Dynamic investigation of defects induced by short, high current pulses of high energy lithium ions

2014 ◽  
Vol 1712 ◽  
Author(s):  
Hua Guo ◽  
Arun Persaud ◽  
Steve Lidia ◽  
Andrew M. Minor ◽  
P. Hosemann ◽  
...  

ABSTRACTWe employ intense and short pulses of energetic lithium (Li+) ions to investigate the relaxation dynamics of radiation induced defects in single crystal silicon samples. Ions both create damage and track damage evolution simultaneously at short time scales when we use the channeling effect as a diagnostic tool. Ion pulses, ∼20 to 600 ns long and with peak currents of up to ∼1 A are formed in an induction type linear accelerator, the Neutralized Drift Compression eXperiment at Lawrence Berkeley National Laboratory. By rotating silicon (<100>) membranes of different thicknesses and changing the incident ion energy, the fraction of channeled ions in the transmitted beam could be varied. In preliminary experiments we find that the Li ion intensity is not high enough to generate overlapping cascades (in time and space) that would be necessary to measure a change in the shape of the current waveform of the transmitted ion beam. We discuss the concept of pump-probe type experiments with short ion beam pulses to access defect dynamics in materials and outline a path to increasing damage rates with heavier ions and by the application of longitudinal and lateral pulse compression techniques.

Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.


2020 ◽  
Vol 40 (12) ◽  
pp. 1222001
Author(s):  
宋辞 Song Ci ◽  
田野 Tian Ye ◽  
石峰 Shi Feng ◽  
张坤 Zhang Kun ◽  
沈永祥 Shen Yongxiang

1984 ◽  
Vol 35 ◽  
Author(s):  
J. O. Olowolafe ◽  
R. Fastow

ABSTRACTThin layers (~1,000 A ) of Ni and Co have been reacted with both (100) and amorphous silicon (a-Si) using a pulsed ion beam. Samples were analyzed using Rutherford backscattering, x-ray diffraction, and transmission electron microscopy. Rutherford backscattering showed that the metal/a-Si and metal/(100)-Si reaction rates were comparable. Both reactions began at the composition of the lowest eutectic. For comparison. furnace annealing of the same structures showed that the reaction rate of Ni with amorphous silicon was greater than with (100) Si; Co reacted nearly identically with both substrates. Diffraction data suggest that pulsed ion beam annealing crystallizes the amorphous silicon before the metal/a-Si reaction begins.


Author(s):  
V. S. Kovivchak ◽  
T. V. Panova ◽  
O. V. Krivozubov ◽  
N. A. Davletkil’deev ◽  
E. V. Knyazev

2005 ◽  
Vol 297-300 ◽  
pp. 292-298 ◽  
Author(s):  
Satoru Koyama ◽  
Kazuki Takashima ◽  
Yakichi Higo

Reliability is one of the most critical issues for designing practical MEMS devices. In particular, the fracture toughness of micro-sized MEMS elements is important, as micro/nano-sized flaws can act as a crack initiation sites to cause failure of such devices. Existing MEMS devices commonly use single crystal silicon. Fracture toughness testing upon micro-sized single crystal silicon was therefore carried out to examine whether a fracture toughness measurement technique, based upon the ASTM standard, is applicable to 1/1000th sized silicon specimens. Notched cantilever beam type specimens were prepared by focused ion beam machining. Two specimens types with different notch orientations were prepared. The notch plane/direction were (100)/[010], and (110)/[ _ ,110], respectively. Fracture toughness tests were carried out using a mechanical testing machine for micro-sized specimens. Fracture has been seen to occur in a brittle manner in both orientations. The provisional fracture toughness values (KQ) are 1.05MPam1/2 and 0.96MPam1/2, respectively. These values meet the micro-yielding criteria for plane strain fracture toughness values (KIC). Fracture toughness values for the orientations tested are of the same order as values in the literature. The results obtained in this investigation indicate that the fracture toughness measurement method used is applicable for micro-sized components of single crystal silicon in MEMS devices.


