Characterizing Single Particle Irradiation Threshold Voltage Fluctuations

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Solution Overview

Problem

Current integrated circuit designs fail to account for irradiation-induced fluctuations, leading to reliability issues and potential failures in microelectronic devices exposed to heavy ions, protons, and neutrons, as the effect of single particle irradiation on device characteristics is not adequately considered.

Innovation Solution

A method involving testing devices before and after single-particle irradiation to characterize threshold voltage fluctuations, using Pelgrom diagrams to calculate the irradiation-induced fluctuation, and incorporating this into a process fluctuation model to correct design margins and improve reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If single particle irradiation is not considered in circuit design, then design process is simple, but reliability of microelectronic devices under irradiation is degraded

Engineering Contradiction:

Improvereliability of microelectronic devices under irradiationVSAvoidcomplexity of design process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing single-particle irradiation tests on devices before final circuit design and characterization. By conducting irradiation experiments in advance and obtaining threshold voltage fluctuation data beforehand, the method enables correction of design margins during the design phase without requiring complex real-time irradiation monitoring, thus improving reliability while maintaining design process feasibility

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex physical irradiation testing of complete circuits with a simplified approach: testing individual devices to extract fluctuation parameters, then using statistical models to predict circuit-level effects. This substitution of direct mechanical/physical testing with modeling and calculation reduces the complexity of the overall design process while still accounting for irradiation effects

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If design margin is not corrected for irradiation-induced fluctuation, then design is straightforward, but circuits suffer degraded reliability

Engineering Contradiction:

Improveoperation reliability of circuitsVSAvoidprecision of design margin

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements feedback by using irradiation test results from fabricated devices to update and correct the design margin. The process forms a closed loop: design → fabricate → irradiate → measure fluctuation → correct design margin → redesign. This feedback mechanism ensures that design margins are precisely adjusted based on actual irradiation-induced fluctuations observed in the specific process node, thereby improving both reliability and precision of design margin

Inventive Principle:

Principle #23Feedback

3Measurement precision

If single particle irradiation effect is ignored, then device characterization is simple, but threshold voltage fluctuation under irradiation is not accounted for

Engineering Contradiction:

Improveaccuracy of threshold voltage characterizationVSAvoidcomplexity of testing process

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating the characterization process into distinct phases: pre-irradiation testing to establish baseline parameters, irradiation exposure phase, and post-irradiation testing to measure fluctuation. By segmenting the testing process and analyzing threshold voltage changes between phases, the method achieves precise measurement of irradiation-induced fluctuation without requiring overly complex simultaneous measurement systems

Inventive Principle:

Principle #1Segmentation

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 method effectively characterizes and corrects design margins for microelectronic devices, enhancing their reliability in irradiation environments by quantifying and mitigating the impact of single particle irradiation on threshold voltage fluctuations.

Implementation Method 1

charged particles will be ionized inside the device to generate a large number of electron-hole pairs, which are absorbed by the electrodes to form a single event transient current

Methodology Applied

Scientific EffectIonization: Ionisation

Implementation Method 2

the electron-hole pairs generated from the ionization of the charged particles may be captured by traps in the oxide layer to produce micro-dose effect

Methodology Applied

Scientific EffectCharge trapping: Absorption (physical)

Data Source

PatentUS11525857B2Method for characterizing fluctuation induced by single particle irradiation in a device and application thereof

Publication Date: 2022.12.13 PEKING UNIV

AI summary

A method for characterizing a fluctuation induced by single particle irradiation in a device. A plurality of devices varying in size are tested respectively before and after irradiation to obtain threshold voltage distribution, such that a threshold voltage fluctuation induced by irradiation is obtained and used to correct a process fluctuation model, so as to correct a design margin of the devices working under the irradiation.