Showing papers in "IEEE Transactions on Nuclear Science in 1996"
TL;DR: In this article, a design technique for storage elements which are insensitive to radiation-induced single-event upsets is proposed for implementation in high density ASICs and static RAMs using submicron CMOS technology.
Abstract: A novel design technique is proposed for storage elements which are insensitive to radiation-induced single-event upsets. This technique is suitable for implementation in high density ASICs and static RAMs using submicron CMOS technology.
1,096 citations
TL;DR: In this paper, ground level upsets have been observed in computer systems containing large amounts of random access memory (RAM). Atmospheric neutrons are most likely the major cause of the upsets based on measured data using the Weapons Neutron Research (WNR) neutron beam.
Abstract: Ground level upsets have been observed in computer systems containing large amounts of random access memory (RAM). Atmospheric neutrons are most likely the major cause of the upsets based on measured data using the Weapons Neutron Research (WNR) neutron beam.
614 citations
TL;DR: The occurrence of single-event upset (SEU) in aircraft electronics has evolved from a series of interesting anecdotal incidents to accepted fact as discussed by the authors, and the measured in-flight rates correlate with the atmospheric neutron flux, and that the rates can be calculated using laboratory SEU data.
Abstract: The occurrence of single-event upset (SEU) in aircraft electronics has evolved from a series of interesting anecdotal incidents to accepted fact. A study completed in 1992 demonstrated that SEUs are real, that the measured in-flight rates correlate with the atmospheric neutron flux, and that the rates can be calculated using laboratory SEU data. Once avionics SEU was shown to be an actual effect, it had to be dealt with in avionics designs. The major concern is in random access memories (RAMs), both static (SRAMs) and dynamic (DRAMs), because these microelectronic devices contain the largest number of bits, but other parts, such as microprocessors, are also potentially susceptible to upset. In addition, other single-event effects (SEEs), specifically latch-up and burnout, can also be induced by atmospheric neutrons.
380 citations
TL;DR: In this paper, the Sherbrooke APD-PET scanner has been evaluated in terms of resolution, sensitivity, count rate, random and scatter fractions, contrast and relative activity recovery as a function of object size.
Abstract: The design features and engineering constraints of a PET system based on avalanche photodiode (APD) detectors have been described in a previous report. Here, the authors present the initial results obtained with the Sherbrooke APD-PET scanner, a very high spatial resolution device designed for dynamic imaging of small and medium-sized laboratory animals such as rats, cats, rabbits and small monkeys. Its physical performance has been evaluated in terms of resolution, sensitivity, count rate, random and scatter fractions, contrast and relative activity recovery as a function of object size. The capabilities of the scanner for biomedical research applications have been demonstrated using phantom and animal studies.
251 citations
TL;DR: In this paper, basic mechanisms and ground-test data for radiation effects in solid-state imagers are reviewed, with a special emphasis on proton-induced effects on silicon charge-coupled devices (CCDs).
Abstract: Basic mechanisms and ground-test data for radiation effects in solid-state imagers are reviewed, with a special emphasis on proton-induced effects on silicon charge-coupled devices (CCDs). For the proton fluxes encountered in the space environment, both transient ionization and displacement damage effects arise from single-particle interactions. In the former case, individual proton tracks will be seen; in the latter, dark-current spikes (or hot pixels) and trapping states that cause degradation in charge-transfer efficiency will be observed. Proton-induced displacement damage effects on dark current and charge transfer are considered in detail, and the practical implications for shielding, device hardening, and ground testing are discussed.
189 citations
TL;DR: In this paper, the current status of device simulation of ionizing-radiation-induced charge collection and single-event upset (SEU), with an emphasis on significant results of recent years, is reviewed.
Abstract: In this paper we review the current status of device simulation of ionizing-radiation-induced charge collection and single-event upset (SEU), with an emphasis on significant results of recent years. We present an overview of device-modeling techniques applicable to the SEU problem and the unique challenges this task presents to the device modeler. We examine unloaded simulations of radiation-induced charge collection in simple p/n diodes, SEU in dynamic random access memories (DRAM's), and SEU in static random access memories (SRAM's). We conclude with a few thoughts on future issues likely to confront the SEU device modeler.
168 citations
TL;DR: In this paper, thermally-stimulated-current (TSC) and capacitance-voltage measurements on 370-1080 nm thermal, SIMOX, and bipolar-base oxides as functions of bias, dose rate, and temperature during irradiation were performed.
