Measurements of point defect creation related to high densities of electronic excitations produced by energetic carbon cluster bombardments

doi:10.1016/0168-583X(94)96075-5

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Volume 88, Issues 1–2, 3 April 1994, Pages 25-28

https://doi.org/10.1016/0168-583X(94)96075-5 Get rights and content

Abstract

LiF single crystals have been bombarded at room temperature with C₃ and C₅ clusters with energies of 1.74 MeV/carbon atom and fluences ranging from 10¹² to 1014 carbon atoms/cm². Point defects (color centers: F, F₂,…) resulting from electronic excitation processes were measured by optical absorption spectroscopy. The defect concentrations were compared to those produced by irradiations with single ¹²C ions with the same respective energy and dose. Using a differential optical absorption technique, it was possible to determine the defect concentrations close to the sample surface, when the tracks associated to each carbon atom of the cluster overlap. In this zone, where the “cluster effect” is maximum due to the very high density of electronic excitations, enhanced defect production is observed. Defect concentrations as large as those obtained previously by Kr and Xe irradiations at GANIL have been measured. In addition to the high defect production rates observed, aggregation laws (i.e. F → F₂) characteristic of cluster irradiations are also deduced.

References (12)

A. Perez et al.
Nucl. Instr. and Meth.
(1976)
J.P. Biersack
P. Sigmund
Appl. Phys. Lett.
(1974)
T.Diaz de la Rubia et al.
J. Mater. Res.
(1989)
J. Fain et al.
Radiat. Res.
(1974)

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Citation Excerpt :
Such an interaction produces localized lattice damages which one can not see with a monomer ion with comparable energy. With increase in cluster size there can be a nonlinear lattice damage buildup which has been studied at both keV and MeV energies with various ion target combinations. [4–11] One of the earlier works using cluster ions was by Perez et al. [4] where C3 and C5 clusters at 1.74 MeV/atom were used to create point defects in LiF.
Si(1 0 0) substrates were implanted with $C_{n}^{-}$ (n = 1, 3, 5) ions at 5 keV/atom for fluence ranging between 1 × 10¹⁴ and 1.6 × 10¹⁵ atoms cm⁻². The implanted samples were analysed using channeling Rutherford backscattering spectrometry with growth in the surface peak intensity representing growth in damage. At lower fluence cluster ion implantation has been found to result in nonlinear damage production, the nonlinearity increasing with cluster size. Increase in fluence has been found to result in lower nonlinearity. The present values of nonlinearity are much higher for those obtained with C clusters in Si at MeV energies which is primarily because of beam induced annealing effects, coming from electronic energy loss. The cross section for damage production has also been estimated which for all the three values of n yield a consistent result.
Non-linear effect of cluster irradiation on chemical modification of polycarbonate
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Chemical modification of single-ion and cluster-ion irradiated polymer films was studied using attenuated total reflectance Fourier transform infrared spectroscopy. Various single ions (B⁺, C⁺, Si⁺ and Cu⁺ ions at energies between 0.19 and 2.255 MeV) and cluster ions (0.19 MeV/atom-C⁺₄,C⁺₆ and C⁺₈, 0.3 MeV/atom-C⁺₄ and C⁺₆) were irradiated on polycarbonate, and the effect of single-ion irradiation on the peak intensities for OH, CH₂ and CH₃ bands was compared with that of cluster-ion irradiation. In the cluster-ion irradiation, the accumulated energy density around ion track becomes higher by simultaneous impacts of several ions to small area. CH₂ bond formation was anomalously enhanced in the samples irradiated with 0.19 MeV/atom-C⁺₈ and 0.3 MeV/atom-C⁺₆. High energy density of 0.19 MeV/atom-C⁺₈ and 0.3 MeV/atom-C⁺₆ irradiation was found to be responsible for the anomalous enhancement.
Damage production in silicon by MeV Si cluster irradiation
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We have accelerated clusters of C_n⁺ (n = 2–8), Al_n⁺ (n = 2–4), Si_n⁺ (n = 2–4) and Ge_n⁺ (n = 2, 3) to MeV energies at the 1.7 MV tandem accelerator of Peking University. The defect concentrations produced by cluster irradiation were measured by channelling Rutherford backscattering (CRBS). We took notice of the fact that the defect concentration depends significantly on the dose rate at the same energy and dose. In order to compare the defect density produced by Si_n⁺ irradiation, irradiation at the same dose rate for different cluster sizes was preferred. The non-linear effect of defect concentration produced by Si_n⁺ irradiation in the near surface region has been measured. Defect self-annealing for Si₂ and enhanced defect production for Si₃ are observed. This behaviour is well described by Tombrello's model for defect production by heavy ions in metals.
MeV cluster ions from the Erlangen tandem accelerator
1996, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
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Investigation of damage formation by gas cluster ion bombardment
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Ar cluster ion bombardment has been carried out to study impact processes of cluster ions on solid surfaces with various ion energies. In the case of Ar cluster ion bombardment with an energy of 150 keV, a damaged layer of about 200 Å thickness was formed. This thickness is significantly larger than the value calculated for Ar monomer ions with the same velocity as the cluster ions. The thickness of the damaged layer is strongly dependent on the cluster size. Surprisingly, thicker damaged layers are formed with increasing cluster size, if the cluster ion energies are same. These results strongly suggest a new damage formation mechanism by high-energy cluster ion bombardment.
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1996, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Latent ion tracks in polymers can incorporate dyes at high concentrations. This is of interest in a number of applications. Dyes may also be used as sensitive probes to study the fine structure of latent ion tracks. In this work, we discuss the dependence of dye uptake on both time and mean transferred electronic energy density, and also consider the depth distribution of dyes along ion tracks. Special attention is paid to dye uptake in tracks created by energetic carbon cluster ions.

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Measurements of point defect creation related to high densities of electronic excitations produced by energetic carbon cluster bombardments

Abstract

Nucl. Instr. and Meth.

Appl. Phys. Lett.

J. Mater. Res.

Radiat. Res.