scholarly journals Nano-structuring, surface and bulk modification with a focused helium ion beam

2012 ◽  
Vol 3 ◽  
pp. 579-585 ◽  
Author(s):  
Daniel Fox ◽  
Yanhui Chen ◽  
Colm C Faulkner ◽  
Hongzhou Zhang
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
High Dose ◽  
Modification Process ◽  
Dose Irradiation ◽  
Probe Size ◽  
Helium Ion ◽  
High Incidence ◽  
High Level ◽  
Irradiation Process

We investigate the ability of a focused helium ion beam to selectively modify and mill materials. The sub nanometer probe size of the helium ion microscope used provides lateral control not previously available for helium ion irradiation experiments. At high incidence angles the helium ions were found to remove surface material from a silicon lamella leaving the subsurface structure intact for further analysis. Surface roughness and contaminants were both reduced by the irradiation process. Fabrication is also realized with a high level of patterning acuity. Implantation of helium beneath the surface of the sample is visualized in cross section allowing direct observation of the extended effects of high dose irradiation. The effect of the irradiation on the crystal structure of the material is presented. Applications of the sample modification process are presented and further prospects discussed.

scholarly journals Strain/Damage in Crystalline Materials Bombarded by MeV Ions: Recrystallization of GaAs by High-Dose Irradiation

1984 ◽  
Vol 35 ◽  
Author(s):  
C. R. Wie ◽  
T. Vreeland ◽  
T. A. Tombrello
Keyword(s):  
Surface Layer ◽  
Energy Loss ◽  
Ion Irradiation ◽  
Stopping Power ◽  
High Dose ◽  
Double Crystal ◽  
Saturation Phenomenon ◽  
Nuclear Stopping ◽  
X Ray ◽  
Dose Irradiation

ABSTRACTMeV ion irradiation effects on semiconductor crystals, GaAs(100) and Si (111) and on an insulating crystal CaF2 (111) have been studied by the x-ray rocking curve technique using a double crystal x-ray diffractometer. The results on GaAs are particularly interesting. The strain developed by ion irradiation in the surface layers of GaAs (100) saturates to a certain level after a high dose irradiation (typically 1015/cm2), resulting in a uniform lattice spacing about 0.4% larger than the original spacing of the lattice planes parallel to the surface. The layer of uniform strain corresponds in depth to the region where electronic energy loss is dominant over nuclear collision energy loss. The saturated strain level is the same for both p-type and n-type GaAs. In the early stages of irradiation, the strain induced in the surface is shown to be proportional to the nuclear stopping power at the surface and is independent of electronic stopping power. The strain saturation phenomenon in GaAs is discussed in terms of point defect saturation in the surface layer.An isochronal (15 min.) annealing was done on the Cr-doped GaAs at temperatures between 200° C and 700° C. The intensity in the diffraction peak from the surface strained layer jumps at 200° C < T ≤ 300° C. The strain decreases gradually with temperature, approaching zero at T ≤ 500° C.The strain saturation phenomenon does not occur in the irradiated Si. The strain induced in Si is generally very low (less than 0.06%) and is interpreted to be mostly in the layers adjacent to the maximum nuclear stopping region, with zero strain in the surface layer. The data on CaF2 have been analysed with a kinematical x-ray diffraction theory to get quantitative strain and damage depth profiles for several different doses.

scholarly journals Stationary beam full-field transmission helium ion microscopy using sub-50 keV He+: Projected images and intensity patterns

2019 ◽  
Vol 10 ◽  
pp. 1648-1657
Author(s):  
Michael Mousley ◽  
Santhana Eswara ◽  
Olivier De Castro ◽  
Olivier Bouton ◽  
Nico Klingner ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Far Field ◽  
Ion Scattering ◽  
Full Field ◽  
Helium Ion ◽  
Powder Samples ◽  
Convergent Beam ◽  
Surface Diffraction ◽  
Possible Cause

