scholarly journals The Effect of Internal Free Surfaces on Void Swelling of Irradiated Pure Iron Containing Subsurface Trenches

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 252
Author(s):  
Tianyao Wang ◽  
Hyosim Kim ◽  
Frank A. Garner ◽  
Kenneth L. Peddicord ◽  
Lin Shao
Keyword(s):  
Pure Iron ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Full Range ◽  
Peak Displacement ◽  
Free Surfaces ◽  
Projected Range ◽  
Void Swelling ◽  
Displacement Per Atom

We studied the effects of internal free surfaces on the evolution of ion-induced void swelling in pure iron. The study was initially driven by the motivation to introduce a planar free-surface defect sink at depths that would remove the injected interstitial effect from ion irradiation, possibly enhancing swelling. Using the focused ion beam technique, deep trenches were created on a cross section of pure iron at various depths, so as to create bridges of thickness ranging from 0.88 μm to 1.70 μm. Samples were then irradiated with 3.5 MeV Fe2+ ions at 475 °C to a fluence corresponding to a peak displacement per atom dose of 150 dpa. The projected range of 3.5 MeV Fe2+ ions is about 1.2 μm so the chosen bridge thicknesses involved fractions of the ion range, thicknesses comparable to the mean ion range (peak of injected interstitial distribution), and thicknesses beyond the full range. It was found that introduction of such surfaces did not enhance swelling but actually decreased it, primarily because there were now two denuded zones with a combined stronger influence than that of the injected interstitial. The study suggests that such strong surface effects must be considered for ion irradiation studies of thin films or bridge-like structures.

scholarly journals Effect of Ion Irradiation on Nanoindentation Fracture and Deformation in Silicon Carbide

JOM ◽  
2021 ◽  
Author(s):  
Alexander J. Leide ◽  
Richard I. Todd ◽  
David E. J. Armstrong
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Compressive Residual Stresses

AbstractSilicon carbide is desirable for many nuclear applications, making it necessary to understand how it deforms after irradiation. Ion implantation combined with nanoindentation is commonly used to measure radiation-induced changes to mechanical properties; hardness and modulus can be calculated from load–displacement curves, and fracture toughness can be estimated from surface crack lengths. Further insight into indentation deformation and fracture is required to understand the observed changes to mechanical properties caused by irradiation. This paper investigates indentation deformation using high-resolution electron backscatter diffraction (HR-EBSD) and Raman spectroscopy. Significant differences exist after irradiation: fracture is suppressed by swelling-induced compressive residual stresses, and the plastically deformed region extends further from the indentation. During focused ion beam cross-sectioning, indentation cracks grow, and residual stresses are modified. The results clarify the mechanisms responsible for the modification of apparent hardness and apparent indentation toughness values caused by the compressive residual stresses in ion-implanted specimens.

scholarly journals Ion Irradiation-Induced Microstructural Evolution of Ni–Mo–Cr Low Alloy Steels

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2268
Author(s):  
Hongying Sun ◽  
Penghui Lei ◽  
Guang Ran ◽  
Hui Wang ◽  
Jiyun Zheng ◽  
...  
Keyword(s):  
Irradiation Dose ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Strength ◽  
Positron Annihilation Spectroscopy ◽  
Small Scale ◽  
Low Alloy Steels ◽  
Dislocation Loops ◽  
S Parameter

As leading candidates of sheet steels for advanced nuclear reactors, three types of Ni–Mo–Cr high-strength low alloy (HSLA) steels named as CNST1, CNST2 and CNSS3 were irradiated by 400 keV Fe+ with peak fluence to 1.4 × 1014, 3.5 × 1014 and 7.0 × 1014 ions/cm2, respectively. The distribution and morphology of the defects induced by the sample preparation method and Fe+ irradiation dose were investigated by transmission electron microscopy (TEM) and positron-annihilation spectroscopy (PAS). TEM samples were prepared with two methods, i.e., a focused ion beam (FIB) technique and the electroplating and twin-jet electropolishing (ETE) method. Point defects and dislocation loops were observed in CNST1, CNST2 and CNSS3 samples prepared via FIB. On the other hand, samples prepared via the ETE method revealed that a smaller number of defects was observed in CNST1, CNST2 and almost no defects were observed in CNST3. It is indicated that artifact defects could be introduced by FIB preparation. The PAS S-W plots showed that the existence of two types of defects after ion implantation included small-scale defects such as vacancies, vacancy clusters, dislocation loops and large-sized defects. The S parameter of irradiated steels showed a clear saturation in PAS response with increasing Fe+ dose. At the same irradiation dose, higher values of the S-parameter were achieved in CNST1 and CNST2 samples when compared to that in CNSS3 samples. The mechanism and evolution behavior of irradiation-induced defects were analyzed and discussed.

