scholarly journals Analysis of Experiments in Helium Microbeam Mixing

1991 ◽  
Vol 235 ◽  
Author(s):  
John B. Davis ◽  
R. E. Benenson ◽  
David Peak
Keyword(s):  
Dose Rate ◽  
Ion Beam ◽  
Liquid Nitrogen Temperature ◽  
Enhanced Diffusion ◽  
Interface Width ◽  
Interface Growth ◽  
Radiation Enhanced Diffusion ◽  
Order Of Magnitude ◽  
Constant Dose ◽  
Diffusion Of Vacancies

ABSTRACTWe have continued to investigate ion-beam mixing in bilay-er targets irradiated by 2-MeV He+ microbeams at room temperature. Although we have previously reported a linear dependence of interface width on dose for Cu/Al targets 1, more extensive results have not supported this conclusion, within statistical uncertainty, it appears that the interface width in Cu/Al (1) is proportional to the square root of dose, at constant dose rate, (2) is larger in Al than in Cu, for the same dose, (3) is proportional to the 1/4 power of dose rate, and (4) is absent at liquid nitrogen temperature. Calculations of the expected interface growth rate from a radiation-enhanced diffusion model have provided order-of-magnitude agreement with observed rates. Additionally, intermixing of Cu and Al outside the damaged area may indicate significant transverse diffusion of vacancies.

Diffusion of Au in Amorphous Si During Ion-Beam Irradiation

1988 ◽  
Vol 100 ◽  
Author(s):  
F. Priolo ◽  
J. M. Poate ◽  
D. C. Jacobson ◽  
J. Linnros ◽  
J. L. Batstone ◽  
...  
Keyword(s):  
Activation Energy ◽  
Ion Beam ◽  
Liquid Nitrogen Temperature ◽  
Ion Beam Irradiation ◽  
Arrhenius Behavior ◽  
Enhanced Diffusion ◽  
Dose Rates ◽  
Radiation Enhanced Diffusion ◽  
Amorphous Si ◽  
Temperature Radiation

ABSTRACTWe have measured the radiation-enhanced diffusion of Au in amorphous Si in the temperature range 77–700 K. Gold was implanted to depths of 500Å at concentrations of an atomic %. The samples were than amorphized to depths of -2μm using MeV Ar implants at liquid nitrogen temperature. Radiation-enhanced diffusion was induced by a 2.5 MeV Ar beam at doses of 2×1016−2×1017/cm2 and dose rates of 7×1012−7×1013/cm2sec. The diffusion coefficients show three well defined regions. At temperatures <400K diffusion is essentially athermal and due to ballistic mixing. At temperatures between 400K and 700K the diffusion, which is considerably enhanced over the usual thermal values, has an Arrhenius behavior with an activation energy of 0.37 eV. At higher temperatures thermal diffusion, with an activation energy of 1.42 eV, dominates.

A Comparison of Atomic Mixing Behaviour of Cu- Au and Cu- W Systems for Room Temperature and Low Temperature Irradiation

1981 ◽  
Vol 7 ◽  
Author(s):  
Z.L. Wang ◽  
J.F.M. Westendorp ◽  
S. Doorn ◽  
F.W. Saris
Keyword(s):  
Ion Beam ◽  
Pronounced Difference ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Atomic Displacements ◽  
Radiation Enhanced Diffusion ◽  
Thermodynamic Conditions ◽  
Order Of Magnitude ◽  
Atomic Mixing ◽  
Mixing Behaviour

ABSTRACT300 keV Kr ion irradiations with doses varying from 2× 1015 to 2× 1016 at/cm2 have been applied to initiate mixing of Cu-Au and Cu-W systems. As under normal thermodynamic conditions the Cu-Au system is miscible whereas the Cu-W system is not, the comparison of both systems provides a test for the current theories on ion-beam mixing. A pronounced difference in mixing phenomena is observed for both systems; in the Cu-Au system atomic displacements are one order of magnitude larger than those in the Cu-W system. In addition, a drastic temperature dependence of ion-beam mixing in the Cu-Au system has been found. The mixing is suppressed by lowering the substrate temperature during irradiation. These results show that radiation enhanced diffusion is the mechanism underlying the ion-beam mixing of Cu and Au. Results for the Cu-W system are consistent with a collisional mixing model.