2006 ◽  
Vol 960 ◽  
Author(s):  
Warren MoberlyChan

ABSTRACTIon beams have been used to modify surface topography, producing nanometer-scale modulations (and even subnanometer ripples in this work) that have potential uses ranging from designing self-assembly structures, to controlling stiction of micromachined surfaces, to providing imprint templates for patterned media. Modern computer-controlled Focused Ion Beam tools enable alternating submicron patterned zones of such ion-eroded surfaces, as well as dramatically increasing the rate of ion beam processing. The DualBeam FIB/SEM also expedites process development while minimizing the use of materials that may be precious (Diamond) and/or produce hazardous byproducts (Beryllium). A FIB engineer can prototype a 3-by-3-by-3 matrix of variables in tens of minutes and consume as little as zeptoliters of material; whereas traditional ion beam processing would require tens of days and tens of precious wafers. Saturation wavelengths have been reported for ripples on materials such as single crystal silicon or diamond (∼200nm); however this work achieves wavelengths >400nm on natural diamond. Conversely, Be can provide a stable and ordered 2-dimensional array of <40nm periodicity. Also ripples <0.4nm are fabricated on carbon-base surfaces, and these quantized picostructures are measured by HR-TEM and electron diffraction. Rippling is a function of material, ion beam, and angle; but is also controlled by chemical environment, redeposition, and aspect ratio. Ideally a material has a constant yield (atoms sputtered off per incident ion); however, pragmatic FIB processes, coupled with the direct metrological feedback in a DualBeam tool, reveal etch rates do not remain constant for nanometer-scale processing. Control of rippling requires controlled metrology, and robust software tools are developed to enhance metrology. In situ monitoring of the influence of aspect ratio and redeposition at the micron scale correlates to the rippling fundamentals that occur at the nanometer scale and are controlled by the boundary conditions of FIB processing.


Author(s):  
R. C. Birtcher ◽  
L. M. Wang ◽  
C. W. Allen ◽  
R. C. Ewing

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Dongfang Zhang ◽  
Tobias Kroh ◽  
Felix Ritzkowsky ◽  
Timm Rohwer ◽  
Moein Fakhari ◽  
...  

Terahertz- (THz-) based electron manipulation has recently been shown to hold tremendous promise as a technology for manipulating and driving the next generation of compact ultrafast electron sources. Here, we demonstrate an ultrafast electron diffractometer with THz-driven pulse compression. The electron bunches from a conventional DC gun are compressed by a factor of 10 and reach a duration of ~180 fs (FWHM) with 10,000 electrons/pulse at a 1 kHz repetition rate. The resulting ultrafast electron source is used in a proof-of-principle experiment to probe the photoinduced dynamics of single-crystal silicon. The THz-compressed electron beams produce high-quality diffraction patterns and enable the observation of the ultrafast structural dynamics with improved time resolution. These results validate the maturity of THz-driven ultrafast electron sources for use in precision applications.


1984 ◽  
Vol 37 ◽  
Author(s):  
L. M. Mercandalli ◽  
D. Pribat ◽  
M. Dupuy ◽  
C. Arnodo ◽  
D. Rondi ◽  
...  

Astract(100) single crystal silicon films have been deposited onto (100) oriented Yttria-Stabilized Zirconia (YSZ) substrates by pyrolysis of SiH4 at ∼ 980°C.The as deposited epitaxial silicon films have been characterized by Reflexion High Energy Electron Diffraction and Transmission Electron Microscopy techniques.The as deposited silicon films have also been oxidized by oxygen transport through the substrate, resulting in a Si(100)/ amorphous SiO2/YSZ(100) structure in which the most defective part of the epitaxial silicon deposit has been eliminated. The oxidized interfaces (with SiO2 thicknesses in the 2000 Å range) have then been characterized by Transmission Electron Microscopy in order to assess the improvement in crystalline quality. Electrical measurements have also been performed on MOS-Hall bar structures.


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