Displacement Damage Research Articles

Displacement Damage Effects on a CDTI-based CCD-on-CMOS: Dark Current and Charge Transfer Inefficiency

Displacement Damage Effects on a CDTI-based CCD-on-CMOS: Dark Current and Charge Transfer Inefficiency

Comparative study of collision cascades and resulting displacement damage in GaN, Si and Ge

Comparative study of collision cascades and resulting displacement damage in GaN, Si and Ge

Traumatic dentoalveolar fracture in a dog—An unusual and misdiagnosed injury

AbstractThe lateral luxation of a tooth is a traumatic dentoalveolar injury, which causes partial or complete tooth displacement and periodontal damage. We report a female mixed‐breed dog referred to the dentistry service with a lateral luxation of the maxillary left canine tooth due to a trauma‐related alveolar bone fracture. This unusual lesion is often misdiagnosed as a tooth fracture and potentially treated with extraction. Another major challenge is the need for emergency treatment since time decreases the number of periodontal ligament cells and hinders the pulp vascular supply. Without endodontic treatment, it may progress to pulp necrosis, root reabsorption and tooth loss. Instead of the classical treatment with a ligature wire, we performed a splint with acrylic resin, followed by root canal therapy and postoperative care. This technique was successful and spared the tooth, which remained structurally and periodontally sound and functional over 2 years of follow‐up.

Seismic response of reinforced concrete buildings, considering the effective stiffness in beams, columns and structural walls

The Peruvian Technical Standard E.030 for Seismic Resistant Design allows the analysis of the elastic range of buildings, considering gross stiffness. However, Peruvian Standard E060 considers the effects of axial loads, cracked regions in structural elements, and load duration. This research focuses on the impact of incorporating effective stiffness in seismic responses (displacements, drifts, and vibration periods) for six, seven, and eight-story reinforced concrete structures. The study quantifies the increase in seismic responses for design earthquakes and suggests that using effective stiffness in elastic analyses can reduce structural damage. To analyze seismic responses, three buildings of different heights were selected, meeting drift limits established by Standard E.030 using the gross section. Subsequently, twelve structural cases and combinations were created and analyzed in the ETABS program, employing the CQC criterion allowed by Standard E030. Different combinations of effective moment of inertia values for elastic analyses, according to ACI 318 (2014), were used. The study found that the simultaneous reduction of gross inertias of columns, beams, and structural walls led to a 1.2-fold increase in period and a 1.5-fold increase in drift, with variations based on the building's height. In conclusion, it is recommended to consider effective stiffness in elastic structural analyses to minimize displacement damage and ensure better structural performance during severe seismic events.

Nano-indentation deformation behavior of heavy ion irradiated reduced activation ferritic/martensitic (RAFM) steels

The Nano-indentation deformation behavior of the heavy ion irradiated RAFMs is investigated in the present work. Specimens of the CLF-1 steel were irradiated with 123.4 MeV 20Ne ion at both -50 °C and 400 °C, respectively, to achieve a mean displacement damage level of 0.15 dpa. A quasi-uniform distribution of the displacement damage was produced in the specimens by utilizing an energy degrader at the irradiation chamber. The results of nano-indentation experiments indicate that during the loading stage, the irradiated materials exhibit a lower strain rate, but during the holding stage after reaching the maximum load, the irradiated materials show a higher strain rate than the un-irradiated material. Transmission electron microscopy observation showed that the low-temperature irradiation produced a high density of irradiation-induced dislocation loops, which impeded the glide of dislocation lines during the loading stage. However, as the load increases gradually to the holding stage, the dislocation lines can overcome the pinning by the dislocation loops. The strain that did not occur due to the pinned effect of the dislocation loops in the loading stage was released during the holding stage, resulting in a higher strain rate in the irradiated specimen during the holding stage. Based on the Peierls mechanism, a quantitative relationship between the number density of the irradiation-induced dislocation loops and the strain rate during the holding stage was established. The calculated results agree well with the experimentally obtained strain rate during the holding stage.

Study of Single-Event Effects Influenced by Displacement Damage Effects under Proton Irradiation in Static Random-Access Memory

Static random-access memory (SRAM), a pivotal component in integrated circuits, finds extensive applications and remains a focal point in the global research on single-event effects (SEEs). Prolonged exposure to irradiation, particularly the displacement damage effect (DD) induced by high-energy protons, poses a substantial threat to the performance of electronic devices. Additionally, the impact of proton displacement damage effects on the performance of a six-transistor SRAM with an asymmetric structure is not well understood. In this paper, we conducted an analysis of the impact and regularities of DD on the upset cross-sections of SRAM and simulated the single-event upset (SEU) characteristics of SRAM using the Monte Carlo method. The research findings reveal an overall increasing trend in upset cross-sections with the augmentation of proton energy. Notably, the effect of proton irradiation on the SEU cross-section is related to the storage state of SRAM. Due to the asymmetry in the distribution of sensitive regions during the storage of “0” and “1”, the impact of DD in the two initial states is not uniform. These findings can be used to identify the causes of SEU in memory devices.

