Neutron-induced Single Event Effects 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.

Neutron Irradiation Testing and Monte Carlo Simulation of a Xilinx Zynq-7000 System on Chip

The reliability of nanoscale electronic systems is important in various applications. However, they are becoming increasingly vulnerable to atmospheric neutrons. This research conducted spallation neutron irradiations on a Xilinx Zynq-7000 system on a chip using the China Spallation Neutron Source. The results were analyzed in combination with a Monte Carlo simulation to explore the impact of atmospheric neutrons on the single event effects of the target system on chip. Meanwhile, the contribution of thermal neutrons to the chip’s single event effect susceptibility was also assessed. It was found that absorbing thermal neutrons with a 2 mm Cd sheet can protect against the single event effect on the system on the chip by about 44.4%. The effects of B and Hf elements, inside the device, on a single event effect of the Xilinx Zynq-7000 system on chip were evaluated too. Additionally, it was discovered that 10B interacting with thermal neutrons was the primary cause of the thermal neutron-induced single event effect in the system on chip. Although Hf has a high neutron capture cross section, its presence does not significantly affect the sensitivity to single event effects. However, during atmospheric neutron irradiation, the presence of Hf increases the possibility of depositing the total dose in the tested chip.

Mechanism and Equivalence of Single Event Effects Induced by 14 MeV Neutrons in High-Speed QDR SRAM

Single-bit upset (SBU) and multiple-cell upset (MCU) features of high-speed QDR-SRAM are revealed under the 14 MeV neutron irradiation. By comparing with the high-altitude real atmosphere test results directly, the equivalence of 14 MeV neutrons for atmospheric neutron-induced single event effect (SEE) evaluation is investigated. It is found that, compared with the 65 nm planar device, the SBU cross-section of 14 nm FinFET SRAM decreases to 1/58 and the proportion of MCU shows little difference, which results from the narrow channel between fin and substrate caused by shallow channel isolation in 14 nm FinFET process, and the charge sharing effect between fins is weakened. The SBU and MCU cross-sections under the 14 MeV neutron irradiation are underestimated by 22.8% and 85.7%, respectively. Besides, the probability and maximum size of MCU are both smaller than those in the real atmosphere. The MCU shape tends to be vertical, resulting from the smaller vertical spacing of sensitive volumes (about 100 nm). Further Monte-Carlo simulation shows that the total yield of secondary ions produced by atmospheric neutrons is higher than that produced by 14 MeV neutrons. Major Components of the “useful” products are p, Si, α, etc., which are the main cause of SBU events. Besides, compared with 14 MeV neutrons, atmospheric neutrons generate more kinds of secondary ions in the SV within the scope from p to W, and the diverse high-Z elements, such as W, Ta, Hf, etc., are the main cause of MCU events. Moreover, the maximum LET of secondary ions can reach 31.5 MeV·cm2/mg. The equivalence of using 14 MeV neutrons for atmospheric neutron-induced SEE evaluation is closely related to the critical charge of the device under test.

Neutron-induced single event effect in Xilinx 16nm MPSoC configuration RAM (CRAM) using white neutron and 2.72~81.8meV neutron in CSNS-BL20

ABSTRACT Multi-Processor System on Chip is widely used in 5G wireless, advanced driver assistance system, industrial internet of things and other fields, it suffers the risk from neutron-induced single event effects. In the China Spallation Neutron Source BL20 neutron performance measurement room, the white and 2.72~81.8meV neutrons are obtained by adjusting the phase of the choppers, and the neutron-induced single event effect experiments on configuration memory of the Xilinx 16nm MPSoC were carried out. Single bit upset and single event functional interruption events were detected in various irradiation modes. The results show that 16nm MPSoC is sensitive to low energy neutrons because of 10B. Analysis shows that 2.72~81.8meV neutrons take up about 7.1% of the white neutron, but the contribution to the entire white neutron inducing single event upsets reaches 63%. Further analysis manifests that neutrons in the thermal energy region account for about 9.6% in white neutron irradiation mode, but their contribution to single event upset is about 44%. And for 2.72~81.8meV neutron irradiation mode, neutrons from 2.72 to 10meV and 10 to 81.8meV contributed 46% and 54% of soft errors, respectively. Therefore, for certain radiation fields, it is recommended to focus on the impact of low energy neutrons.