A dedicated transmission helium ion microscope (THIM) for sub-50 keV helium has been constructed to investigate ion scattering processes and contrast mechanisms, aiding the development of new imaging and analysis modalities. Unlike a commercial helium ion microscope (HIM), the in-house built instrument allows full flexibility in experimental configuration. Here, we report projection imaging and intensity patterns obtained from powder and bulk crystalline samples using stationary broad-beam as well as convergent-beam illumination conditions in THIM. The He+ ions formed unexpected spot patterns in the far field for MgO, BN and NaCl powder samples, but not for Au-coated MgO. The origin of the spot patterns in these samples was investigated. Surface diffraction of ions was excluded as a possible cause because the recorded scattering angles do not correspond to the predicted Bragg angles. Complementary secondary electron (SE) imaging in the HIM revealed that these samples charge significantly under He+ ion irradiation. The spot patterns obtained in the THIM experiments are explained as artefacts related to sample charging. The results presented here indicate that factors other than channeling, blocking and surface diffraction of ions have an impact on the final intensity distribution in the far field. Hence, the different processes contributing to the final intensities will need to be understood in order to decouple and study the relevant ion-beam scattering and deflection phenomena.

Ion Beam Induced Intermixing of Wsi0.45 on GaAs

1988 ◽  
Vol 128 ◽  
Author(s):  
S. J. Pearton ◽  
K. T. Short ◽  
K. S. Jones ◽  
A. G. Baca ◽  
C. S. Wu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Ion Beam ◽  
Dose Range ◽  
Device Fabrication ◽  
Electrical Activation ◽  
High Dose ◽  
Dislocation Loops ◽  
Semiconductor Interface ◽  
High Level

ABSTRACTThe systematics of ion beam induced intermixing of WSi0.45 on GaAs have been studied after through-implantation of Si or O in the dose range 1013 − 5 × 1016 cm−2. SIMS profiling shows significant knock-on of Si and W into the GaAs at the high dose range in accordance with Monte Carlo simulations, but there is virtually no electrical activation (≤0.1%) of this Si after normal implant annealing (900°C, 10 sec). This appears to be a result of the high level of disorder near the metal-semiconductor interface, which is not repaired by annealing. This damage consists primarily of dislocation loops extending a few hundred angstroms below the end of range of the implanted ions. Extrapolation of the ion doses used in this work to the usual doses used in GaAs device fabrication would imply that ion-induced intermixing of WSix will not be significant in through-implantation processes.

The Effect of Thermal Spike on the Ion Irradiation Induced Grain Growth

1991 ◽  
Vol 235 ◽  
Author(s):  
K. H. Chae ◽  
J. H. Song ◽  
J. H. Joo ◽  
J. J. Woo ◽  
C. N. Whang ◽  
...  
Keyword(s):  
Grain Growth ◽  
Low Dose ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heat Of Mixing ◽  
High Dose ◽  
Thermal Spike ◽  
Close Relationship ◽  
Basic Parameters ◽  
Good Agreement

ABSTRACTThe relation between the ion irradiation induced grain growth in bilayer system and the basic parameters involved in ion beam mixing process was studied. TEM micrographs showed that a significant grain growth has been induced by Ar+ irradiation at room temperature. The grain size increases rapidly in low dose region, while it approaches a saturated value in high dose region, and it has close relationship with thermodynamic properties such as cohesive energy ( ΔHc ) and heat of mixing( ΔHm ). The experimental results are in good agreement with the model for the grain growth based on the thermal spike induced atomic migration.

scholarly journals Mixing of Al Into Uranium Silicides Reactor Fuels

1996 ◽  
Vol 439 ◽  
Author(s):  
Fu-Rong Ding ◽  
R. C. Birtcher ◽  
B. J. Kestel ◽  
P. M. Baldo
Keyword(s):  
Ion Beam ◽  
High Dose ◽  
Ion Beam Mixing ◽  
Dose Irradiation ◽  
Fuel Burn ◽  
Fission Gas ◽  
Mixing Rates ◽  
Radiation Induced ◽  
And Diffusion ◽  
Swelling Behaviors