Abstract: We have performed thermally-stimulated-current (TSC) and capacitance-voltage measurements on 370-1080 nm thermal, SIMOX, and bipolar-base oxides as functions of bias, dose rate, and temperature during irradiation. Base oxides built in a development version of Analog Devices' RF25 process show much more interface-trap buildup than XFCB oxides. Both net-oxide-trap and interface-trap charge densities for RF25 capacitors are enhanced significantly during low-dose-rate or high-temperature irradiation at 0 V over high-rate, 25/spl deg/C exposures. TSC measurements show the increase in net-oxide-trap charge density is due to a decrease in trapped electron density with decreasing dose rate or increasing irradiation temperature (at least to 125/spl deg/C), and not by increased trapped hole density. Similar enhancement of net-oxide-trap and interface-trap charge density with decreasing dose rate is found for soft thermal oxides irradiated at 0 V, but not 5 V. These results strongly suggest that space charge effects associated with holes metastably trapped in the bulk of the oxide can cause the enhanced bipolar gain degradation seen at low dose rates and/or high temperatures in many technologies. No enhanced radiation-induced charge trapping is observed for low-dose-rate or high-temperature, 0 V irradiation of SIMOX capacitors. Implications for hardness assurance tests are discussed.
165 citations
TL;DR: In this article, the authors compared latchup from heavy particles in space with electrically induced latchup, and discussed the effects of technology changes and device scaling on latchup susceptibility.
Abstract: Changes in technology and device scaling have generally increased the sensitivity of VLSI devices to latchup from single interactions of heavy particles in space. This paper discusses latchup mechanisms, comparing latchup from heavy particles in space with electrically induced latchup, which has been more widely studied. The effects of technology changes and device scaling on latchup susceptibility are discussed as well. Test methods and the interpretation of latchup results are also included, along with predictions of the effects of device evolution and scaling on latchup susceptibility in space.
143 citations
TL;DR: In this article, the authors summarized many of those experimental studies and examined the problems, test methodologies, and experimental results of single event gate rupture (SEGR) and single event burnout (SEB) in a cosmic-ray environment.
Abstract: Numerous studies have revealed that vertical power MOSFETs are susceptible to single-event burnout (SEB) and single-event gate rupture (SEGR), resulting in degraded performance or even catastrophic failure when operated in a cosmic-ray environment like space. This paper summarizes many of those experimental studies and examines the problems, test methodologies, and experimental results. Previously unavailable information on SEGR is also provided.
137 citations
TL;DR: The impact of technology trends on the SEU hardness of epitaxial CMOSSRAMs is investigated using three-dimensional simulation and an application of SEU simulation, to the development of a 0.5-/spl mu/m radiation-hardened CMOS SRAM is presented.
Abstract: The impact of technology trends on the SEU hardness of epitaxial CMOS SRAMs is investigated using three-dimensional simulation. We study trends in SEU susceptibility with parameter variations across and within technology generations. Upset mechanisms for various strike locations and their dependence on gate-length scaling are explored. Such studies are useful for technology development and providing input for process and design decisions. An application of SEU simulation, to the development of a 0.5-/spl mu/m radiation-hardened CMOS SRAM is presented.
128 citations
TL;DR: In this article, the authors present an up-to-date overview of the single-event latchup (SEL) hard failure mode encountered in electronic device applications involving heavy ion environment.
Abstract: This paper presents an up-to-date overview of the single-event latchup (SEL) hard failure mode encountered in electronic device applications involving heavy ion environment. This phenomenon is specific to CMOS technology. Single-event latchup is discussed after a short description of the effects induced by the interaction of a heavy ion with silicon. Understanding these effects is necessary to understand the different failures. This paper includes a description of the latchup phenomenon and the different triggering modes, reviews of models and hardening solutions, and finally presents new developments in simulation approaches.
TL;DR: A review of analytical, semianalytical, and simulation models developed to help explain single-event effects of power MOSFETs is presented and their merits and limitations are explained.
Abstract: Heavy ions can trigger catastrophic failure modes in power metal-oxide-semiconductor field-effect transistors (MOSFETs). Single-event effects (SEE), namely, single-event burnout (SEB), and single-event gate rupture (SEGR), of power MOSFETs are catastrophic failure mechanisms that are initiated by the passage of a heavy ion through the device structure. Various analytical, semianalytical, and simulation models have been developed to help explain these phenomena. This paper presents a review of these models and explains their merits and limitations. New results are included to illustrate the approaches.