A Method for Site Specific Characterization Using a Dedicated FIB System Combined With an Analyitical TEM

1999 ◽  
Vol 5 (S2) ◽  
pp. 914-915
Author(s):  
T. Kamino ◽  
T. Yaguchi ◽  
H. Matsumoto ◽  
H. Kobayashi ◽  
H. Koike
Keyword(s):  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
System Stability ◽  
Specimen Preparation ◽  
Thin Specimen ◽  
Cross Sectional ◽  
Site Specific ◽  
Specimen Holder ◽  
High Resolution Tem

A method for site specific characterization of the materials using a dedicated focused ion beam(FIB) system and an analytical transmission electron microscope (TEM) was developed. Needless to say, in TEM specimen preparation using FIB system, stability of a specimen is quite important. The specimen stage employed in the developed FIB system is the one designed for high resolution TEM, and the specimen drift rate of the stage is less than lnm/min. In addition, FIB-TEM compatible specimen holder which allows milling of a specimen with the FIB system and observation of the specimen with the TEM without re-loading was developed. To obtain thin specimen from the area to be characterized correctly, confirmation of the area before final milling is needed. However, observation of cross sectional view in a FIB system is recommended because it causes damage by Ga ion irradiation. To solve this problem, we used a STEM unit as a viewer of FIB milled specimen.

scholarly journals Optimization of Pt-C Deposits by Cryo-FIBID: Substantial Growth Rate Increase and Quasi-Metallic Behaviour

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1906 ◽  
Author(s):  
Alba Salvador-Porroche ◽  
Soraya Sangiao ◽  
Patrick Philipp ◽  
Pilar Cea ◽  
José María De Teresa
Keyword(s):  
Growth Rate ◽  
Electrical Resistivity ◽  
Room Temperature ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Electrical Contacts ◽  
Condensation Temperature ◽  
Monte Carlo Code ◽  
Condensed Layer

The Focused Ion Beam Induced Deposition (FIBID) under cryogenic conditions (Cryo-FIBID) technique is based on obtaining a condensed layer of precursor molecules by cooling the substrate below the condensation temperature of the gaseous precursor material. This condensed layer is irradiated with ions according to a desired pattern and, subsequently, the substrate is heated above the precursor condensation temperature, revealing the deposits with the shape of the exposed pattern. In this contribution, the fast growth of Pt-C deposits by Cryo-FIBID is demonstrated. Here, we optimize various parameters of the process in order to obtain deposits with the lowest-possible electrical resistivity. Optimized ~30 nm-thick Pt-C deposits are obtained using ion irradiation area dose of 120 μC/cm2 at 30 kV. This finding represents a substantial increment in the growth rate when it is compared with deposits of the same thickness fabricated by standard FIBID at room temperature (40 times enhancement). The value of the electrical resistivity in optimized deposits (~4 × 104 µΩ cm) is suitable to perform electrical contacts to certain materials. As a proof of concept of the potential applications of this technology, a 100 µm × 100 µm pattern is carried out in only 43 s of ion exposure (area dose of 23 μC/cm2), to be compared with 2.5 h if grown by standard FIBID at room temperature. The ion trajectories and the deposit composition have been simulated using a binary-collision-approximation Monte Carlo code, providing a solid basis for the understanding of the experimental results.

Low Energy Focused Ion Beam Processing

1992 ◽  
Vol 279 ◽  
Author(s):  
Kenji Gamo
Keyword(s):  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Etching Rate ◽  
High Mobility ◽  
Low Energy ◽  
High Electron ◽  
Optimization Of Process Parameters ◽  
High Etching Rate

ABSTRACTFocused ion beam (FIB) techniques have many advantages which stem from being maskless and have attracted much interest for various applications includingin situprocessing. However, reduction of damage and improvement of throughput are problems awaiting solution. For reduction of damage, low energy FIB is promising and for improvement of throughput, understanding of the basic processes and optimization of process parameters based on this understanding is crucial. This paper discusses characteristics of low energy FIB system, ion beam assisted etching and ion implantation, and effect of damage with putting emphasize onin situfabrication. Low energy (0.05–25keV) FIB system being developed forms -lOOnm diameter ion beams and is connected with molecular beam epitaxy system. Many results indicate that low damage, maskless ion beam assisted etching is feasible using low energy beams. Recently it was also shown that for ion beam assisted etching of GaAs, pulse irradiation yields very high etching rate of 500/ion. This indicates that the optimization of the relative ratio of ion irradiation and reactant gas supply as important to achieve high etching rate. Low energy FIB is also important for selective doping for high electron mobility heterostructures of GaAs/GaAlAs, because high mobility is significantly degraded by a slight damage.

