Single Event Upset Measurements Research Articles

Analysis of the Radiation Field Generated by 200-MeV Electrons on a Target at the CLEAR Accelerator at CERN

The radiation showers generated by the interaction of high-energy electrons with matter include neutrons with an energy distribution peaked at the MeV scale, produced via photonuclear reactions, allowing measurements of neutron-induced Single-Event Effects in electronic devices. In this work we study a setup where the 200-MeV electron beam of the CLEAR accelerator at CERN is directed on an aluminum target to produce a radiation field with a large neutron component. The resulting environment is analyzed by measuring the Single-Event Upset (SEU) and Latchup rates in well-characterized SRAMs, as well as the Total Ionizing Dose in passive Radio-Photo-Luminescence dosimeters, and by comparing the results with predictions from FLUKA simulations. We find that a lateral shielding made of lead protects the SRAMs from an excessive TID rate, yielding an optimal configuration for SEU measurements, particularly in SRAMs that are highly sensitive to MeV-scale neutrons. This setup provides an interesting complementary neutron source with respect to standard neutron facilities based on spallation targets or radioactive sources.

Analysis of the Photoneutron Field Near the THz Dump of the CLEAR Accelerator at CERN With SEU Measurements and Simulations

We study the radiation environment near the terahertz (THz) dump of the CERN Linear Electron Accelerator for Research (CLEAR) electron accelerator at CERN, using FLUktuierende KAskade in German (FLUKA) simulations and single-event upset (SEU) measurements taken with 32-Mbit Integrated Silicon Solution Inc. (ISSI) static random access memories (SRAMs). The main focus is on the characterization of the neutron field to evaluate its suitability for radiation tests of electronics in comparison with other irradiation facilities. Neutrons at CLEAR are produced via photonuclear reactions, mostly initiated by photons from the electromagnetic cascades that occur when the beam is absorbed by the dump structure. Good agreement is generally found between the measured single-event upset (SEU) rates and the expected values obtained from FLUKA simulations and the known SEU response of the ISSI SRAMs to neutrons, while one position is found to be potentially affected by photon-driven SEUs.

Analysis of SRAM-Based FPGA SEU Sensitivity to Combined EMI and TID-Imprinted Effects

This work proposes a novel methodology to evaluate SRAM-based FPGA’s susceptibility with respect to Single-Event Upset (SEU) as a function of noise on VDD power pins, Total-Ionizing Dose (TID) and TID-imprinted effect on BlockRAM cells. The proposed procedure is demonstrated for SEU measurements on a Xilinx Spartan 3E FPGA operating in an 8 MV Pelletron accelerator for the SEU test with heavy-ions, whereas TID was deposited by means of a Shimadzu XRD-7000 X-ray diffractometer. In order to observe the TID-induced imprint effect inside the BlockRAM cells, a second SEU test with neutrons was performed with Americium/Beryllium ( $^{241}{\hbox {AmBe}}$ ). The noise was injected into the power supply bus according to the IEC 61.000-4-29 standard and consisted of voltage dips with 16.67% and 25% of the FPGA’s VDD at frequencies of 10 Hz and 5 kHz, respectively. At the end of the experiment, the combined SEU failure rate, given in error/bit.day, is calculated for the FPGA’s BlockRAM cells. The combined failure rate is defined as the average SEU failure rate computed before and after exposition of the FPGA to the TID.

Investigation of Threshold Ion Range for Accurate Single Event Upset Measurements in Both SOI and Bulk Technologies

Experimental evidences are presented showing obvious differences in threshold ion range for silicon-on-insulator (SOI) and bulk static random access memories (SRAMs). Single event upset (SEU) cross sections of SOI SRAMs start to decline off the Weibull curve at ion ranges of 20.7 μm to 40.6 μm, depending on the ion species and also the thickness of metallization layers. Whereas for the bulk SRAMs, threshold range of Bismuth beam is unexpectedly larger than 60.4 μm. Underlying mechanisms are further revealed by Monte Carlo simulations and in-depth analysis. The relative location of ion's Bragg peak to the sensitive region and also the position of ion LET in the σ-LET curve of test device turn out to be two key parameters in determining the threshold ion range which can explain the experimental results. Significant discrepancies are observed in the deposited energy spectrums in sensitive regions of bulk SRAM by ions at different sides of the Bragg peak, but with almost the same LET at die surface (all with ion range larger than 30 μm). Energy straggling of incident ions at the die surface is considered by Monte Carlo calculations. Implications for hardness assurance testing are also discussed. A formula is proposed for calculating the “worst case” threshold ion range.