TL;DR: In this article, the authors proposed different models to analyze the sensitivity of CMOS SRAM cells and the available data of SEU characterizations are finally compiled, based on the analysis of the various structures of SOI transistors, charge collection mechanisms are presented.
Abstract: Due to their limited sensitive volumes for charge collection, silicon on insulator (SOI) technologies are good candidates for any microelectronic device operating in a space environment. While being insensitive to latchup phenomena, SOI devices may experience single-event effects (SEE's). Based on the analysis of the various structures of SOI transistors, charge collection mechanisms are presented. The different models proposed to analyze the sensitivity of CMOS SRAM cells are then discussed. The available data of SEU characterizations are finally compiled.
TL;DR: In this article, a qualitative model is presented which identifies the physical mechanism responsible for excess base current in lateral PNP bipolar junction transistors, which is due to an increase in base current as a result of recombination at the surface of the device.
Abstract: Ionizing-radiation-induced gain degradation in lateral PNP bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A qualitative model is presented which identifies the physical mechanism responsible for excess base current. The increase in surface recombination velocity due to interface traps results in an increase in excess base current and the positive oxide charge moderates the increase in excess base current and changes the slope of the current-voltage characteristics. Analytical and empirical models have been developed to quantitatively describe the excess base current response to ionizing radiation. It is shown that the surface recombination velocity dominates the excess base current response to total dose.
TL;DR: In this paper, an empirical model for proton induced single event upset (SEU) is presented based on heavy ion data, and will improve the previous 'two parameters' Bendel model.
Abstract: This paper presents an empirical model for proton induced Single Event Upset (SEU). This model is based on heavy ion data, and will improve the previous 'two parameters' Bendel model. Application to various parts is presented.
TL;DR: The 20-year history of ground studies and spacecraft studies of spontaneous pulsed discharges is reviewed in this paper, where the authors show that the data from space are not sufficient to unambiguously point to a few specific solutions.
Abstract: The charging of spacecraft components by high energy radiation can result in spontaneous pulsed discharges. The pulses can interrupt normal operations of spacecraft electronics. The 20-year history of ground studies and spacecraft studies of this phenomenon are reviewed. The data from space are not sufficient to unambiguously point to a few specific solutions. The ground based data continue to find more problem areas the longer one looks. As spacecraft become more complex and carry less radiation shielding, the charging and discharging of insulators is becoming a more critical problem area. Ground experiments indicate that solutions for spacecraft are multiple and diverse, and many technical details are reviewed or introduced here.
TL;DR: In this article, the authors used a strong static homogeneous magnetic field to increase PET resolution by reducing the effects of positron range and photon non-collinearity, which is the fundamental limiting factor of large PET scanner resolution.
Abstract: Positron emission tomography (PET) relies upon the detection of photons resulting from the annihilation of positrons emitted by a radiopharmaceutical. The combination of images obtained with PET and magnetic resonance imaging (MRI) have begun to greatly enhance the study of many physiological processes. A combined MRI-PET scanner could alleviate much of the spatial and temporal coregistration difficulties currently encountered in utilizing images from these complementary imaging modalities. In addition, the resolution of the PET scanner could be improved by the effects of the magnetic field. In this computer study, the utilization of a strong static homogeneous magnetic field to increase PET resolution by reducing the effects of positron range and photon noncollinearity was investigated, The results reveal that significant enhancement of resolution can be attained, For example, an approximately 27% increase in resolution is predicted for a PET scanner incorporating a 10-Tesla magnetic field. Most of this gain in resolution is due to magnetic confinement of the emitted positrons. Although the magnetic field does mix some positronium states resulting in slightly less photon noncollinearity, this reduction does not significantly affect resolution. Photon noncollinearity remains as the fundamental limiting factor of large PET scanner resolution.
TL;DR: In this paper, the authors used energy particle data gathered on the CRRES spacecraft to produce new and more accurate models of high-energy electron and proton fluxes as well as total dose models out to geosynchronous altitude.
Abstract: Energetic particle data gathered on the CRRES spacecraft have been used to produce new and more accurate models of high-energy electron and proton fluxes as well as total dose models out to geosynchronous altitude. In addition to providing the information necessary to improve designs and operations of near-Earth space systems, the models also give insight into the dynamic behavior of the radiation belts not considered in previous models. Sample orbit runs are compared to the earlier NASA models to elucidate their weaknesses. Areas of improved understanding in the radiation environment, gained from CRRES, and how they impact systems are summarized.
TL;DR: The current standard models of the radiation belt environment have many shortcomings, not the least of which is their extreme age as discussed by the authors, and most of the data used for them were acquired in the 1960's and early 1970's.
