F. Saigne

SEL Hardness Assurance in a Mixed Radiation Field

This paper explores the relationship between monoenergetic and mixed-field Single Event Latchup (SEL) cross sections, concluding that for components with a very strong energy dependence and highly-energetic environments, test results from monoenergetic or soft mixed-field spectra can significantly underestimate the operational failure rate. We introduce a semi-empirical approach that can be used to evaluate the SEL rate for such environments based on monoenergetic measurements and information or assumptions on the respective sensitive volume and materials surrounding it. We show that the presence of high-Z materials such as tungsten is particularly important in determining the hadron cross section energy dependence for components with relatively large LET thresholds.

Proton-Induced SDRAM Cell Degradation

Retention time degradation and cell functionality under proton irradiation is studied for two SDRAM references that exhibit in-flight faulty behavior. Elements that may be used for physical interpretation of the phenomenon are given.

Heavy-Ion Radiation Impact on a 4 Mb FRAM Under Different Test Modes and Conditions

The impact of heavy-ions on commercial Ferroelectric Memories (FRAMs) is analyzed. The influence of dynamic and static test modes as well as several stimuli on the error rate of this memory is investigated. Static test results show that the memory is prone to temporary effects occurring in the peripheral circuitry, with a possible effect due to fluence. Dynamic tests results show a high sensitivity of this memory to switching activity of this peripheral circuitry.

Dose Rate Switching Technique on ELDRS-Free Bipolar Devices

The Switched Dose Rate technique is investigated when devices do not exhibit ELDRS. Experimental data and modeling results are presented and discussed in terms of hardness assurance. It is shown, for devices that do not show ELDRS, that a time is required before the switched devices reach the LDR curve. As a solution, it is proposed to apply an annealing between the HDR and the LDR irradiation.

Methodologies for the Statistical Analysis of Memory Response to Radiation

Methodologies are proposed for in-depth statistical analysis of Single Event Upset data. The motivation for using these methodologies is to obtain precise information on the intrinsic defects and weaknesses of the tested devices, and to gain insight on their failure mechanisms, at no additional cost. The case study is a 65 nm SRAM irradiated with neutrons, protons and heavy ions. This publication is an extended version of a previous study [1].

Investigation on MCU Clustering Methodologies for Cross-Section Estimation of RAMs

During irradiation testing of RAMs, various failure scenarios may occur which may generate different characteristic Multiple Cell Upset (MCU) error patterns. This work proposes a method based on spatial and temporal criteria to identify them.

Proton-Induced Single-Event Degradation in SDRAMs

Retention time and cell functionality degradation under proton irradiation is studied for SDRAM references that exhibit in-flight faulty behavior on satellites. Proton irradiation, with an adapted test protocol, allows to reproduce these effects and to gain a valuable insight on this phenomenon. Data acquired allow for a physical interpretation of the degradation, which results of one or more damage clusters created by a single particle.

SEE on Different Layers of Stacked-SRAMs

This paper presents heavy-ion and proton radiation test results of a 90 nm COTS SRAM with stacked structure. Radiation tests were made using high penetration heavy-ion cocktails at the HIF (Belgium) and at RADEF (Finland) as well as low energy protons at RADEF. The heavy-ion SEU cross-section showed an unusual profile with a peak at the lowest LET (heavy-ion with the highest penetration range). The discrepancy is due to the fact that the SRAM is constituted of two vertically stacked dice. The impact of proton testing on the response of both stacked dice is presented. The results are discussed and the SEU cross-sections of the upper and lower layers are compared. The impact of the stacked structure on the proton SEE rate is investigated.

The Power Law Shape of Heavy Ions Experimental Cross Section

Instead of using encapsulated sensitive volumes to simulate charge collection during single event upset (SEU) mechanism, we use continuous variation of the charge collection in the device. Basically, the collection efficiency is equal to 1 in the core of the sensitive volume and decreases outside. Assuming that the collection efficiency decreases as a power law of the distance, we analytically find that heavy ion SEU cross-section follows a power law of the linear energy transfer (LET). Results are in agreement with a set of various experimental data from 250nm to 28nm. We also show that experimental results allow extracting technological parameters of the sensitive volume as well as the threshold LET, which is a feature of the device.

TCAD simulations of leakage currents induced by SDRAM single-event cell degradation

We implemented the Gossick cluster damage in a TCAD simulation suite to identify the mechanism of retention time drop in irradiated SDRAM cell. The location of the cluster appears to be a key parameter. Simulations results are coherent with previous studies and explained by semiconductor physics.