Neutron-Induced Radiation Effects in UMOS Transistor

Ground level electronics and avionics systems may suffer from radiation effects induced by neutrons. Neutrons can induce radiation effects in electronic devices via fusion-evaporation nuclear reactions, but few studies have been reported for technologies such as UMOSFET. In this work, estimates and experimental studies on neutron-induced radiation effects via nuclear reactions in a Si-based UMOSFET are presented. Methods for probability estimates of neutron-induced Single-Event Effects (SEEs) in Si-based power transistors and neutron beam energy measurement is presented. The energy spectrum of a UMOSFET subject to fast neutron irradiation was then compared to that of a high charge collection efficiency silicon particle detector.

Failure Analysis of Atmospheric Neutron-Induced Single Event Burnout of a Commercial SiC MOSFET

Dealing with electronic devices for high reliability applications in terrestrial environments, neutron-induced Single Event Effects must be investigated. In this paper, the experimental observation of an atmospheric-like neutron-induced Single Event Burnout (SEB) on a packaged commercial SiC power MOSFET is presented after irradiation at ISIS-ChipIr. The effects of the SEB in the electrical properties of the MOSFET are established, and the SiC damaged zone is observed by scanning electron microscopy. Based on this failure analysis at the die level, the distinct stages during the SEB mechanism can be defined. The sensitive volume where the secondary particle deposited enough energy to trigger the SEB mechanism is identified and located inside the SiC n-drift epitaxial layer near the epitaxial layer/substrate junction.

Fast neutrons at LNL Legnaro

In this contribution we describe NEPIR, the fast-neutron irradiation facility under construction at the 70 MeV cyclotron SPES facility of the INFN laboratory of Legnaro (LNL). NEPIR will be constructed in stages, according to the available funds. The initial configuration, based on a thick Be neutron production target, will be operational in 2022; it will be used for shielding studies against fast neutrons for space applications and to investigate neutron-induced Single Event Effects (SEE) in microelectronic devices and systems. In its final configuration NEPIR will have two target systems: one will deliver a Quasi Mono-energetic Neutron (QMN) beam, of general interest, with an adjustable energy peak in the 20–70 MeV range; the second target will deliver a specialized continuous energy neutron beam for studying the effects of fast neutrons produced in cosmic ray air-showers in electronic devices and systems. We review the use of NEPIR to characterize the sensitivity of electronics, describe the neutron production targets and the facility layout. In closing we describe ways, presently under investigation, to use the 15 MV XTU Tandem of LNL to produce nearly monochromatic fast neutrons that would complement the QMN system by allowing one to probe for SEE below 20 MeV.

CoolGAL: a Galinstan bathed Be fast neutron production target at the NEPIR facility

In this contribution, we present the CoolGAL fast neutron production target system, to be used in the initial phase of the NEPIR irradiation beamline at the SPES facility, that will be operational in 2022. Initially, NEPIR will be used for shielding studies against fast neutrons for space applications and to investigate neutron-induced single event effects in microelectronic devices and systems. In CoolGAL, the neutron production component, a thick Be cylinder, is immersed in a static bath of Galinstan, a liquid alloy of Ga, In and Sn, contained by an outer water cooled copper cladding. MCNPX calculations indicate that, by using a 1 μA current of 70 MeV protons, it can produce a fast neutron energy spectrum that is somewhat flat the 30-65 MeV energy range and with a sharp cut-off at the beam energy. At the standard test point, located 2.6 m downstream from the source, the beam spot diameter, defined by the peculiar collimation scheme of the initial phase of NEPIR, is 10 cm and the integral fast neutron flux is Φn(1< En<65 MeV) ~ 3×106 n cm-2s-1. Using proton beams with two different energies, one can calculate, by subtraction, the effects due to the neutrons in the energy interval defined by the two cut-off values. Preliminary results of ANSYS calculations, for a 1 μA proton current of 70 MeV protons (70 W), show a limited regime temperature (28 °C) of the Be component, capable of ensuring the exceptional safety level required for the operation at SPES. The thermal reliability of CoolGAL is very promising for future developments that require higher proton currents.

