Single Event Effects Research Articles

Evaluating the broad neutron spectrum of ANIS

The Atmospheric Neutron Irradiation Spectrometer (ANIS) is a new member of the worldwide neutron irradiation facilities. It was developed at the China Spallation Neutron Source (CSNS), producing the atmospheric-like neutrons from meV to GeV with high neutron flux simultaneously. Because of the differences between ANIS spectrum and the atmospheric neutron spectrum in the real environment, the neutron spectrum at ANIS should be evaluated to ensure the validity for the accelerated single event effects (SEEs) testing of electronics. In this study, the broad neutron spectrum at ANIS was obtained from the Monte Carlo simulation. An analytic expression of this neutron spectrum was provided. Calculations of the single error rate (SER) for the SRAM and DRAM devices with specific cross-section were also performed. By calculating the SER ratio compared with JESD89A and IEC TS 62396-1 standards, the deviation of the broad neutron spectrum at ANIS from that in the atmospheric neutron environment can be well predicted. This study evaluates the reliability of ANIS neutron spectrum for the first time.

Design optimization of a Dual-Interlocked-Cell in 65 nm CMOS tolerant to Single Event Upsets

Dual-Interlocked-Cell (DICE) latches are tolerant to Single Event Effects (SEE) by design owing to intrinsic redundancy. In nanometric technologies, as in the 65 nm scale, there are new SEE vulnerabilities associated with charge sharing between nodes. Herein we present a systematic analysis of the robustness against radiation using a simulation software tool for analog and mixed-signal circuits (AFTU) that emulates the possible effects generated by particle impacts. In this paper, we evaluate the influence of SEE on circuit performance using this tool as an RHbD assessment for designers. An exhaustive study of the possible vulnerabilities of the DICE architecture is performed, including an evaluation of the proximity between critical nodes at the layout level. As a result, we propose several modifications to the cell implementation to optimize its robustness against Single Event Upsets (SEU). An assortment of five designs with different variations of the original DICE scheme was sent for fabrication on a new chip and tested under ion beams, with promising results showing a clear improvement in the SEU sensitivity of the cell. The best results come from a redesign of the load circuitry to avoid a SET2SEU effect and full interleaved layout to avoid charge sharing effects after a single event.

Research on heavy ion irradiation effects on SOI SRAM

SRAM based on SOI devices has been widely used in aerospace storage devices due to its good electrical characteristics and radiation resistance. However, with the development of semiconductor technology, the feature size of devices continues to shrink, and the irradiation effects of high-energy ions have become increasingly serious. Single event effect has become the biggest threat to the failure of the spacecraft. A mixed-simulation method was used to research the heavy ion irradiation effects on SOI SRAM. SRAM consists of two coupled inverters. Firstly, the voltage changes of the inverter and SRAM output nodes under heavy ion irradiation were compared and analyzed, then the influence of the device itself and heavy ion parameters on the single particle flipping effect of the SRAM is investigated, and finally the necessary conditions for the flipping of the stored information in the SRAM are discussed and derived. The results show that heavy ion incidence does not permanently change the final state of the inverter; devices in the off state in the SRAM will undergo information flipping only when they are irradiated by heavy ions, and the threshold voltage of the N-type MOSFET is lower than that of the P-type MOSFET; an increase in the penetration depth will accelerate the flipping speed of the SRAM, but when the LET is high, the influence of the penetration depth on the flipping speed decreases; the change of the stored information in the SRAM is the result of the combined effect of pulse width and pulse height.

Effect of substrate thinning on heavy ion induced single event effect in silicon carbide power junction barrier Schottky diodes

Experimental responses of two different substrate thicknesses of SiC Junction-Barrier-Schottky (JBS) diodes are presented by Kr and Bi ions irradiation experiments. Three bias voltages of 250 V, 275 V, and 300 V were chosen to analyse single event leakage current (SELC) degradation and single event burnout (SEB) in the 650 V-rated devices with standard (350 μm) and thin (150 μm) substrates, respectively. Measured data indicate that under the same bias voltage and heavy ion parameter conditions, the degree of leakage degradation of the device is weaker for the SiC JBS with thin substrate structure. Measured data also indicate that when the device at a bias voltage of 300 V by the Bi-ion irradiation experiment, SEB occurred in the standard substrate device, but only leakage current degradation occurred in the thin substrate device. The weakening of effective charge deposition and impact ionization rate in thin-substrate devices are the main reasons for SELC degradation and SEB threshold increasing. Corresponding TCAD simulations are also utilized to analyse physical parameters and confirm the mechanism.

A Fast Simulation Method for Evaluating the Single-Event Effect in Aerospace Integrated Circuits.

