Implantation of Nitrogen into Ti/Al, Ni/Ti, and Ni/Al Bilayers

1991 ◽  
Vol 235 ◽  
Author(s):  
D. O. Boerma ◽  
T. Corts
Keyword(s):  
Nuclear Reaction Analysis ◽  
Si Substrate ◽  
Major Fraction ◽  
High Chemical ◽  
Gaussian Shape ◽  
Depth Profiles ◽  
Implantation Temperature ◽  
Projected Range ◽  
A Minor ◽  
Metal Layers

ABSTRACTTi/Al, Ni/Ti, and Ni/Al bilayers were produced by evaporation on a Si substrate. The thicknesses of the composing layers were in the 50–200 nm range. The as-evaporated bilayers were implanted with doses of 0.4–2.5 · 1017 of 15N ions/cm2. The 15N energy was chosen so that the calculated projected range was either in the middle of the top Ni layer, or coincided with the interface between the metal layers. The implantation temperature was varied in the range from 25 °C to 245 °C. The 15N depth profiles as measured with nuclear reaction analysis (NRA) were found to have the expected Gaussian shape for the Ti/Al bilayers. However, in the Ni/Ti and Ni/Al layers very asymmetric 15N profiles were observed, with a major fraction of N atoms in the Ti or Al layer, and a minor fraction in the Ni layer. The N concentrations in the Al or Ti layers were found to be almost constant. A massive redistribution of N atoms must have taken place in all three metals during the implantations, to form the observed profiles. We speculate that this remarkable phenomenon, which occurs even below 80°C, can be explained by interstitial diffusion of N atoms and subsequent trapping in Ti or Al, which have a high chemical affinity for nitrogen. The N atoms remaining in the Ni layer after implantation were found to migrate out of this layer during annealing at temperatures ≥250°C.

Parameters for Nitrogen Diffusion in Ni, Ti, and Al Obtained from Implanted Bilayers

1992 ◽  
Vol 279 ◽  
Author(s):  
K. K. Bourdelle ◽  
D. O. Boerma
Keyword(s):  
Nuclear Reaction ◽  
Room Temperature ◽  
Vacuum Annealing ◽  
Nitride Layer ◽  
Nuclear Reaction Analysis ◽  
Nitrogen Diffusion ◽  
Depth Profiles ◽  
Solid Interface ◽  
Before And After ◽  
Concentration Depth Profiles

ABSTRACTNi foils and samples consisting of bilayers of Ni or Fe on Al, Ti or Si were implanted at room temperature with 15N+ ions to fluences of around 1×l017 N/cm2. The concentration depth profiles of 15N were determined with nuclear reaction analysis before and after vacuum annealing. It was found that the penetrability for N atoms of the surface and the solid/solid interface plays an important role in the N redistribution during implantation or annealing. The formation of a nitride layer or nitride clusters in Ni and Fe was deduced. Parameters for N migration determined for the metals under investigation are discussed in terms of models.

scholarly journals Phosphotyrosine phosphatase associated with band 3 protein in the human erythrocyte membrane

1996 ◽  
Vol 314 (3) ◽  
pp. 881-887 ◽  
Author(s):  
Yehudit ZIPSER ◽  
Nechama S. KOSOWER
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Intact Cell ◽  
Band 3 ◽  
Band 3 Protein ◽  
Human Erythrocyte Membrane ◽  
Major Fraction ◽  
Phosphotyrosine Phosphatase ◽  
A Minor ◽  
Triton X

The anion-exchange band 3 protein is the main erythrocyte protein that is phosphorylated by tyrosine kinase. To study the regulation of band 3 phosphorylation, we examined phosphotyrosine phosphatase (PTP) activity in the human erythrocyte. We show that the human erythrocyte membrane contains a band 3-associated neutral PTP which is activated by Mg2+ and inhibited by Mn2+ and vanadate. The PTP is active in the intact cell and in the isolated membrane. A major fraction of the PTP is tightly bound to the membrane and can be extracted from it by Triton X-100; a minor part is associated with the Triton X-100-insoluble cytoskeleton. The behaviour of the PTP parallels that of band 3, the major fraction of which is extractable by detergents with a minor fraction being anchored to the cytoskeleton. Moreover, band 3 is co-precipitated when the PTP is immunoprecipitated from solubilized membranes, and PTP is co-precipitated when band 3 is immunoprecipitated. The PTP appears to be related to PTP1B (identified using an antibody to an epitope in its catalytic domain and by molecular mass). The system described here has a unique advantage for PTP research, since it allows the study of the interaction of a PTP with an endogenous physiological substrate that is present in substantial amounts in the cell membrane. The membrane-bound, band 3-associated, PTP may play a role in band 3 function in the erythrocyte and in other cells which have proteins analogous to band 3.