Impact of Device Structure on Neutron-Induced Single-Event Effect in SiC MOSFETs

Neutron single event effect (SEE) tolerance of SiC power MOSFETs with different drift region design were evaluated. The SEE is detected over the SEE threshold voltage (VSEE). The failure rate increases exponentially as the drain voltage increases above VSEE. The device with higher avalanche breakdown voltage has higher SEE threshold voltage. The neutron SEE tolerance of MOSFETs and PiN diodes of the same epitaxial structure were also evaluated. There was no significant difference in the neutron SEE tolerance of these devices.

Impact of Nuclear Data Uncertainty in the Modeling of Neutron-Induced Recoil Atom Energy Distributions in Silicon

Recoil ion distributions in silicon and the resulting distribution of the linear energy transfer (LET) are important metrics in microdosimetric studies and in the investigation of neutron-induced single-event effects. A rigorous methodology is presented for quantifying the uncertainty in these metrics due to the underlying uncertainty contributors, including that due to the nuclear data, recoil ion electronic stopping power, and incident neutron spectrum. The methodology uses a Monte Carlo-based approach so that the nonlinear uncertainty propagation is rigorously treated as the response function folded with the full incident neutron spectrum. The uncertainty is captured in the form of both recoil energy and LET-dependent covariance matrices. The uncertainty contributions from the nuclear data are shown to have strong energy-dependent correlations which are comparable in magnitude to that from the uncertainty found in the spectrum characterization for high fidelity reference neutron fields. The uncertainty from the stopping power has the largest magnitude of the largest contributors, but it shows a very strong energy-dependent correlation that translates into a systematic uncertainty that may cancel out in many applications.

The Effect of 1–10-MeV Neutrons on the JESD89 Test Standard

The JESD89 test standard defines how terrestrial neutron testing is conducted [1]. The test standard covers a number of different types of radiation used for testing, including protons, neutrons, and alphas, and different types of testing, including life testing and accelerated testing. Broad-spectrum neutron testing is the most common type of accelerated radiation testing for the terrestrial radiation environment. Unlike most test standards, the JESD89 defines the minimum energy for determining the cumulative fluence for the deployed and test environment. Currently, the minimum energy is set at 10 MeV. As the test standard is currently being rewritten, changing the minimum energy to 1 MeV is being explored, because it is believed that the onset to neutron-induced single-event effects (SEEs) is less than 10 MeV. There are three separate problems with lowering the minimum energy: determining whether electronics have a sensitivity to neutron-induced SEEs below 10 MeV, determining whether the test spectra match the terrestrial environment in the 1-10-MeV range, and the measurement error caused by not including the fluence from 1 to 10 MeV. In this paper, we present information on these factors and whether the minimum energy should be lowered to 1 MeV.

Possible atmospheric-like neutron beams at CSNS

The China Spallation Neutron Source (CSNS) has started commissioning in early 2018. The neutron spectrum from the tungsten target bombarded by a 1.6 GeV proton beam is very wide, namely with characteristics of a white neutron spectrum. In this paper two white neutron beams schemed at CSNS are simulated by using the FLUKA code. And the beam spectrum and intensity are compared with that from other neutron sources in the world. The fidelity for the chip irradiation experiments by using the neutron spectra of these two white-neutron beam lines is estimated. These atmospheric-like neutron beams will be the first white neutron beam lines at CSNS and more intensive ones for carrying out an accelerated test of the neutron-induced single event effect (SEE) will be available in a few years.

Mechanisms of atmospheric neutron-induced single event upsets in nanometric SOI and bulk SRAM devices based on experiment-verified simulation tool**Project supported by the National Natural Science Foundation of China (Grant No. 11505033), the Science and Technology Research Project of Guangdong Province, China (Grant Nos. 2015B090901048 and 2017B090901068), and the Science and Technology Plan Project of Guangzhou, China (Grant No. 201707010186).