Evolution of Irradiation Defects in W and W-Re Systems: A Density Functional Theory and Rate Theory Study

In a fusion environment, tungsten, a plasma-facing material in a reactor, is subject to the irradiation of high-energy neutrons, generating a large amount of displacement damage and transmutation products (such as rhenium, Re). We studied the evolution of defects under irradiation in W and W-Re systems using the density functional theory (DFT) and rate theory (RT) method. The results indicate that the evolution of irradiation defects is mainly affected by the irradiation dose, dose rate, and temperature. During irradiation, loops form first in W, followed by the generation of voids, which are due to the different migration energies of point defects. Higher dose rates result in a higher density and larger size of defects in tungsten. Higher temperatures cause a decrease in void density and an increase in size. The results obtained at 600 °C were in good agreement with the reported TEM data. In W-Re alloys, it is indicated that the formation of loops is delayed because Re suppresses the nucleation of loops. The dynamic introduction of Re in W stabilizes the growth of defects compared to W-Re alloys, suggesting that transmuting elements have less detrimental effects on irradiation than alloying. As defect densities and sizes were quantified under different irradiation conditions, the results provide data for the multi-scale simulation of the radiation damage and thermal/mechanical properties in plasma-facing materials under fusion conditions.

Study of irradiation-induced vacancy-type defects in tungsten using positron annihilation spectroscopy

Tungsten has been considered as a potential candidate material for the application of plasma-facing components in magnetic confinement fusion reactors. Fusion neutrons introduce severe displacement damage into the first-wall materials along with a high amount of helium which is detrimental to the desirable material properties. Ion beam implantation combined with positron annihilation spectroscopy is a well-adopted method to investigate the irradiation damage in materials without any induced radioactivity. In this study, two separate tungsten samples were individually irradiated with 9.1 MeV Au5+ ions to a dose of 2.5 × 1014 ions/cm2 and 130 keV He ions to a dose of 1 × 1016 ions/cm2 with the intention to investigate the evolution of vacancy-type defects in the absence and presence of helium. The irradiated samples were subjected to isochronal annealing and characterized using positron annihilation Doppler broadening spectroscopy. The evolution of vacancy-type defects during different stages of annealing was investigated using defect-sensitive positron S-parameter. An increase in S-parameter due to the presence of vacancy-type defects was observed upon irradiation in both samples. The S-parameter variations with respect to the temperature showed different stages of vacancy annealing corresponding to stage III from 473 K to 673 K where the migration and clustering of mono-vacancies occurs, stage IV from 673 K to 973 K due to the growth of nano-voids and stage V from 973 K to 1273 K due to the dissociation of nano-voids. Complete recovery of irradiation-induced defects occurred in both samples at 1273 K. Both the samples showed similar vacancy annealing stages and no signature on the formation and growth of He-vacancy clusters or He bubbles was observed in the present study.

Influence of Temperature and Incidence Angle on the Irradiation Cascade Effect of 6H-SiC: Molecular Dynamics Simulations.

SiC devices have been typically subjected to extreme environments and complex stresses during operation, such as intense radiation and large diurnal amplitude differences on the lunar surface. Radiation displacement damage may lead to degradation or failure of the performance of semiconductor devices. In this paper, the effects of temperature and incidence angle on the irradiation cascade effect of 6H-SiC were investigated separately using the principles of molecular dynamics. Temperatures were set to 100 K, 150 K, 200 K, 250 K, 300 K, 350 K, 400 K and 450 K. The incidence direction was parallel to the specified crystal plane, with angles of 8°, 15°, 30°, 45°, 60° and 75° to the negative direction of the Z-axis. In this paper, the six types of defects were counted, and the microscopic distribution images and trajectories of each type of defect were extracted. The results show a linear relationship between the peak of the Frenkel pair and temperature. The recombination rate of Frenkel pairs depends on the local temperature and degree of aggregation at the center of the cascade collision. Increasing the angle of incidence first inhibits and then promotes the production of total defects and Frenkel pairs. The lowest number of total defects, Frenkel pairs and antisite defects are produced at a 45° incident angle. At an incidence angle of 75°, larger size hollow clusters and anti-clusters are more likely to appear in the 6H-SiC.

Peridynamic simulation of crashworthiness test of a tapered laminate under compressive loading

This study presents a peridynamic (PD) model to study the crashworthiness of a tapered laminate under compression. Along with a special explicit solution procedure to achieve the quasi-static response, a contact model is employed for load introduction from the rigid wall motion. Progressive damage is predicted by considering different bond types in the model. The validity of the approach is examined through comparison of the load vs displacement response and damage patterns with the experimental results. The PD simulations effectively capture different failure modes due to compressive loading until the laminate fully crashes. The predictions are consistent with the experimentally observations.