With the continuous progress in integrated circuit technology, single-event effect (SEE) has become a key factor affecting the reliability of aerospace integrated circuits. Simulating fault injection using the computer simulation technique effectively reflects the SEE in aerospace integrated circuits. Due to various masking effects, only a small number of faults will result in errors; the traditional method of injecting one fault in one workload execution is inefficient. The method of injecting multiple faults in one workload execution will make it impossible to judge which fault results in errors because the propagation characteristic of SEE and faults may affect each other. This paper proposes an improved multi-point fault injection method to improve simulation efficiency and solve the problems of the general multi-point fault injection method. If one workload execution does not result in errors, multiple faults can be verified by one workload execution. If one workload execution results in errors, a specific grouping method can be used to determine which faults result in errors. The experimental results show that the proposed method achieves a good acceleration effect and significantly improves the simulation efficiency.

A comprehensive study of InGaAs based linearly graded channel DL-TFET and its single event transient effect

In this paper, the DC, RF and single-event transient effect studies are carried out for investigating the performance and reliability of hetero-junction InGaAs DL-TFET having linearly graded channel region. The mole-fraction of source side In1−xGaxAs is varied for obtaining the higher ION i.e. obtained at x = 0.40; this also impact the RF simulation studies by increasing the gain-bandwidth product range to 52.4 GHz. To reduce Iambipolar, a step junction is introduced for first time in the channel region at channel-drain interface which reduces the Iambipolar by 93.27% to the magnitude of 0.867 μA μm−1. Further reduction in ambipolarity is achieved at TG = 3.9 eV to the level of 0.269 fA μm−1, ION increases to 0.558 mA μm−1, sub-threshold swing is 23.8 mV/decade and shows highest cut-off frequency upto 155 GHz. Hence, the optimized device structure is investigated under the influence of single-event transient; therefore, the effect of heavy ion is investigated on optimized linearly graded structure for different LETs’ (Linear energy transfer). It shows increase in the drain current and charge collected with increase in LET. The maximum IDS is 0.618 mA μm−1 in OFF state, and IDS of 0.819 mA μm−1 in ON state at VDS = 1.0 V, which is higher than its ION at 10 MeV.cm2/mg (i.e. 0.11 pC μm−1). By simulating heavy ion single event effect on different positions, it is found that channel-drain interface is more sensitive to irradiation. This gives an insight for radiation hardened applications in space for TFET based circuit designs.

Impact of Back-Gate Radiation on Single-Event Effects of Ultrathin Body and Buried Oxide Fully Depleted Silicon-on-Insulator MOSFETs

Impact of Back-Gate Radiation on Single-Event Effects of Ultrathin Body and Buried Oxide Fully Depleted Silicon-on-Insulator MOSFETs

Sensitivity investigation of 100-MeV proton irradiation to SiGe HBT single event effect

The single event effect (SEE) sensitivity of silicon–germanium heterojunction bipolar transistor (SiGe HBT) irradiated by 100-MeV proton is investigated. The simulation results indicate that the most sensitive position of the SiGe HBT device is the emitter center, where the protons pass through the larger collector-substrate (CS) junction. Furthermore, in this work the experimental studies are also carried out by using 100-MeV proton. In order to consider the influence of temperature on SEE, both simulation and experiment are conducted at a temperature of 93 K. At a cryogenic temperature, the carrier mobility increases, which leads to higher transient current peaks, but the duration of the current decreases significantly. Notably, at the same proton flux, there is only one single event transient (SET) that occurs at 93 K. Thus, the radiation hard ability of the device increases at cryogenic temperatures. The simulation results are found to be qualitatively consistent with the experimental results of 100-MeV protons. To further evaluate the tolerance of the device, the influence of proton on SiGe HBT after gamma-ray (60Coγ) irradiation is investigated. As a result, as the cumulative dose increases, the introduction of traps results in a significant reduction in both the peak value and duration of the transient currents.

Single Event Upset Study of 22 nm Fully Depleted Silicon-on-Insulator Static Random Access Memory with Charge Sharing Effect.

In this paper, the single event effect of 6T-SRAM is simulated at circuit level and device level based on a 22 nm fully depleted silicon-on-insulator (FDSOI) process, and the effects of charge sharing and bipolar amplification are considered in device-level simulation. The results demonstrate that, under the combined influence of these two effects, the circuit's upset threshold and critical charge decreased by 15.4% and 23.5%, respectively. This indicates that the charge sharing effect exacerbates the single event effects. By analyzing the incident conditions of two different incident radius particles, it is concluded that the particles with a smaller incident radius have a worse impact on the SRAM circuit, and are more likely to cause the single event upset in the circuit, indicating that the ionization distribution generated by the incident particle affects the charge collection.