In this paper, a simulation tool named the neutron-induced single event effect predictive platform (NSEEP2) is proposed to reveal the mechanism of atmospheric neutron-induced single event effect (SEE) in an electronic device, based on heavy-ion data and Monte-Carlo neutron transport simulation. The detailed metallization architecture and sensitive volume topology of a nanometric static random access memory (SRAM) device can be considered to calculate the real-time soft error rate (RTSER) in the applied environment accurately. The validity of this tool is verified by real-time experimental results. In addition, based on the NSEEP2, RTSERs of 90 nm–32 nm silicon on insulator (SOI) and bulk SRAM device under various ambient conditions are predicted and analyzed to evaluate the neutron SEE sensitivity and reveal the underlying mechanism. It is found that as the feature size shrinks, the change trends of neutron SEE sensitivity of bulk and SOI technologies are opposite, which can be attributed to the different MBU performances. The RTSER of bulk technology is always 2.8–64 times higher than that of SOI technology, depending on the technology node, solar activity, and flight height.

ANEM: A rotating composite target to produce an atmospheric-like neutron beam at the LNL SPES facility

A fast neutron (E> MeV) irradiation facility is under development at the 70 MeV SPES proton cyclotron at LNL (Legnaro, Italy) to investigate neutron-induced Single Event Effects (SEE) in microelectronic devices and systems. After an overview on neutron-induced SEE in electronics, we report on the progress in the design of ANEM (Atmospheric Neutron EMulator), a water-cooled rotating target made of Be and W to produce neutrons with an energy spectrum similar to that of neutrons produced by cosmic rays at sea-level. In ANEM, the protons from the cyclotron alternatively impinge on two circular sectors of Be and W of different areas; the effective neutron spectrum is a weighted combination of the spectra from the two sectors. In this contribution, we present the results of thermal-mechanical Finite Element Analysis (ANSYS) calculations of the performance of the ANEM prototype. The calculations at this stage indicate that ANEM can deliver fast neutrons with an atmospheric-like energy spectrum and with an integral flux [Formula: see text](1-70 MeV) [Formula: see text]107 n cm[Formula: see text]s[Formula: see text] that is 3×109 more intense than the natural one at sea-level: a very competitive flux for SEE testing.

A Neutron-induced Single Event Effects Facility at the 70 MeV Cyclotron of LNL-INFN

We describe a proposed neutron irradiation facility for studyi ng neutron-i nduced Single Event Effects (SEE) in microelectronic components and systems at the new variable energy high current proton cyclotron (35-70 MeV; 750μA) soon to be operational at LNL. We descri be the progress in designing two neutron production targets to furnish continuous atmospheric-like neutron differential spectra: a W-based thick target (to stop 70 MeV protons), and an innovative composite target made of Beryllium and Tantal um or Lead. We also describe the layout of the facility that will also house quasi-monoenergetic neutron (QMN) and direct proton beam lines. The thick target beam line could be available as soon as the new cyclotron is commissioned. The composite target and QMN beam lines, to be designed in concert, would be completed soon after.

The QMN Beam Line of the Neutron-induced Single Event Effects Facility at the 70 MeV Cyclotron of LNL-INFN

The SPES project, based on a variable energy high current proton cyclotron (35-70 MeV; 750μA), soon to be operational at LNL, foresees a neutron irradiation facility for Single Event Effects (SEE) studies on microelectronic components and systems. The proposed facility will comprise both a beam line with continuous energy atmospheric-like neutron production targets, and a Quasi Mono-energetic Neutron (QMN) beam line. A direct proton beam line is also foreseen. Here we describe the general features of the proposed QMN beam line. The quasi mono-energetic neutrons will be produced in various thin Be and Li targets and the spent proton beam will be magnetically deflected towards a beam dump. The layout of the facility with a multi-angle collimator scheme for tail corrections is presented and the proton currents necessary to deliver high neutron fluxes using thin Be targets are estimated.

