High-fluence hyperthermal ion irradiation of gallium nitride surfaces at elevated temperatures

2014 ◽  
Vol 317 ◽  
pp. 811-817 ◽  
Author(s):  
A. Finzel ◽  
J.W. Gerlach ◽  
J. Lorbeer ◽  
F. Frost ◽  
B. Rauschenbach
Keyword(s):  
Gallium Nitride ◽  
Elevated Temperatures ◽  
Ion Irradiation ◽  
High Fluence

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

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.

scholarly journals The Potential of High-Fluence Ion Irradiation for Processing and Recovery of Diamond Tools

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1243
Author(s):  
Anatoly M. Borisov ◽  
Valery A. Kazakov ◽  
Eugenia S. Mashkova ◽  
Mikhail A. Ovchinnikov ◽  
Sergey N. Grigoriev ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ion Irradiation ◽  
Diamond Structure ◽  
High Fluence ◽  
Carbon Ions ◽  
Atomic Force ◽  
Synthetic Diamonds ◽  
Argon Ions ◽  
20 Nm ◽  
Scanning Electron

The graphitization and surface growth of synthetic diamonds by high-fluence irradiation with 30 keV argon and carbon ions have been experimentally studied. scanning electron microscope (SEM) and atomic force microscope (AFM) show removal of traces of mechanical polishing. The ion-induced roughness does not exceed 20 nm. Raman spectroscopy and the measurement of electrical conductivity confirm the graphitization of the surface layer when irradiated with argon ions at the temperature of 230 °C and the diamond structure of the synthesized layer when irradiated with carbon ions at the temperature of 650 °C.

scholarly journals Morphology modification of Si nanopillars under ion irradiation at elevated temperatures: plastic deformation and controlled thinning to 10 nm

2019 ◽  
Vol 35 (1) ◽  
pp. 015021 ◽  
Author(s):  
Xiaomo Xu ◽  
Karl-Heinz Heinig ◽  
Wolfhard Möller ◽  
Hans-Jürgen Engelmann ◽  
Nico Klingner ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Morphology Modification

Grain growth of nanocrystalline 3C-SiC under Au ion irradiation at elevated temperatures

2015 ◽  
Vol 49 (3) ◽  
pp. 035304 ◽  
Author(s):  
Limin Zhang ◽  
Weilin Jiang ◽  
Amila Dissanayake ◽  
Tamas Varga ◽  
Jiandong Zhang ◽  
...  
Keyword(s):  
Grain Growth ◽  
Elevated Temperatures ◽  
Ion Irradiation

Radiation Effects in Nonmetals: Amorphization, Phase Decomposition, and Nanoparticles

1998 ◽  
Vol 540 ◽  
Author(s):  
A. Meldrum ◽  
L.A. Boatner ◽  
C.W. White ◽  
D.O. Henderson
Keyword(s):  
Ion Implantation ◽  
Electron Irradiation ◽  
Radiation Effects ◽  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Semiconductor Nanocrystals ◽  
Heavy Ion ◽  
Fused Silica ◽  
Near Surface

AbstractRadiation effects in nonmetals have been studied for well over a century by geologists, mineralogists, physicists, and materials scientists. The present work focuses on recent results of investigations of the ion-beam-induced amorphization of the ABO4 compounds – including the orthophosphates (LnPO4; Ln = lanthanides) and the orthosilicates: zircon (ZrSiO4), hafnon (HfSiO4), and thorite (ThSiO4). In the case of the orthosilicates, heavy-ion irradiation at elevated temperatures causes the precipitation of a nanocrystalline metal oxide. Electron irradiation effects in these amorphized insulating ceramics can produce localized recrystallization on a nanometer scale. Similar electron irradiation techniques were used to nucleate monodispersed compound semiconductor nanocrystals formed by ion implantation of the elemental components into fused silica. Methods for the formation of novel structural relationships between embedded nanocrystals and their hosts have been developed and the results presented here demonstrate the general flexibility of ion implantation and irradiation techniques for producing unique near-surface microstructures in ion-implanted host materials.