Single-event effect hardening of the Schottky contact super barrier rectifier (SSBR) with high-k gate dielectric

Single-event effect hardening of the Schottky contact super barrier rectifier (SSBR) with high-k gate dielectric

Investigation of the aberrant record from bus GPS receiver onboard FORMOSAT-7/COSMIC-2 satellite constellation in low Earth orbit

The FORMOSAT-7/COSMIC-2 (F7/C2) satellite constellation, a joint Taiwan-US collaboration mission, was launched on 25 June 2019. Following the FORMOSAT-3/COSMIC, the F7/C2 mission aims to provide global users the next-generation global navigation satellite system (GNSS) radio occultation data. The mission consists of six identical small satellites with an inclination angle of 24°, launched to the parking orbit of 720 km, and then transferred to the mission orbit of 550 km. Each satellite bus is equipped with two commercial off-the-shelf global positioning system receivers manufactured by Surrey Satellite Technology Ltd. for positioning, navigation, and timing functions. This receiver generates “GPS Receiver (bus GPSR) Warm Start Requested (WSR)” messages after commissioning, which could be considered as a kind of single event effect (SEE). More than 7000 WSR events have been recorded in 3 years after launch, providing another opportunity to investigate the SEE with the commercial off-the-shelf bus GPSR. In addition, the F7/C2 mission is the first satellite constellation that allows scientists to investigate the SEE using the same constellation at different altitudes of Low-Earth orbit. This study investigates and discusses the cumulative rate, distribution of WSRs, and their relationships between altitude and geomagnetic field. The statistical method is applied to define a warning area of the high probability occurring the SEE of this kind of component based on the geomagnetic field, whose corresponding strength is around 21,200/20,550 nT and close to the South Atlantic Anomaly area. Moreover, the relationships with space weather, including the disturbance of the Earth's magnetic field (Kp index) and the solar activity (F10.7 index), are also analyzed and reported.

Total ionizing dose effects of 60Co-γ ray radiation on SiC MOSFETs with different gate oxide thickness

The application of SiC power devices in the space radiation environment not only requires good resistance to Single Event Effect (SEE) but also requires certain resistance to Total Ionizing Dose (TID) and long-term reliability. Increasing the thickness of the gate oxide layer (tox) can effectively improve the ability of SiC VDMOS to resist SEE. However, it will mainly impact its resistance to TID and Gate Oxide Integrity (GOI). Therefore, this paper compares the influence of tox on the radiation resistance and long-term reliability of SiC VDMOS under the same process and irradiation conditions. The experimental results show that after being irradiated by Cobalt-60 γ-rays, the static parameters of SiC VDMOS devices degrade severely with the increase of the tox; at the same time, the thick gate oxide process will also cause more defects in the gate oxide, leading to the decrease of the gate oxide long-term reliability, but it can be significantly improved after high temperature (HT) accelerated annealing. The research results suggest that the method of increasing tox should take into account the requirements of TID resistance and long-term reliability when improving the SEE radiation resistance of SiC VDMOS. This study is based on the improvement of electrical parameters and the analysis of reliability degradation of SiC VDMOS, providing experimental data support for determining the balance point of tox.

Development of 400 V-Tolerant Single-Event Effect Hardened 4H-SiC Schottky Diode With Linear Energy Transfer Upto 83.5 MeV⋅cm2/mg

A novel 4H-SiC junction barrier Schottky (JBS) with deep linear graded doping (DLGD) P junction structure is proposed and fabricated to enhance the radiation tolerance of Single-Event Effect (SEE). The radiation-hardened function of the proposed new structure is confirmed via two-dimensional numerical simulation and SEE experiment. The hardened device was tested under heavy ion irradiation with linear energy transfer (LET) up to 83.5 MeV·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /mg. Test results show that the single-event leakage current (SELC) threshold voltage of the hardened device is 400 V, which is the best SEE radiation-hardened performance reported so far for high-voltage 4H-SiC JBS. Compared with the state-of-the-art counterparts, this work is about 2 times improvement in SELC threshold voltage.

Parametric Evaluation of the See Rate on the SEU and SEL Monitors Aboard the Alphasat Using the IRPP Model

Calculating Single Event Effect (SEE) rates is essential to ensure space mission reliability. Standard methods rely on ground-data which is not fully representative of the space radiation environment. In this paper, we evaluate these methods using SEE data collected during 5.5 years from the Single Event Upset and Single Event Latch-up Monitors aboard the Alphasat spacecraft in Geostationary orbit.

14 Years of In-Flight Experimental Data on CARMEN-MEX

This paper presents in-flight Single Event Effects (SEE), Total Ionizing Dose (TID) and Total Non-Ionizing Dose (TNID) data collected since 2008 by CNES with CARMEN-MEX experiment on board of various satellites placed in Low-Earth Orbit or Geostationary orbits.