SEU Measurements and Simulations in a Mixed Field Environment

Single Event Upset (SEU) measurements were performed using the European Space Agency's (ESA) Standard SEU Monitor in the H4 Irradiation mixed-field test area at CERN. The results, tightly correlated with the radiation environment, are compared with those obtained with the CERN Radiation Monitors (RadMons) as well as with the Monte Carlo simulation of the experimental setup using the FLUKA Monte Carlo transport code. In addition, the SEU cross section of the device for particles and energies not available in standard testing (such as charged pions or GeV-energy hadrons) are simulated and discussed, showing an increase of over a factor 2 for nucleons in the 200 MeV-3 GeV range. A monoenergetic SEU cross section measurement at 120 GeV is included in the analysis.

Charge-Collection and Single-Event Upset Measurements at the ISIS Neutron Source

Charge-collection measurements at the VESUVIO instrument at ISIS are described. Neutron SEU cross sections in SRAM-based FPGAs are measured. Results are compared to equivalent data from Los Alamos Neutron Science Center ICE House. The rate of single-event effects due to fast neutrons at VESUVIO is approximately 15% of that at LANSCE. In addition there is a strong thermal and epithermal component, sufficient to cause many events in devices containing small amounts of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B. The effects of low-energy neutrons on a commercial CCD contaminated with traces of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sup> B are described. Cadmium shielding is found to be incompletely effective in separating the effects of fast and slow neutrons, and the implications for testing protocols and instrument design are discussed.

Single Event Upset Measurements of Memory Chips for the Langmuir Probe on STSAT-2

Single Event Upset Measurements of Memory Chips for the Langmuir Probe on STSAT-2 Kwangsun Ryu, Goo-Hwan Shin, Hyung-Myung Kim and Heejoon Kim Satellite Technology Research Center, Korea Advanced Institute of Science and Technology, Daejeon 305-701 Kyungwook Min Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Received 21 September 2007) We have measured the single event e ect (SEE) of candidate memory chips for a Langmuir probe, one of the secondary payloads of STSAT-2 (Science and Technology Satellite-2). The measurements were performed using the cyclotron proton accelerator at Korea Institute of Radiological and Medical Sciences. An ion chamber detector was used for the calibration of the ux of the proton beam. SEU (single event upset) cross-sections for 3 di erent kinds of memory chips were derived according to the incident proton energy. The SEU rate at the STSAT-2 orbit environment was estimated from the SEU cross-section and the modeled particle ux. The program memory chip for the ight model was selected from the candidates. PACS numbers: 61.80.Az, 61.82.Fk, 95.40.+s

SEU measurements and predictions on MPTB for a large energetic solar particle event

Single-event upset (SEU) ground testing and rate calculations have been performed for 16-Mb DRAMs flown on the microelectronics and photonics testbed experiment (MPTB) using measured particle spectra and compared with space data from a period of high solar activity. The results show that with the measured spectra, the measurements agree quite well with the calculations. Using just modeled environments, the results do not agree as well.

Scattering extraction of ions at CRYRING for SEU testing

A measuring station has been built at the CRYRING heavy ion accelerator to test the Single Event Upset (SEU) phenomena in working Static RAM circuits. The setup extracts the beam using Rutherford scattering and the ions are monitored with a BaF2 scintillator. SEU measurements have been performed for standard bulk CMOS memory circuits.

Monitoring SEU parameters at reduced bias (CMOS SRAM)

SEU (single event upset) sensitivity of a CMOS SRAM (static random-access memory) increases with decreasing bias in such a manner that the critical charge exhibits a linear dependence on bias. This should allow proton and neutron monitoring of SEU parameters even for radiation-hardened devices. The sensitivity of SEU rates to the thickness of the sensitive volume is demonstrated, and procedures for determining the SEU parameters using protons are outlined. A method for determining the thickness of the sensitive volume using SEU measurements at normal and grazing incidence has been developed. Values determined by this procedure agree with values obtained with large collection measurements, SEM measurements, and estimates from the thickness of the epi-layer.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The shape of heavy ion upset cross section curves (SRAMs)