Abstract: The current standard models of the radiation-belt environment have many shortcomings, not the least of which is their extreme age. Most of the data used for them were acquired in the 1960's and early 1970's. Problems with the present models, and the ways in which data from more recent missions are being or can be used to create new models with improved functionality, are described. The phenomenology of the radiation belts, the effects on space systems, and geomagnetic coordinates and modeling are discussed. Errors found in present models, their functional limitations, and problems with their implementation and use are detailed. New modeling must address problems at low altitudes with the south Atlantic anomaly, east-west asymmetries and solar cycle variations, and at high altitudes with the highly dynamic electron environment. The important issues in space environment modeling from the point of view of usability and relationship with effects evaluation are presented. New sources of data are discussed. Future requirements in the data, models, and analysis tools areas are presented.
TL;DR: In this paper, the authors reviewed common practices for predicting rates of single-event effects in microelectronics in space environments and compared them with alternative approaches with discussion of dominant modeling parameters, assumptions, and limitations and the impact on prediction results.
Abstract: Common practices for predicting rates of single-event effects (SEE) in microelectronics in space environments are reviewed. Established rate-prediction models are discussed, and comparison is drawn between alternative approaches with discussion of dominant modeling parameters, assumptions, and limitations and the impact on prediction results. Areas of current uncertainty are identified. Approaches for obtaining model parameters from test data are reviewed. The methods are illustrated by example calculations that explore the sensitivity of results on model parameter choices.
TL;DR: In this article, single event burnout was seen in power MOSFETs exposed to high energy neutrons and high energy protons with a rated voltage /spl ges/400 volts.
Abstract: Single event burnout was seen in power MOSFETs exposed to high energy neutrons. Devices with rated voltage /spl ges/400 volts exhibited burnout at substantially less than the rated voltage. Tests with high energy protons gave similar results. Burnout was also seen in limited tests with lower energy protons and neutrons. Correlations with heavy-ion data are discussed. Accelerator proton data gave favorable comparisons with burnout rates measured on the APEX spacecraft. Implications for burnout at lower altitudes are also discussed.
TL;DR: Two laboratory techniques for measuring SEE, one involving a pulsed laser and the other /sup 252/Cf, are described in detail in this paper, which establishes the limits of each technique.
Abstract: Integrated circuits are currently tested at accelerators for their susceptibility to single-event effects (SEE's). However, because of the cost and limited accessibility associated with accelerator testing, there is considerable interest in developing alternate testing methods. Two laboratory techniques for measuring SEE, one involving a pulsed laser and the other /sup 252/Cf, are described in detail in this paper. The pulsed laser provides information on the spatial and temporal dependence of SEE, information that has proven invaluable in understanding and mitigating SEE in spite of the differences in the physical mechanisms responsible for SEE induced by light and by ions. Considerable effort has been expended on developing /sup 252/Cf as a laboratory test for SEE, but the technique has not found wide use because it is severely limited by the low energy and short range of the emitted ions that are unable to reach junctions either covered with dielectric layers or deep below the surface. In fact, there are documented cases where single-event latchup (SEL) testing with /sup 252/Cf gave significantly different results from accelerator testing. A detailed comparison of laboratory and accelerator SEE data is presented in this review in order to establish the limits of each technique.
TL;DR: A review of the literature on single-event radiation effects on MOS integrated-circuit dynamic random access memories (DRAMs) is presented in this paper, where the sources of single event (SE) radiation particles, causes of circuit information loss, experimental observations of SE information upset, technological developments for error mitigation, and relationships of developmental trends to SE vulnerability are discussed.
Abstract: A review of the literature on single-event radiation effects (SEE) on MOS integrated-circuit dynamic random access memories (DRAMs) is presented. The sources of single-event (SE) radiation particles, causes of circuit information loss, experimental observations of SE information upset, technological developments for error mitigation, and relationships of developmental trends to SE vulnerability are discussed.
TL;DR: In this article, the authors used deep level transient spectroscopy to investigate defects in high resistivity silicon diodes after neutron irradiation and found that the leakage current in the dioded is a factor of 50 to 600 greater than expected from standard Shockley-Read-Hall (SRH) theory for the observed defect concentration.