Three-Dimensional Analysis of Carbon Nanotube Networks in Interconnects by Electron Tomography without Missing Wedge Artifacts

2010 ◽  
Vol 16 (2) ◽  
pp. 210-217 ◽  
Author(s):  
Xiaoxing Ke ◽  
Sara Bals ◽  
Daire Cott ◽  
Thomas Hantschel ◽  
Hugo Bender ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Electron Tomography ◽  
Ion Beam ◽  
Full Range ◽  
Three Dimensional ◽  
X Ray ◽  
Quantitative Studies ◽  
Transmission Electron ◽  
Carbon Nanotube Networks ◽  
Semiconductor Contact

AbstractThe three-dimensional (3D) distribution of carbon nanotubes (CNTs) grown inside semiconductor contact holes is studied by electron tomography. The use of a specialized tomography holder results in an angular tilt range of ±90°, which means that the so-called “missing wedge” is absent. The transmission electron microscopy (TEM) sample for this purpose consists of a micropillar that is prepared by a dedicated procedure using the focused ion beam (FIB) but keeping the CNTs intact. The 3D results are combined with energy dispersive X-ray spectroscopy (EDS) to study the relation between the CNTs and the catalyst particles used during their growth. The reconstruction, based on the full range of tilt angles, is compared with a reconstruction where a missing wedge is present. This clearly illustates that the missing wedge will lead to an unreliable interpretation and will limit quantitative studies.

Method for Cross-sectional Transmission Electron Microscopy Specimen Preparation of Composite Materials Using a Dedicated Focused Ion Beam System

1999 ◽  
Vol 5 (5) ◽  
pp. 365-370 ◽  
Author(s):  
Toshie Yaguchi ◽  
Takeo Kamino ◽  
Tohru Ishitani ◽  
Ryoichi Urao
Keyword(s):  
Composite Materials ◽  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Implantation Rate ◽  
Specimen Preparation ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron ◽  
Lattice Images

A new method for transmission electron microscope (TEM) specimen preparation using a focused ion beam (FIB) system that results in a lower rate of gallium (Ga) implantation has been developed. The method was applied to structural and analytical studies of composite materials such as silicon (Si)-devices and magneto-optical disk. To protect the specimens against Ga ion irradiation, amorphous tungsten (W) was deposited on the surface of the specimen prior to FIB milling. The deposition was quite effective in reducing the Ga implantation rate, and energy-dispersive X-ray (EDX) analysis of these specimens detected 0.3Ð1.5% Ga incorporated in the thinned area. FIB milling times for these specimens were 1.5Ð2 hr. Although the milling rate was high, all the materials were properly prepared for TEM study, and clear crystal lattice images were observed on all specimens.

Local Modification of Microstructure and of Properties by FIB-CVD

2003 ◽  
Vol 792 ◽  
Author(s):  
H. Wanzenboeck ◽  
S. Harasek ◽  
H. Langfischer ◽  
B. Basnar ◽  
W. Brezna ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Beam Diameter ◽  
Energetic Ions ◽  
Microstructure Fabrication ◽  
Processed Material ◽  
Versatile Tool ◽  
Local Modification ◽  
Atomic Mixing

ABSTRACTThe focused ion beam has been acknowledged as a versatile tool for local sputtering as well as local deposition of material. A beam diameter below 10 nm is feasible and renders FIB a powerful tool for microstructure fabrication and generation. This experimental study investigates the geometrical limitations of FIB processing as well as the implications on the processed material. The high energetic ions of the primary beam also change the properties of the processed material due to implantation and atomic mixing. The incorporation of Ga from the FIB may be beneficial in the case of deliberate implantation or unfavorable as a chemical impurity. Higher doses of ion irradiation caused amorphisation of the material. The effects of FIB processing on the substrates as well as deposited structures are illustrated.

X-ray Topography of Strain Fields Induced by 100 MeV Ti7+ Ion Irradiated Si(100)

1995 ◽  
Vol 378 ◽  
Author(s):  
B. B. Sharma ◽  
S. R. Gupta ◽  
R. K. Sharma ◽  
V. Kumar ◽  
U. Tiwari ◽  
...  
Keyword(s):  
Plane Strain ◽  
Strain Field ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Lattice Deformation ◽  
Beam Direction ◽  
Strain Fields ◽  
X Ray ◽  
Projected Range ◽  
Out Of Plane

AbstractThe lattice deformation caused by 100 MeV Ti7+ ion irradiation in Si (100) has been studied using X-ray topographic techniques. An important finding is the appearance of a strain field perpendicular to the ion beam direction in the irradiated region well separated from the projected range of implanted ions. This in-plane strain extends in the bulk of the sample and is not merely confined to the surface. The implanted region has been found to experience an out of plane strain which is expected to be tensile in nature.

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