An expression for SEU (single event upset) cross section for a unidirectional, monoenergetic ion beam is developed. The expression incorporates both the stochastics of the energy deposition process and the variability of the response of an array of memory cells. The energy deposition stochastics result from the distribution of path lengths the ion may take through a memory cell and the statistics of the charge production process. The variability in the memory response results from the dependence of the sensitive volume size on deposited charge and cell-to-cell variations due to processing. Thus the shape of a measured upset cross section curve is the result of the complex interplay of a number of physical processes whose relative contributions vary with experimental conditions, memory technology, and processing. A procedure for the separation of the basic memory response from the stochastics of the energy deposition process using heavy ion SEU measurements is given. This can be used to predict the SEU vulnerability in any radiation environment. Results of the model applied to data for bipolar and CMOS/SOS SRAMs (static random-access memories) are presented. >

Variation in SEU sensitivity of dose-imprinted CMOS SRAMs

The authors report on an experimental study of dose-induced changes in SEU (single-event-upset) sensitivity of CMOS static RAMs. Two time regimes were investigated following exposure of memories to cobalt-60 gamma rays: the near term, within a few hours after exposure, and the long term, after many days. Samples were irradiated both at room and at liquid nitrogen temperatures. The latter procedure was used in order to freeze in the damage state until SEU measurements could be made prior to annealing. Results show that memories damaged by dose are more sensitive to upsets by heavy ions. The induced changes are substantial: threshold linear energy transfer (LET) values decreased by as much as 46% and asymptotic cross sections increased by factors of 2 to 4 (unannealed samples).< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

SEU measurements on HFETs and HFET SRAMs

The single-event-upset (SEU) response of n/sup +/-AlGaAs/GaAs heterostructure field-effect transistors (HFETs) and HFET static random access memories (SRAMs) was evaluated by measuring their response to focused-electron-beam pulses. Initially the pulses were used to measure and model HFET drain and gate SEU responses. Circuit simulations using these SEU models predicted that an HFT memory is most vulnerable to a single-particle event in the area between the drain and the source (drain hit) of the OFF pull-down HFET. Subsequent testing of an HFET SRAM cell confirmed the above prediction. These SEU evaluations of HFETs and HFET memories show that measurements on individual HFETs and circuit simulations of SEU hits can be used to predict the SEU response of HFET memories. >

Charge collection in HI/sup 2/L bipolar transistors

Charge-collection measurements were carried out on HI/sup 2/L transistors in GaAs in order to determine the thickness of the equivalent sensitive volume to be used in calculating single-event-upset (SEU) rates for this technology and to set a lower limit to the critical charge. The measurements were in the form of pulse-height spectra measured between the base-emitter and collector-emitter contacts upon exposure to energetic protons, alpha particles, and sulfur ions. The sulfur data are consistent with the SEU-sensitive junction being the base-emitter junction with an equivalent sensitive volume of thickness 0.1 mu m for high-linear-energy-transfer (LET) particles. This value is a factor of two less than the thickness value previously used to estimate error rates in space and is a factor of three less than estimates based on alpha particles, which have lower LET. Comparison of the proton charge-collection data with earlier SEU measurements results in a revision of the estimate of the lower limit to the critical charge for HI/sup 2/L gate arrays to a value that is higher than previous estimates by more than a factor of two. The combination of reduced charge collection and higher critical charge implies that this technology will be considerably harder to SEUs than previously believed. >

Single-Event Upset (SEU) in a Dram with On-Chip Error Correction

The results are given of the first SEU measurements ever reported on IC devices with on-chip error correction. This method of SEU abatement could revolutionize the design of SEU-immune electronic systems.

Single-Event, Enhanced Single-Event and Dose-Rate Effects with Pulsed Proton Beams

Pulsed proton beams can create various upset effects in memory circuits. The response of the IDT 6116RH static RAM to these effects has been investigated over a range of flux extending from a single-event dominated region to a dose-rate dominated region. A surprisingly large intermediate region has been observed for the first time in which nuclear reactions add to background ionization to produce synergistic upset effects. From the viewpoint of memory reliability, the threshold of this synergistic region appears to be more important than the dose-rate upset threshold. Comparisons to gamma/electron dose-rate and single-event upset measurements are presented, as well as analysis and modelling of the results.

Single Event Upset Measurements of Gaas E-JFET RAMS

This paper reports the first single event upset measurements on a GaAs RAM. These measurements on fully operational 256-bit GaAs static RAMs were performed with 40-MeV protons at the NRL Cyclotron. The average upset cross section was 8 × 10-12 cm2/proton-bit. The single event upset cross section for these GaAs memories is comparable to the single event upset cross section measured in 40-MeV proton beams for representative Si memories. An estimate of the expected single event upset rate due to protons in 600 orbits for these GaAs memories is compared to representative Si memories.