Ion beam mixing and radiation-enhanced diffusion in metallic glasses

1988 ◽  
Vol 140 ◽  
pp. 267-275 ◽  
Author(s):  
R.S. Averback ◽  
H. Hahn ◽  
Fu-Rong Ding
Keyword(s):  
Metallic Glasses ◽  
Ion Beam ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion

Atomic Transport in Irradiated Solids

1993 ◽  
Vol 311 ◽  
Author(s):  
R.R. Averback ◽  
Mai Ghaly ◽  
Y.Y. Lee ◽  
H. Zhu
Keyword(s):  
Ion Beam ◽  
Rapid Quenching ◽  
Primary Role ◽  
Melting Points ◽  
Crystalline Materials ◽  
Enhanced Diffusion ◽  
Atomic Transport ◽  
Radiation Enhanced Diffusion ◽  
Radiation Induced ◽  
Kinetics Of

ABSTRACTAtomic transport in irradiated solids has been investigated in both the prompt and delayed regimes. Prompt effects are revealed on an atomic level through molecular dynamics computer simulations. It is demonstrated that for metals like gold, which have high atomic numbers and low melting points, thermal spikes play a primary role in the cascade dynamics and that concepts like melting and rapid quenching are useful descriptions. Surface effects in these metals are also discussed. For metals with higher melting points and lower atomic numbers, the cascade dynamics are determined almost exclusively by energetic collisions far above thermal energies. This is illustrated by simulations of cascades in NiAl. The effect of the high ordering energy in this intermetallic compound on the radiation-induced defect structure has also been studied.Atomic transport in the delayed regime is illustrated by two examples: an order-disorder alloy, Cu3Au, and an amorphous alloy, NiZr. The first example is used to illustrate various aspects of radiation enhanced diffusion (RED): ion beam mixing, diffusion kinetics, the effects of primary recoil spectrum, and the importance of chemical order. The second example illustrates that the basic theory of RED, which was developed to describe crystalline materials, appears to work adequately for amorphous metal alloys, suggesting that similar mechanisms may be operating. It is shown, however, that the kinetics of RED observed in amorphous alloys are not unique to point defect models.

Ar+ Induced Interfacial Mixinc in the Pd/Cu Bilayer System

1989 ◽  
Vol 157 ◽  
Author(s):  
H.K. Kim ◽  
J.H. Song ◽  
S.K. Kim ◽  
K. Jeong ◽  
C.N. Whang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ion Beam ◽  
Layer By Layer ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Bilayer System ◽  
Radiation Enhanced Diffusion

ABSTRACTIon beam mixing of a Pd/Cu bilayer is studied using irradiation with 80 keV Ar+ ions at room temperature. RBS analysis shows that intermixing has occurred across the Pd/Cu interface, and that the mixing amount increases with increasing ion dose, which agrees well with a model for radiation enhanced diffusion. It is found that the Cu3Pd phase grows in a layer-by-layer manner.

Diffusion Induced Grain Boundary Migration in Ion-Beam Mixed Fe-AL

1982 ◽  
Vol 40 ◽  
pp. 634-635 ◽  
Author(s):  
Shankara K. Prasad ◽  
Herbert Herman ◽  
Alexander H. King ◽  
Allen Goland
Keyword(s):  
Thin Film ◽  
Thin Layer ◽  
Boundary Migration ◽  
Ion Beam ◽  
Bulk Diffusion ◽  
Grain Boundary Migration ◽  
Recoil Implantation ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Mixed Layers

Ion beam intermixing is a newly investigated process wherein an ion beam is used to induce a reaction between a deposited thin layer and the substrate. The ion beam induced intermixing and microalloying at the interface can be due to three processes: 1. Recoil implantation 2. Cascade mixing 3. Radiation enhanced diffusion. Mixing due to recoil implantation has been studied by Nelson and was shown to result in very shallow mixed layers. However, in their recent investigation of Pt-Si, Pd-Si and Al-Ge and other systems, Tsaur et.al, have observed the formation of a thick surface alloy which is metastable in nature. They attribute this intermixing of the deposited thin film and the substrate, and the eventual "epitaxial" growth, to cascade overlap and radiation enhanced bulk diffusion. The present work provides evidence for the role played by grain boundaries in both intermixing and grain growth.

Ion Beam Etching of Silicon: Implantation and Diffusion of Noble Gas Atoms, and Gettering of Copper

1989 ◽  
Vol 163 ◽  
Author(s):  
William D. Sawyer ◽  
Jörg Schmälzlin ◽  
Jörg Weber
Keyword(s):  
Surface Layer ◽  
Noble Gas ◽  
Ion Beam ◽  
Diffusion Annealing ◽  
Ion Beam Etching ◽  
Enhanced Diffusion ◽  
Radiation Enhanced Diffusion ◽  
Silicon Implantation ◽  
And Diffusion ◽  
Low Temperature Photoluminescence

AbstractDefects introduced into silicon by ion beam etching are investigated by low-temperature photoluminescence (PL) and Rutherford backseattering (RBS) measurements. The RBS results show that during the ion beam etch a highly damaged surface layer is formed which contains a large concentration of Ar atoms. The Ar atoms then diffuse out of the surface and into the crystalline bulk by some form of radiation enhanced diffusion. Annealing of the etched samples at 350°C results in the formation of noble gas defects known from previous PL studies of ion implanted silicon. When the samples are annealed at 650βC PL lines due to new defects are formed. Although little is known about their structure, we show that the new Ar defects getter small copper contaminations very effectively.

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