Study on post-fire resistance of ceramsite foamed concrete sandwich composite slabs

The ceramsite foamed concrete sandwich composite slab has the characteristics of light weight and good heat insulation performance. At present, there are few research on the fire resistance of ceramsite foamed concrete sandwich composite slab at home and abroad, and the damage mechanism of ceramsite foamed concrete sandwich composite slab under fire is not clear. To fill this gap, constant load-temperature rise fire test and static loading test on five slab specimens are conducted by varying the parameters such as sandwich layer thickness, reinforcement pattern, shear span ratio and construction method. Based on the test, the results are studied, including the temperature distribution and deformation characteristics under fire, load–displacement curves, crack pattern and damage mode, residual bearing capacity of the slab after fire. The results show that ceramsite foamed concrete sandwich composite slab has good thermal insulation performance, the overall working performance, flexural bearing capacity and deformation ability of the slab is mainly affected by the slip at the composite surface. The integrity of the slab and the residual bearing capacity and ductility after fire could be significantly improved by the configuration of truss rebar. It is suggested to decrease the time difference of concrete placement at the composite surface or set shear keys and truss rebar to improve the cooperative working ability between the surface layer and the sandwich layer. Moreover, Finite Element analysis is carried out by ABAQUS software and the results show good agreement with experiment results. A new compositeness degree analysis (CDA) method for calculating the residual bearing capacity of ceramsite foamed concrete sandwich composite slab after fire considering different compositeness degree is proposed, which could be used for the practical engineering design.

Application of displacement damage dose approach to low-energy proton irradiated GaInP/GaAs/Ge solar cells

In this paper, a displacement damage simulation model for proton-irradiated GaInP/GaAs/Ge triple junction (TJ) solar cells is constructed in Geant4, and the problem of the displacement damage dose curve deviation for low-energy protons is analyzed. The modeling results show that energy loss effects and local displacement damage are important factors for the deviation of the displacement damage dose curve. The non-ionizing energy loss (NIEL) values of GaAs sub-cells calculated by Geant4 can effectively improve the deviation of the curve caused by energy loss effects. The NIEL should be constrained by the structure and size of the device rather than just the proton energy and material type. In addition, the isotropic radiation field numerical method proposed in this paper allows the displacement damage simulation model constructed in Geant4 to be expediently applied to the radiation environment in space.

Study of displacement damage effects in InGaAs PIN photodiode under 10 MeV proton irradiation

The displacement damage effect of 10 MeV proton radiation on a high-speed InGaAs PIN photodiode has been experimentally investigated to evaluate the stability of the device in a space radiation environment. The results show that the dark current and low-frequency noise of the device increase significantly after irradiation, while the capacitance of the device decreases slightly after irradiation, where the spectral response parameters are less affected by irradiation. The increase in dark current is essentially linear with the displacement damage dose. Finally, the effect of proton irradiation on the optical communication system is simulated and the results show that the bit error rate of the system increases with the increase in irradiation fluence, which seriously affects the sensitivity of the optical communication system.

High-Energy Radiation Effects on Silicon NPN Bipolar Transistor Electrical Performance: A Study with 1 MeV Proton Irradiation.

This study investigates the degradation of the silicon NPN transistor's emitter-base junction, specifically the 2N2219A model, under both forward and reverse polarization. We examine the current-voltage characteristics under the influence of 1 MeV proton irradiation at various fluencies, which are 5.3×108,5.3×1010,5×1011,5×1012, and 5×1013 protons/cm², all conducted at 307 K. The experimental findings elucidate a pronounced dependency of diode parameters, including the reverse saturation current, series resistance, and the non-idealist factor, on the incident proton flow. This observation underscores that proton-induced degradation is primarily driven by displacement damage, while recorded degradation is predominantly attributed to the generation of defects and interfacial traps within the transistor resulting from exposure to high-energy radiation. Our findings indicate that the effects of irradiation align more closely with the compensation phenomenon in doping rather than its reinforcement.

On the use of SRIM for calculating arc-dpa exposure

We propose two methods for evaluating athermal recombination corrected (arc) displacement damage parameters in ion irradiations employing the computer code SRIM (Stopping and Range of Ions in Matter). The first method consists of post-processing the detailed SRIM output for all simulated damage events and re-calculating according to the arc damage model. In the second method, an approximate empirical formula is devised which gives the average displacements in the arc damage model as a function of the corresponding quantity according to the standard Norgett–Robinson–Torrens model, which is readily obtained from SRIM.

