Use of C<sub>60</sub> cluster projectiles for sputter depth profiling of polycrystalline metals

Sun, Shilong; Szakal, Christopher; Roll, T.; Mazarov, Paul; Wucher, A.; Winograd, Nicholas

doi:10.1002/sia.1923

Cited by 56 publications

(48 citation statements)

References 20 publications

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“…In comparison to experiments with metal samples, Sun et al previously determined the interface width between the two constituents of the Ni:Cr sample to be approximately 8.7 nm in thickness for an incident energy of 20 keV. 11 This value is consistent with the result from this simulation giving that about 8-9 nm of topography has been created in removing only 0.24 nm of material as shown in Figures 2 and 3. Thus crater depths calculated for single impacts on flat surfaces are not appropriate for experimental interface widths.…”

Section: Resultssupporting

confidence: 81%

“…1,2 Their abilities of nonlinear enhancement of yield, reduced chemical damage, and reduced damage depth have opened the door to a wide array of depth profiling capabilities. [3][4][5][6][7][8][9][10][11][12] For example, it is possible to analyze multilayered structures used in the electronics/semiconductor industry, 6,13 as well as perform molecular specific depth profiles of cells and other biologically important systems. [13][14][15][16][17][18][19][20] The critical issue for quantitative interpretation of depth profiles is the interface width, a quantity that reflects how precisely one can measure a change in composition.…”

Section: Introductionmentioning

confidence: 99%

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A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

2009

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ࠗ w This paper contains enhanced objects available on the Internet at http://pubs.acs.org/JPCC.Using 20-keV C 60 on a Ag sample, multiple cluster bombardment events have been performed with molecular dynamics simulations. The purpose of this investigation is to develop a protocol for making depth profiling simulations tractable, as well as to examine the topographical effects which arise due to multiple impacts on smooth surfaces. The results show that when the total yield is equivalent to the removal of one atomic layer (0.24 nm), the distribution of the ejected particles is spread throughout the top 5.5 nm of the sample. Examples of individual bombardment events on the damaged surface exhibit a diversity of dynamics that is not observed on flat surfaces. Using the computational methods outlined, we have been able to run depth profiling simulations on a large-scale system.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

2009

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“…For example, these sources can be focused onto the sample with a probe size about 1 micron, allowing greatly improved molecule-specific imaging experiments. The high secondary ion yield associated with the cluster/solid interaction also allows for molecular depth profiling studies without the accompanying damage accumulation normally associated with atomic bombardment [7][8][9][10][11][12][13][14][15][16][17].…”

mentioning

confidence: 99%

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

Sun

Szakal

Winograd

et al. 2005

J. Am. Soc. Mass Spectrom.

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The ion bombardment-induced release of particles from a metal surface is investigated using energetic fullerene cluster ions as projectiles. The total sputter yield as well as partial yields of neutral and charged monomers and clusters leaving the surface are measured and compared with corresponding data obtained with atomic projectile ions of similar impact kinetic energy. It is found that all yields are enhanced by about one order of magnitude under bombardment with the C 60 ϩ cluster projectiles compared with Ga ϩ ions. In contrast, the electronic excitation processes determining the secondary ion formation probability are unaffected. The kinetic energy spectra of sputtered particles exhibit characteristic differences which reflect the largely different nature of the sputtering process for both types of projectiles. In particular, it is found that under C 60 ϩ impact (1) the energy spectrum of sputtered atoms peaks at significantly lower kinetic energies than for Ga ϩ bombardment and (2) the velocity spectra of monomers and dimers are virtually identical, a finding which is in pronounced contrast to all published data obtained for atomic projectiles. T he elucidation of the mechanism of interaction of energetic polyatomic or cluster ions with surfaces is of current interest since these projectiles are now being extensively employed as desorption probes in secondary ion mass spectrometry (SIMS) experiments [1,2]. Because of their propensity to produce higher molecular ion signals than corresponding atomic ions and the emergence of commercially available C 60 ϩ [3,4] and Au 3 ϩ [5, 6] ion guns, applications have expanded dramatically. For example, these sources can be focused onto the sample with a probe size about 1 micron, allowing greatly improved molecule-specific imaging experiments. The high secondary ion yield associated with the cluster/solid interaction also allows for molecular depth profiling studies without the accompanying damage accumulation normally associated with atomic bombardment [7][8][9][10][11][12][13][14][15][16][17].The mechanisms associated with the observed secondary ion yield enhancement are not yet clear, although details are emerging quickly. A basic question that must be resolved is to determine whether the yield enhancement occurs as a consequence of increased ionization efficiency, or is due to more effective sputtering in the neutral desorption channel. There is mixed information about this point. For In and Ag surfaces, for example, it has been shown that the enhanced secondary ion yield under SF m ϩ bombardment (m ϭ 1-5) largely arises from the enhanced ionization efficiency attributable to implanted F atoms [18]. For organic systems, however, very high removal rates of neutral species have been reported [2], obviating the need to invoke enhancement of the secondary ionization probability. Most recently, yields and velocity distributions were measured for In and In 2 sputtered from In surfaces bombarded with Au ϩ , Au 2 ϩ , and Au 3 ϩ [19]. Although these experiments do not ad...