Annealing of Pb-Implanted SrTiO3 in The Presence of Water Vapour: A Study Using D218O Labelling

1991 ◽  
Vol 235 ◽  
Author(s):  
J. C. McCallum ◽  
T. W. Simpson ◽  
I. V. Mitchell ◽  
J. Rankin ◽  
L. A. Boatner
Keyword(s):  
Water Vapour ◽  
Rate Increase ◽  
Secondary Ion Mass Spectrometry ◽  
Solid Phase ◽  
Nuclear Reaction Analysis ◽  
Doubly Labelled Water ◽  
Time Resolved ◽  
Depth Profiles ◽  
Conventional Furnace ◽  
Secondary Ion

ABSTRACTWe report new measurements of the regrowth behaviour of Pb-implanted SrTiO3 crystals in the presence of water vapour. Doubly labelled water vapour, D218O, at greater than 95% enrichment in each isotope has been added to the annealing ambient and depth profiles of D and 18O have been obtained from the regrown crystals using secondary ion mass spectrometry (SIMS). The D and 18O content has also been measured by nuclear reaction analysis (NRA) using the reactions D(3He,p)4 He and 18O(p,α)15 N. The crystals were regrown in a conventional furnace under a controlled gas ambient and time-resolved optical reflectivity (TRR) was used to dynamically monitor the regrowth rate during the anneal. An enhancement of the solid-phase epitaxial regrowth rate is observed when water vapour is added to the annealing ambient. This rate increase is accompanied by incorporation of D throughout the regrown layer. 18O is incorporated into the lattice but does not appear to penetrate deep enough to influence the regrowth rate.

scholarly journals Hexose metabolism in pancreatic islets. Inhibition of hexokinase

1984 ◽  
Vol 223 (2) ◽  
pp. 447-453 ◽  
Author(s):  
M H Giroix ◽  
A Sener ◽  
D G Pipeleers ◽  
W J Malaisse
Keyword(s):  
Major Fraction ◽  
Intracellular Space ◽  
Extracellular Glucose ◽  
Low Glucose ◽  
Glucose Phosphorylation ◽  
Metabolic Data ◽  
A Minor ◽  
Glycolytic Rate ◽  
State Content ◽  
Hexose Metabolism

In islet homogenates, hexokinase-like activity (Km 0.05 mM; Vmax. 1.5 pmol/min per islet) accounts for the major fraction of glucose phosphorylation. Yet the rate of glycolysis in intact islets incubated at low glucose concentrations (e.g. 1.7 mM) sufficient to saturate hexokinase only represents a minor fraction of the glycolytic rate observed at higher glucose concentrations. This apparent discrepancy between enzymic and metabolic data may be attributable, in part at least, to inhibition of hexokinase in intact islets. Hexokinase, which is present in both islet and purified B-cell homogenates, is indeed inhibited by glucose 6-phosphate (Ki 0.13 mM) and glucose 1,6-bisphosphate (Ki approx. 0.2 mM), but not by fructose 2,6-bisphosphate. In intact islets, the steady-state content of glucose 6-phosphate (0.26-0.79 pmol/islet) and glucose 1,6-bisphosphate (5-48 fmol/islet) increases, in a biphasic manner, at increasing concentrations of extracellular glucose (up to 27.8 mM). From these measurements and the intracellular space of the islets, it was estimated that the rate of glucose phosphorylation as catalysed by hexokinase represents, in intact islets, no more than 12-24% of its value in islet homogenates.

Intermetallic formation with indium solder

1988 ◽  
Vol 46 ◽  
pp. 564-565
Author(s):  
Robert Darveaux ◽  
Iwona Turlik ◽  
John Hren
Keyword(s):  
Thin Film ◽  
Film Structure ◽  
Si Substrate ◽  
Hot Plate ◽  
Intermetallic Formation ◽  
X Ray ◽  
Power Cycling ◽  
Solder Bulk ◽  
As Stress ◽  
Metal Layers

This study investigates metallurgical interactions between indium solder and thin film metal layers. Intermetallic formation is an important reliability concern with solder joints because the compounds are typically brittle phases that act as stress concentrators during thermal and power cycling of a device [1], Experiments were carried out for the thin film structure shown schematically in Figure 1. For convenience, 80 nm of Cr and 1.0 μm of Cu were e-beam evaporated on a Si substrate, followed by electroless plating ∼1μm Niklad 752 nickel (1%B). The substrate was diced, then tinned on a hot plate @ 180+/- 5*C using Blackstone #1452 flux. The solder was molten for times of 30,60,120, and 240 sec. Indium was etched away in concentrated HC1 to reveal the intermetallic formation. Shown in Figure 2 is a rod-like eutectic found in the solder bulk. Debye-Scherrer x-ray powder diffraction and energy dispersive x-ray spectrometry were used to identify the phases as In/ϕ-InCu.