Evaluation of Neutron Radiation Impact for 1200-V Class 4H-SiC MOSFET at Gate Switching Mode With TCAD Simulation

We evaluated and analyzed power SiC MOSFETs with gate switching mode during neutron irradiation with our commercial single event effect (SEE) Analyzer. Based on evaluation and analysis, we found i) difference of radiation robustness characteristics, ii) switching mode to be worse condition than non-switching (DC bias condition) mode for 1200 V rated SiC MOSFETs, and iii) temperature dependence with three manufactures’ SiC MOSFETs. In order to clarify the difference between the switching mode and non-switching mode effect, and between the electrical characteristics of the devices, we extracted device-related parameters through physical structure analysis and systematically investigated the cause of the difference by performing simulations with TCAD. As a result, we found that the distribution of electric field according to the gate structure and oxide thickness of SiC MOSFET affects to SiC MOSFET radiation robustness. It was also observed that one of the acceleration factors for increased cross section was higher temperature during irradiation test.

Smart-Redundancy With In Memory ECC Checking: Low-Power SEE-Resistant FPGA Architectures

In harsh environments, such as space, radiation, and charged particles cause single-event effects (SEEs), faults occurring randomly on any electronic component. These must be mitigated to ensure device functionality. Modern mitigation methods, such as triple modular redundancy (TMR), are very effective against single-event transients (SETs) but incur a minimum of 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> cost in the area. Single-event upsets (SEUs) affect sequential elements and are regularly repaired using memory scrubbing. Scrubbing is a slow serial process going through every memory word, looking for errors to repair. Scrubbing involves a nonnegligible amount of time before an error is detected, during which other events can occur and compromise the system. Field-programmable gate arrays (FPGAs) rely heavily on sequential elements to store their configuration; thus, FPGA’s SEU detection time is critical to ensuring design sustainability in harsh conditions. In this article, we propose an alternative mitigation method based on sensor integration and FPGA architecture modification, called smart-redundancy with in-memory error correction code checking (SRIMECCC). The sensors allow asynchronous SEU detection, reducing the time to detect by 57 250 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> on average and enabling local reconfiguration. Our method includes built-in dual redundancy that reduces the power consumption by 87% on average, benefiting embedded systems. SRIMECCC is also an area-efficient technique that saves 28% of total effective area compared to TMRed designs implemented in FPGAs.

Single-Event Effects on Commercial-Off-the-Shelf Edge-Processing Artificial Intelligence ASICs

Single-event effects test results are presented for heavy ions and high-energy protons on two commercial edge-processing artificial intelligence application-specific integrated circuits, particularly the Google Coral Accelerator Module, which employs a Google Coral Edge Tensor Processing Unit, and the Intel Neural Compute Stick 2, which employs the Intel Movidius Myriad X. The observed SEE signatures, probable causes within the devices, and single-event functional interrupt cross-sections are discussed. Ultimately, when SEUs or SEFIs are observed, there are negligible changes in the measured precision or accuracy of the algorithm, and rarely do the errors result in incorrect identification or classification.

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.

Dice Selection in Hybrid Microcircuits For Aerospace Applications

Hybrid Microcircuits which bring about miniaturization with better performance and reliability are ideally suited for application specific low volume production requirement of space missions. A large number of HMCs are used in every spacecraft. HMCs generally use passive components and interconnections in thick film form, and active devices (MOSFETs, Transistor and Diode dice) and monolithic ICs (as bare chips) bonded to a substrate. Environmental radiation threat to ICs and other active circuitry is one of the major causes of failures in HMCs. The ionizing radiation present in the Van Allen Belt penetrates the satellite resulting in the excitation of electrons in the semiconductor valence band to conduction band in the active circuit and can be trapped. Secondary photon radiation, which are generated due to slowing down of high energy particles also strike interior of the spacecraft. The total interaction of various charged particles and photons to the internal circuitry of HMC depends on mass, charge state, kinetic energy of the striking photon as well as on the mass, charge and density of the die structure internal to HMC. The MOS die is prone to failure due to total ionization dose as well as single event effects which in turn may cause HMC failure. HMCs for space applications are mostly characterized with die passivation and hermetically sealed packages for its inherent advantages. In spite of the advantages offered by hermetic sealing like reliability, radiation shielding, out gassing etc, the radiation hardened dice are preferred for realization of HMCs for space systems. A feasibility study is carried out for using MIL and Commercial grade dice in HMCs without compromising on reliability aspects. The layout design, die attachment process, testing and extensive qualification become important in HMC apart from hermetic sealing so as to avoid catastrophic failure. This article details the radiation phenomena and its effects on dice used in HMCs. The advantages of hermetically sealed packages and use of MIL/Commercial grade dice in HMCs along with various mitigation techniques to have reliable circuit meeting the desired performance in space environment are also presented.