Predicting displacement damage for ion irradiation: Origin of the overestimation of vacancy production in SRIM full-cascade calculations

Ion irradiation and implantation have wide applications that demand accurate determination of displacement damage profile and distribution of implanted ion concentration. The prediction of vacancies is especially important to determine displacements per atom (dpa), the standard parameter of primary radiation damage in materials. However, significant discrepancies exist in estimations of vacancies between full-cascade (F-C) and quick calculation (Q-C) options in the popular computer code SRIM. This study inspected the SRIM code and a relatively new code called Iradina, which uses a similar methodology, to develop an understanding of the origin of vacancy overestimation in the F-C options for SRIM and Iradina. We found that the default values of thresholds (namely final energy in SRIM and replacement energy in Iradina) in displacement production calculations results in excessively large number of calculated vacancies and very few replacements. After conducting multiple calculations using SRIM, Iradina, and MARLOWE (all based on the binary collision approximation), a comparison of the results indicates that there is a shortcoming in the SRIM and Iradina F-C methodology for treating near-threshold collisions. This issue is responsible for the deficiency of replacements and excess of calculated vacancies in the SRIM and Iradina F-C results. Drawing on the principles of collision physics, we propose recommendations for modifying the source codes to address these issues.

Proton Irradiation‐Induced Displacement Damage in 650 V Si and SiC Power Diodes

A comparison of the displacement damage effects in Si and silicon carbide (4H‐SiC) commercial diodes due to 6 MeV proton irradiation is presented. The devices chosen for this study are rated at 650 V/8 A, making them technological alternatives of each other. It is found that Si diodes degrade ≈4.6 times faster than the SiC counterparts under forward biasing. In addition, the leakage current for the SiC diode in reverse mode decreases due to proton irradiation, whereas it increases for the Si diode under the same conditions. The difference in the behavior of both the diodes, as a result of the irradiation process, is discussed in terms of the induced deep‐level defects. The results show that SiC diodes are more resistant to displacement damage caused by proton irradiation than Si devices, with the same specifications.

Nanoscale imaging of He-ion irradiation effects on amorphous TaOx toward electroforming-free neuromorphic functions

Resistive switching in thin films has been widely studied in a broad range of materials. Yet, the mechanisms behind electroresistive switching have been persistently difficult to decipher and control, in part due to their non-equilibrium nature. Here, we demonstrate new experimental approaches that can probe resistive switching phenomena, utilizing amorphous TaOx as a model material system. Specifically, we applied scanning microwave impedance microscopy and cathodoluminescence (CL) microscopy as direct probes of conductance and electronic structure, respectively. These methods provide direct evidence of the electronic state of TaOx despite its amorphous nature. For example, CL identifies characteristic impurity levels in TaOx, in agreement with first principles calculations. We applied these methods to investigate He-ion-beam irradiation as a path to activate conductivity of materials and enable electroforming-free control over resistive switching. However, we find that even though He-ions begin to modify the nature of bonds even at the lowest doses, the films' conductive properties exhibit remarkable stability with large displacement damage and they are driven to metallic states only at the limit of structural decomposition. Finally, we show that electroforming in a nanoscale junction can be carried out with a dissipated power of <20 nW, a much smaller value compared to earlier studies and one that minimizes irreversible structural modifications of the films. The multimodal approach described here provides a new framework toward the theory/experiment guided design and optimization of electroresistive materials.

Effects of Fast Neutron Irradiation on Switching of Silicon Bipolar Junction Transistor

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly.Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs.Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively.Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

Orientation selected micro-pillar compression behavior of heavy-ions irradiated RAFMs

The present study aimed to investigate the mechanical property of heavy ions irradiated Reduced Activation Ferrite/Martensitic (RAFM) steels. The CLF-1 steel was irradiated by 33.5 MeV Fe ions at room temperature, resulting a peak displacement damage of 20 displacements per atom (dpa). Experimental analysis was conducted using Electron Backscatter Diffraction (EBSD) mapping-assisted Focused Ion Beam (FIB) technique to prepare micro-pillars oriented along crystal directions <0 0 1>. Subsequently, these fabricated micro-pillars underwent compression tests utilizing a flat indenter within the Nano-indentation setup. Engineering Stress-strain curves were generated for specimens both un-irradiated and irradiated. The yield strength of the un-irradiated and irradiated specimens in the <0 0 1> directions was determined by using the engineering stress-strain curves. In addition, the critical resolved shear stress (CRSS) of the un-irradiated and irradiated specimens was calculated. Microstructural analysis revealed that the formation of dense and fine dislocation loops were appeared in the material after irradiation. By combining the results of microstructure analysis with the dispersion barrier hardening model, the changes in CRSS caused by irradiation were calculated. Furthermore, the number of dislocation lines participating in deformation at a strain of 20 % was quantified, with the irradiated specimen exhibiting an increase of 33 % in comparison to the un-irradiated specimen.