Transient device simulation of neutron-induced failure in IGBT: A first step for developing a compact predictive model

In atmospheric environment, neutron-induced single event effects are known to be a concern for electronic devices reliability. The effect of atmospheric radiation on integrated technologies (mainly single event upsets and latchup on CMOS) has been extensively investigated during the last 3 decades and testing standards have even been developed (e.g. JESD89a, IEC TS 62396). Moreover at present, a good knowledge of the physical mechanisms at stake allows to use efficient prediction tools which are now mature enough to be transferred to academic and industrial end-users [1,2]. Those tools are in particular useful to predict the expected failure rate of a given technology with very little technological knowledge.Atmospheric radiation-induced power devices failures are not treated as well. Even though numerous studies have been performed, no standard exist for testing devices in atmospheric environment. On the other hand, the complexity of the failure modes at play makes it very difficult to develop efficient prediction tools.In this paper, an analysis of the physical mechanisms at play is performed using 2D TCAD simulation tool. In particular, the sensitive region as well as the role of the temperature has been investigated. Moreover the simulated failure mode is compared to the phenomenological model described in the literature. The goal of this paper is to determine whether some simplifications in the triggering mode for a failure can be done in order to ease the development of analytical prediction tools.

Vulnerability of CMOS image sensors in megajoule class laser harsh environment

CMOS image sensors (CIS) are promising candidates as part of optical imagers for the plasma diagnostics devoted to the study of fusion by inertial confinement. However, the harsh radiative environment of Megajoule Class Lasers threatens the performances of these optical sensors. In this paper, the vulnerability of CIS to the transient and mixed pulsed radiation environment associated with such facilities is investigated during an experiment at the OMEGA facility at the Laboratory for Laser Energetics (LLE), Rochester, NY, USA. The transient and permanent effects of the 14 MeV neutron pulse on CIS are presented. The behavior of the tested CIS shows that active pixel sensors (APS) exhibit a better hardness to this harsh environment than a CCD. A first order extrapolation of the reported results to the higher level of radiation expected for Megajoule Class Laser facilities (Laser Megajoule in France or National Ignition Facility in the USA) shows that temporarily saturated pixels due to transient neutron-induced single event effects will be the major issue for the development of radiation-tolerant plasma diagnostic instruments whereas the permanent degradation of the CIS related to displacement damage or total ionizing dose effects could be reduced by applying well known mitigation techniques.

Application of thin-film breakdown counters for characterization of neutron field of the VESUVIO instrument at the ISIS spallation source

The high-energy neutron field of the VESUVIO instrument at the ISIS facility has been characterized using the technique of thin-film breakdown counters (TFBC). The technique utilizes neutron-induced fission reactions of natU and 209Bi with detection of fission fragments by TFBCs. Experimentally determined count rates of the fragments are ≈50% higher than those calculated using spectral neutron flux simulated with the MCNPX code. This work is a part of the project to develop ChipIr, a new dedicated facility for the accelerated testing of electronic components and systems for neutron-induced single event effects in the new Target Station 2 at ISIS. The TFBC technique has shown to be applicable for on-line monitoring of the neutron flux in the neutron energy range 1–800MeV at the position of the device under test (DUT).

Neutron production targets for a new Single Event Effects facility at the 70 MeV Cyclotron of LNL-INFN

A high-current (500 μA) variable energy (35-70 MeV) proton cyclotron is under construction at the INFN LNL for the SPES project and will be commissioned in 2014. This opens up the prospect of a high flux neutron irradiation facility in Italy that could perform various research activities, in particular studies of Single Event Effects (SEE) induced in microelectronic devices and systems by atmospheric neutrons at sea level. In this paper we first review neutron-induced SEE, describe neutron testing facilities and briefly illustrate the project at LNL. We then describe two types of high power production targets under design to produce neutrons with a continuous atmospheric-like differential energy spectra in the energy range accessible to the accelerator. One target is a high power W-based thick target that will completely stop the 70 MeV protons. Another target, under preliminary study, is based on a multi-material target made, in this case, of two different materials, light (Be) and a heavy material such as Ta or Pb.