Abstract-Recently, the occurrence of multiple events in static tests has been investigated by checking the statistical distribution of the difference between the addresses of the words containing bitflips. That method has been successfully applied to Field Programmable Gate Arrays (FPGAs) and the original authors indicate that it is also valid for SRAMs. This paper presents a modified methodology that is based on checking the XORed addresses with bitflips, rather than on the difference. Irradiation tests on CMOS 130 & 90 nm SRAMs with 14-MeV neutrons have been performed to validate this methodology. Results in high-altitude environments are also presented and cross-checked with theoretical predictions. In addition, this methodology has also been used to detect modifications in the organization of said memories. Theoretical predictions have been validated with actual data provided by the manufacturer.

No abstract

After having carried out radiation experiments on memories, the detected bitflips must be classified into single bit upsets and multiple events to calculate the cross sections of different phenomena. There are some accepted procedures to determine if two bitflips are related. However, if there are enough bitflips, it is possible that unrelated pairs of errors appear in nearby cells and they are erroneously taken as a multiple event. In this paper, radiation experiments are studied as a special case of the urn-and-balls problem in probability theory to estimate how the measured multiple-event cross sections must be corrected to remove the overestimation due to the false events.

Abstract-This paper presents the characterization of the sensitivity to 14-MeV neutrons of a Commercial Off-The-Shelf (COTS) 90-nm Static Random Access Memories (SRAMs) manufactured by Cypress Semiconductor, when biased at ultra low voltage. Firstly, experiments exposing this memory at 14-MeV neutrons, when powering it up at bias voltages ranging from 0.5V to 3.3V, are presented and discussed. These results are in good concordance with theoretical predictions issued by the modeling tool MUSCA-SEP 3 (MUlti-SCAles Single Event Phenomena Predictive Platform). Then, this tool has been used to obtain Soft Error Rate (SER) predictions at different altitudes above the Earth's surface of this device vs. its bias voltage. Finally, the effect of contamination by α particles has also been estimated at said range of bias voltages.

Abstract-This paper presents a SEU sensitivity characterization at ultra-low bias voltage of three generations of COTS SRAMs manufactured in 130 nm, 90 nm and 65 nm CMOS processes. For this purpose, radiation tests with 14.2 MeV neutrons were performed for SRAM power supplies ranging from 0.5 V to 3.15 V. The experimental results yielded clear evidences of the SEU sensitivity increase at very low bias voltages. These results have been cross-checked with predictions issued from the modeling tool MUlti-SCAles Single Event Phenomena Predictive Platform (MUSCA-SEP 3 ). Large-scale SELs and SEFIs, observed in the 90-nm and 130-nm SRAMs respectively, are also presented and discussed.