XAS and XMCD studies of magnetic properties modifications of Pt/Co/Au and Pt/Co/Pt trilayers induced by Ga+ions irradiation

2015 ◽  
Vol 22 (3) ◽  
pp. 753-759 ◽  
Author(s):  
Piotr Mazalski ◽  
Iosif Sveklo ◽  
Zbigniew Kurant ◽  
Katharina Ollefs ◽  
Andrei Rogalev ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Magnetic Circular Dichroism ◽  
Perpendicular Magnetic Anisotropy ◽  
Local Environment ◽  
Two Dimensional ◽  
High Fluence ◽  
X Ray ◽  
Plane Anisotropy ◽  
X Ray Absorption ◽  
Reference Samples

Magnetic and magneto-optical properties of Pt/Co/Au and Pt/Co/Pt trilayers subjected to 30 keV Ga+ion irradiation are compared. In two-dimensional maps of these properties as a function of cobalt thickness and ion fluence, two branches with perpendicular magnetic anisotropy (PMA) for Pt/Co/Pt trilayers are well distinguished. The replacement of the Pt capping layer with Au results in the two branches still being visible but the in-plane anisotropy for the low-fluence branch is suppressed whereas the high-fluence branch displays PMA. The X-ray absorption spectra and X-ray magnetic circular dichroism (XMCD) spectra are discussed and compared with non-irradiated reference samples. The changes of their shapes and peak amplitude, particularly for the high-fluence branch, are related to the modifications of the local environment of Co(Pt) atoms and the etching effects induced by ion irradiation. Additionally, in irradiated trilayers the XMCD measurements at the PtL2,3-edge reveal an increase of the magnetic moment induced in Pt atoms.

Package design and development of a low cost high temperature (250°C), high current (50+A), low inductance discrete power package for advanced Silicon Carbide (SiC) and Gallium Nitride (GaN) devices

2013 ◽  
Vol 2013 (1) ◽  
pp. 000592-000597
Author(s):  
B. McPherson ◽  
B. Passmore ◽  
P. Killeen ◽  
D. Martin ◽  
A. Barkley ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gallium Nitride ◽  
High Temperature ◽  
Power Density ◽  
High Performance ◽  
Elevated Temperatures ◽  
Power Converter ◽  
System Level ◽  
High Current ◽  
Package Design

The demands for high-performance power electronics systems are rapidly surpassing the power density, efficiency, and reliability limitations defined by the intrinsic properties of silicon-based semiconductors. The advantages of post silicon materials, including Silicon Carbide (SiC) and Gallium Nitride (GaN), are numerous, including: high temperature operation, high voltage blocking capability, extremely fast switching, and superior energy efficiency. These advantages, however, are severely limited by conventional power packages, particularly at temperatures higher than 175°C and >100 kHz switching speeds. In this discussion, APEI, Inc. presents the design of a newly developed discrete package specifically intended for high performance, high current (>50A), rapid switching, and extended temperature (>250°C) wide band gap devices which are now readily available on the commercial market at voltages exceeding 1200V. Finite element analysis (FEA) results will be presented to illustrate the modeling process, design tradeoffs, and critical decisions fundamental to a high performance package design. A low profile design focuses on reducing parasitic impedances which hinder high speed switching. A notable increase in the switching speed and frequency reduces the size and volume of associated filtering components in a power converter. Operating at elevated temperatures reduces the requirements of the heat removal system, ultimately allowing for a substantial increase in the power density. Highlights of these packages include the flexibility to house a variety of device sizes and types, co-packaged antiparallel diodes, a terminal layout designed to allow rapid system configuration (for paralleling or creating half- and full-bridge topologies), and a novel wire bondless backside cooled construction for lateral GaN HEMT devices. Specific focus was placed on minimizing the cost of the materials and fabrication processes of the package components. The design of the package is discussed in detail. High temperature testing of a SiC assembly and electrical test results of a high frequency GaN based boost converter will be presented to demonstrate system level performance advantages.

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