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“…So, it was necessary to decrease the crater size and to increase the bombarding energy in order to hold duration of the analysis in the acceptable limits. Beam-induced interlayer mixing contributes to the degradation of SIMS profiles as well; it can be considerably suppressed only by lowering the bombarding energy down to 100-200 eV [37] or by using polyatomic or cluster projectiles [38][39][40]. At present, such techni- ques are beyond the capabilities of the SIMS instrument used in this study.…”

Section: Resultsmentioning

confidence: 95%

High-temperature oxidation of CrN/AlN multilayer coatings

Bardi

Chenakin²,

Ghezzi

et al. 2005

Applied Surface Science

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Experiments are reported on sputter depth profiling of CrN/AlN multilayer abrasive coatings by secondary ion mass spectrometry (SIMS) coupled with sample current measurements (SCM). The coatings were deposited by a closed-field unbalanced magnetron sputtering. It is shown that after oxidation tests, performed in air at 900 8C for 2 h and at 1100 8C for 4 h, the layered structure begins to degrade but is not destroyed completely. Oxidation at 1100 8C for 20 h causes total destruction of the coatings that can be attributed to a fast diffusion of oxygen, nickel, manganese and other elements along defect paths (grain boundaries, dislocations, etc.) in the coating. There are practically no nitrides in the near-surface layer after such a treatment and all the metallic components are in the oxidized form as follows from the data obtained by X-ray photoelectron spectroscopy (XPS). According to XPS and mass-resolved ion scattering spectrometry (MARISS), the surface content of Al in the heat-treated coatings has decreased in comparison with the as-received sample and that of Cr increased. Both XPS and MARISS data exhibit real increase in superficial concentration of the substrate materials (Mn and Ni) that is controversial if using SIMS alone. SCM turned out to be an informative depth profiling method complementary to more expensive and complicated SIMS, being particularly useful for structures with different secondary electron emission properties of the layers. SCM with predetermined SIMS calibration allows a routine characterization of coatings and other multilayer structures, particularly, in situations where the expenses of analysis can be justified.www.elsevier.com/locate/apsusc

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Use of C₆₀ cluster projectiles for sputter depth profiling of polycrystalline metals

Cited by 56 publications

References 20 publications

A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles

High-temperature oxidation of CrN/AlN multilayer coatings

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Use of C60 cluster projectiles for sputter depth profiling of polycrystalline metals

Cited by 56 publications

References 20 publications

A Computational Investigation of C60 Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

A Computational Investigation of C60 Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

Energetic ion bombardment of Ag surfaces by C60+ and Ga+ projectiles

High-temperature oxidation of CrN/AlN multilayer coatings

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Use of C₆₀ cluster projectiles for sputter depth profiling of polycrystalline metals

A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

A Computational Investigation of C₆₀ Depth Profiling of Ag: Molecular Dynamics of Multiple Impact Events

Energetic ion bombardment of Ag surfaces by C₆₀⁺ and Ga⁺ projectiles