varying the ECC strength according to the specific radiation susceptibility of different memory cell locations. Memory cells are divided into groups with different ECC configurations based on their position within the 3D structure, where cells more exposed to radiation receive stronger error correction. This localized approach optimizes radiation tolerance for each region without uniformly increasing complexity across the entire memory system.

Inventive Principle:

Principle #3Local quality

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

Enhances radiation tolerance of flash memory by maintaining data integrity and reducing errors over extended periods, while minimizing memory degradation and cost.

Implementation Method 1

Each cell is typically defined by an oxide-semiconductor layer that allows ions to tunnel through it based on applied voltage in order to change the amount of charge in a floating gate of the cell

Methodology Applied

Scientific EffectTunneling:

Implementation Method 2

Ionizing radiation can change the conductivity of the oxide-semiconductor layers such that a significant amount of charge may leak out of the cells thereby causing errors in the stored data

Methodology Applied

Scientific EffectIonizing radiation: Radiation

Data Source

PatentUS12592295B1Systems and methods for improving radiation tolerance of three- dimensional flash memory

Publication Date: 2026.03.31 UNIVERSITY OF ALABAMA

AI summary

A system for improving radiation tolerance of memory senses an amount of radiation exposure and, based on the sensed amount of radiation exposure, determines whether to perform one or more techniques for mitigating the effects of the radiation exposure. As an example, the system may perform a data refresh operation by re-writing data that has been corrupted by radiation, or the system may adjust the reference voltage used to read memory cells. In another example, the system may perform a fault repair operation by re-programming cells that have erroneously transitioned from a program state to an erase state. The system may selectively perform different radiation-mitigation techniques in a tiered approach based on the sensed amount of radiation in order to limit the adverse effects of the more invasive techniques.