AbstractSEM observations have shown that irradiation induced interaction of the aluminum cladding with uranium silicide reactor fuels strongly affects both fission gas and fuel swelling behaviors during fuel burn-up. We have used ion beam mixing, by 1.5 MeV Kr, to study this phenomena. RBS and the 27 A1( p, γ) 28 Si resonance nuclear reaction to was used to measure radiation induced mixing of Al into U3Si and U3Si2 after irradiation at 300γ;C.Initially U mixes into the Al layer and Al mixes into the U3 Si. At a low doses, the Al layer is converted into Ual4 type compound while near the interface the phase U(Al93 Si. 07 )3 grows. Under irradiation, Al diffuses out of the Ual4 surface layer, and the lower density ternary, which is stable under irradiation, is the final product. Al mixing into U3 Si2 is slower than in U3 Si, but after high dose irradiation the Al concentration extends much father into the bulk. In both systems Al mixing and diffusion is controlled by phase formation and growth. The Al mixing rates into the two alloys are similar to that of Al into pure uranium where similar aluminide phases are formed.

Radiation-Induced Nanostructures in an Iron Phosphate Glass

2003 ◽  
Vol 792 ◽  
Author(s):  
K. Sun ◽  
T. Ding ◽  
L.M. Wang ◽  
R.C. Ewing
Keyword(s):  
Phosphate Glass ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Dose Range ◽  
Iron Phosphate ◽  
High Energy ◽  
High Dose ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Feo Nanoparticles

ABSTRACTElectron and ion irradiation-induced nanostructures in an iron phosphate glass with a composition of 45 mol%Fe2O3-55 mol%P2O5 have been characterized by advanced electron microbeam techniques. Analysis by energy-filtered transmission electron microscopy indicated that Fe-rich and P-rich nanophases were formed when the glass was irradiated under a broad (with a diameter of 1.2μm) electron beam [give the dose range]. Phase separation developed with the increase in electron dose (from 1.0×1026e/m2 to 4.8×1026e/m2) as a result of the formation of an Fe-rich phase and pure P-phase. The formation of the Fe-rich and the P-phases are thought to be due to mainly ionization process. Under a low energy ion beam irradiation, Fe/FeO nanoparticles were formed, as confirmed by selected-area electron diffraction analysis. However, no nanoparticles were observed under a high-energy high-dose ion irradiation. The ion beam-irradiation results suggest that the formation of the Fe/FeO nanoparticles was due to preferential sputtering during ion irradiation and that the nanoparticles lie within the surface layers of the glass.

scholarly journals Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS2 field-effect transistors

2020 ◽  
Vol 11 ◽  
pp. 1329-1335
Author(s):  
Jakub Jadwiszczak ◽  
Pierce Maguire ◽  
Conor P Cullen ◽  
Georg S Duesberg ◽  
Hongzhou Zhang
Keyword(s):  
Field Effect ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Electrical Conductance ◽  
Charge Carrier Mobility ◽  
Electrical Performance ◽  
Transistor Channel ◽  
Helium Ion

Helium ion irradiation is a known method of tuning the electrical conductivity and charge carrier mobility of novel two-dimensional semiconductors. Here, we report a systematic study of the electrical performance of chemically synthesized monolayer molybdenum disulfide (MoS2) field-effect transistors irradiated with a focused helium ion beam as a function of increasing areal irradiation coverage. We determine an optimal coverage range of approx. 10%, which allows for the improvement of both the carrier mobility in the transistor channel and the electrical conductance of the MoS2, due to doping with ion beam-created sulfur vacancies. Larger areal irradiations introduce a higher concentration of scattering centers, hampering the electrical performance of the device. In addition, we find that irradiating the electrode–channel interface has a deleterious impact on charge transport when contrasted with irradiations confined only to the transistor channel.