Abstract: Deep level transient spectroscopy has been used to investigate defects in high resistivity silicon diodes after neutron irradiation. Three defects have been correlated with the leakage current. The leakage current in the diodes is found to be a factor of 50 to 600 greater than expected from standard Shockley-Read-Hall (SRH) theory for the observed defect-concentrations. The results can be explained by an enhancement factor due to intercentre transfer of charge between defects in close proximity to each other. It is proposed that a possible mechanism for this process is rapid, direct transfer between a deep donor state and a deep acceptor state. An unidentified defect is observed at E/sub C/-0.45/spl plusmn/0.02 eV which anneals at /spl sim/700/spl deg/C. This defect is correlated to excess leakage current in both diodes and charge coupled devices.
TL;DR: For particular bias conditions, it is shown that a device can fail due to either single event gate rupture (SEGR) or to single event burnout (SEB) as mentioned in this paper.
Abstract: For particular bias conditions, it is shown that a device can fail due to either single-event gate rupture (SEGR) or to single-event burnout (SEB). The likelihood of triggering SEGR is shown to be dependent on the ion impact position. Hardening techniques are suggested.
TL;DR: In this article, a new and complete analysis of GOES proton data and high-energy heavy-ion fluences from the University of Chicago Cosmic Ray Telescope on IMP-8 is presented.
Abstract: We calculate single event upset (SEU) rates due to protons, alphas, and heavier ions in two satellite systems for the major solar particle events of 1989-92, using a new and complete analysis of GOES proton data and high-energy heavy-ion fluences from the University of Chicago Cosmic Ray Telescope on IMP-8. These measurements cover the entire range of energies relevant to SEU studies and therefore overcome shortcomings of previous studies, which relied upon theoretical or semi-empirical estimates of high-energy heavy-ion spectra. We compare our results to the observed SEU rates in these events. The SEU rates in one device (AMD 93L422s on LEASATs) were overwhelmingly dominated by protons. However, even after taking into account uncertainties in the ground-test cross-section data, we find that at least /spl sim/45% of the SEUs in the other device (Fairchild 93L422s on TDRS-1) must have been caused by heavy ions. Our results demonstrate that both protons and heavy ions must be considered in order to make a reliable assessment of SEU vulnerabilities. Furthermore, the GOES/Chicago database of solar particle events provides a basis for making accurate solar particle SEU calculations and credible worst-case estimates. In particular, measurements of the historic solar particle events of October 1989 are used in "worst week" and "worst day" environment models in CREME96, a revision of NRL's Cosmic Ray Effects on MicroElectronics code.
TL;DR: In this paper, the effect of very low dose rate irradiation on linear bipolar devices with super/spl beta/input transistors was investigated and the results were shown to be at 0.001 and 0.002 rad(Si)/s.
Abstract: The effect of very low dose rate irradiation is investigated for several linear bipolar devices that are sensitive to enhanced low dose-rate damage, including one device with super-/spl beta/ input transistors. New results are included at 0.001 and 0.002 rad(Si)/s. Irradiations at elevated temperature at high dose rate are compared with room temperature irradiation at very low dose rate. Possible mechanisms for enhanced damage are discussed.
TL;DR: Analog and mixed-signal integrated circuits are also susceptible to single-event effects, but they have rarely been tested as discussed by the authors, thus, they require modified test techniques and data analysis.
Abstract: Analog and mixed-signal integrated circuits are also susceptible to single-event effects, but they have rarely been tested. Analog circuit single-particle transients require modified test techniques and data analysis. Existing work is reviewed and future concerns are outlined.
TL;DR: In this paper, the trapped charge density in the LOCOS bird's beak resulting from irradiating a conventional NMOSFET has been analyzed using a 2D finite element simulation.
Abstract: The trapped charge density in the LOCOS bird's beak resulting from irradiating a conventional NMOSFET has been analysed using a 2D finite element simulation. This paper shows a maximum of trapped charge density in the bird's beak region. The resulting voltage shift of the lateral parasitic transistor in the bird's beak region induces a high leakage current, and prevents any normal circuit operation. The silicon doping level, the supply voltage and the bird's beak shape are key parameters for device hardening of rad-tolerant technologies.
TL;DR: In this paper, two types of optocouplers with different physical configurations were investigated for radiation damage from gamma rays and protons, and it was shown that far more damage occurs from protons because of displacement damage, which reduces the photoresponse of the phototransistor and causes severe degradation in LED light output.
Abstract: Radiation damage from gamma rays and protons is investigated for two types of optocouplers with different physical configurations. Far more damage occurs from protons because of displacement damage, which reduces the photoresponse of the phototransistor and causes severe degradation in LED light output for one of the two device types. The other device type was far more resistant to radiation, primarily because it used a shorter wavelength LED that was relatively unaffected by protons.