The synergies between displacement damage creation and hydrogen presence: the effect of D ion energy and flux

2022 ◽  
Author(s):  
Sabina Markelj ◽  
Matic Pečovnik ◽  
Thomas Schwarz-Selinger ◽  
Mitja Kelemen
Keyword(s):  
Nuclear Reaction ◽  
Thermal Desorption ◽  
Rate Equation ◽  
Irradiation Time ◽  
Thermal Desorption Spectroscopy ◽  
Nuclear Reaction Analysis ◽  
Displacement Damage ◽  
Ion Energy ◽  
Depth Profiles ◽  
Different Temperatures

Abstract In this work the synergism between displacement damage creation and presence of hydrogen isotopes was studied. Tungsten samples were irradiated by 10.8 MeV W ions with or without the presence of D ions with two different energies of 300 eV/D and 1000 eV/D and different temperatures. In order to compare the results obtained with different exposure parameters the samples were afterwards additionally exposed to D ions at 450 K to populate the created defects. By increasing the W irradiation time, ion flux and energy, the increase of D concentration and D retention was observed as measured by nuclear reaction analysis and thermal desorption spectroscopy. By fitting the D depth profiles and D desorption spectra by the rate equation code MHIMS-R we could see that additional fill-levels were populated with higher flux and ion energy which ends up in higher final D concentration and retention as compared to experiments with lower D flux and energy.

Conductive Tungsten-Based Layers Synthesized by Ion Implantation into 6H-Silicon Carbide

1996 ◽  
Vol 438 ◽  
Author(s):  
H. Weishart ◽  
J. Schoneich ◽  
M. Voelskow ◽  
W. Skorupa
Keyword(s):  
Silicon Carbide ◽  
Room Temperature ◽  
Depth Distribution ◽  
Ostwald Ripening ◽  
Rutherford Backscattering Spectrometry ◽  
High Dose ◽  
Electrically Conductive ◽  
Gaussian Shape ◽  
Implantation Temperature ◽  
High Dose Implantation

AbstractWe studied high dose implantation of tungsten into 6H-silicon carbide in order to synthesize an electrically conductive layer. Implantation was performed at 200 keV with a dose of 1.2x 1017 WIcm 2 at temperatures between 200°C and 400°C. The influence of implantation temperature on the distribution of W in SiC was investigated and compared to results obtained earlier from room temperature (RT) and 500°C implants. Rutherford backscattering spectrometry (RBS) was employed to study the structure and composition of the implanted layers. Implantation at temperatures between RT and 300°C did not influence the depth distribution of C, Si and W. The W depth profile shows a conventional Gaussian shape. Implanting at higher temperatures led to a more confined W rich layer in the SiC. This confinement is explained by Ostwald ripening which is enabled during implantation at temperatures above 300°C. The depth of the implantation induced damage decreases slightly with increasing implantation temperature, except for 400°C implantation. The amount of damage, however, is significantly reduced only for implantation at 500°C.

Helium Migration Mechanisms in Polycrystalline Uranium Dioxide

2006 ◽  
Vol 985 ◽  
Author(s):  
Guillaume Martin ◽  
Pierre Desgardin ◽  
Philippe Garcia ◽  
Thierry Sauvage ◽  
Gaëlle Carlot ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Nuclear Reaction ◽  
Uranium Dioxide ◽  
Nuclear Reaction Analysis ◽  
Annealing Stage ◽  
Depth Profiles ◽  
Release Mechanisms ◽  
Helium Diffusion

AbstractThis study aims at identifying the release mechanisms of helium in uranium dioxide. Two sets of polycrystalline UO2 sintered samples presenting different microstructures were implanted with 3He ions at concentrations in the region of 0.1 at.%. Changes in helium concentrations were monitored using two Nuclear Reaction Analysis (NRA) techniques based on the 3He(d,α)1H reaction. 3He release is measured in-situ during sample annealing at temperatures ranging between 700°C and 1000°C. Accurate helium depth profiles are generated after each annealing stage. Results that provide data for further understanding helium release mechanisms are discussed. It is found that helium diffusion appears to be enhanced above 900°C in the vicinity of grain boundaries possibly as a result of the presence of defects.

XAFS Study of Fe K Edge in Al2O3-B2O3-Fe2O3-Na2O-SiO2 Glasses

2013 ◽  
Vol 1518 ◽  
pp. 59-64 ◽  
Author(s):  
S.V. Stefanovsky ◽  
A.A. Shiryaev ◽  
Y.V. Zubavichus ◽  
K.M. Fox ◽  
J.C. Marra
Keyword(s):  
Coordination Number ◽  
Valence State ◽  
Local Environment ◽  
Homogeneous Distribution ◽  
Major Fraction ◽  
Minor Fraction ◽  
State And Local ◽  
A Minor ◽  
Fe Ions

ABSTRACTValence state and local environment of Fe in complex glasses related to the system Al2O3-B2O3-Fe2O3-Na2O-SiO2 were studied. In all the glasses, the major fraction of Fe exists as Fe3+ ions but a minor fraction of Fe2+ ions especially in the glass with the lowest K=[SiO2]/[B2O3] ratio was also present. Average Fe—O distance in the first shell is 1.80-1.85 Å and coordination number is 4-6. The intensity due to the second sphere is rather weak demonstrating homogeneous distribution of Fe ions in the glass.

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