Effects of High-Energy Carbon Ion Irradiation on Isatis Indigotica Fort

2011 ◽  
Vol 317-319 ◽  
pp. 2056-2062 ◽  
Author(s):  
Guang Liang Shi ◽  
Xue Hong Wang ◽  
Kai Guo ◽  
Zhao Zhou Li ◽  
Xiao Yan Hu ◽  
...  
Keyword(s):  
Soluble Protein ◽  
Selective Breeding ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Energy ◽  
Total Soluble Protein ◽  
High Dose ◽  
Isatis Indigotica ◽  
Carbon Ion ◽  
Different Doses

The aim of this study was to provide a theoretical basis for a high-energy carbon ion irradiation process for inducing mutations for selective breeding in Isatis indigotica Fort. The experiments were designed to evaluate the effects of different doses of high-energy 12C6+ ions (10-140 Gy) on physiological changes in I. indigotica seedlings. Dry seeds of I. indigotica were irradiated using different doses of 270 MeV energy 12C6+ ion beam, and the response of the subsequent seedlings was monitored using well-established indexes of physiological characteristics. Results showed that optimum results were achieved with a high-dose 12C6+ ion beam at 35 Gy where the activities of superoxide dismutase (SOD) and catalase (CAT) were enhanced. However, excessive irradiation reduced the activities of SOD and CAT. As the dose increased, the activity of peroxidase increased initially and then decreased compared with controls that were not irradiated (0 Gy). The content of malondialdehyde first decreased and then increased with the treatment. Total soluble protein content initially increased and then decreased with increasing doses of radiation; the proline content improved sharply compared to the control. The results of this study suggest that that a low dose of 12C6+ ion beam could enhance the activities of protective enzymes and the levels of proline and soluble protein, and that a dose range of 35–60 Gy is likely to be optimum for inducing useful mutations in I. indigotica for a stable selective breeding program.

Helium Ion Beam Induced Arsenic Atom Displacement Studied by Medium-Energy Ion Spectroscopy

1993 ◽  
Vol 316 ◽  
Author(s):  
Shin Yokoyama ◽  
Zbigniew J. Radzimski ◽  
Kensaku Ishibashi ◽  
Takeshi Watanabe ◽  
Masataka Hirose
Keyword(s):  
Low Dose ◽  
Ion Beam ◽  
High Dose ◽  
Medium Energy ◽  
Arsenic Atom ◽  
Ion Beam Irradiation ◽  
Nuclear Stopping ◽  
Ion Spectroscopy ◽  
Helium Ion ◽  
Atom Displacement

ABSTRACTAn arsenic atom displacement in As+ ion implanted Si induced by He+ ion beam irradiation has been studied by medium-energy (175keV) ion spectroscopy (MEIS). The He+ energy and dose dependences of the displaced arsenic atoms have been examined in the range of 30-175keV and ≤6×10-4C/cm2, respectively. The amount of the displaced arsenic atoms are found to be proportional to the dose and inversely proportional to the nuclear stopping power in the low-dose region, while it saturates at high-dose region. The dose-proportional region is composed of two different proportional coefficient segments.

Ion-beam induced disordering and onset of amorphization in spinel by defect accumulation

1995 ◽  
Vol 10 (4) ◽  
pp. 981-985 ◽  
Author(s):  
N. Bordes ◽  
L.M. Wang ◽  
R.C. Ewing ◽  
K.E. Sickafus
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Crystalline Material ◽  
High Dose ◽  
Transmission Electron ◽  
Defect Accumulation ◽  
Radiation Resistant ◽  
Crystalline Domains ◽  
Resistant Ceramic

Ion-irradiation induces amorphization in many intermetallics and ceramics, but spinel (MgAl2O4) is considered a “radiation resistant” ceramic. Spinel was irradiated with 1.5 MeV Kr+ at 20 K and observed in situ by transmission electron microscopy (TEM). The spinel remained crystalline to a high dose of 1 × 1016 ions/cm2, without any evidence of amorphization. Another spinel was preimplanted with Ne (400 keV and 50 keV). The microstructure revealed a still crystalline material with 8 nm interstitial loops. After irradiation with 1.5 MeV Kr+ (20 K), amorphization, a result of cation disordering, initiated at a dose of 1.7 × 1015 ions/cm2. At a dose of 1 × 1016 ions/cm2, the spinel was partially amorphous and the remaining crystalline domains disordered. These results show that spinel can be disordered and that amorphization can be triggered by the introduction of stable defects, followed by ion irradiation at low temperature.

Sign in / Sign up

Export Citation Format

Share Document