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John C. Vickerman - One of the best experts on this subject based on the ideXlab platform.
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tof sims with argon gas cluster Ion beams a comparison with c60
Analytical Chemistry, 2011Co-Authors: Sadia Rabbani, John S. Fletcher, Nicholas P. Lockyer, Andrew M Barber, John C. VickermanAbstract:Time-of-flight secondary Ion mass spectrometry (TOF-SIMS) is an established technique for the characterizatIon of solid sample surfaces. The introductIon of Polyatomic Ion beams, such as C60, has provided the associated ability to perform molecular depth-profiling and 3D molecular imaging. However, not all samples perform equally under C60 bombardment, and it is probably naive to think that there will be an Ion beam that will be applicable in all situatIons. It is therefore important to explore the potential of other candidates. A systematic study of the suitability of argon gas cluster Ion beams (Ar-GCIBs) of general compositIon Arn+, where n = 60–3000, as primary particles in TOF-SIMS analysis has been performed. We have assessed the potential of the Ar-GCIBs for molecular depth-profiling in terms of damage accumulatIon and sputter rate and also as analysis beams where spectral quality and secondary Ion yields are considered. We present results with direct comparison with C60 Ions on the same sample in ...
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InvestigatIon of molecular weight effects of polystyrene in ToF-SIMS using C60+ and Au+ primary Ion beams
Applied Surface Science, 2008Co-Authors: Alan M. Piwowar, Nicholas P. Lockyer, John C. VickermanAbstract:Abstract In secondary Ion mass spectrometry, Polyatomic primary Ion sources are known to enhance yields from many surfaces including polymers. In order to understand the fundamental causes for these increases, the enhancement as a functIon of material type and molecular weight needs to be delineated. In this article, we report results from a systematic investigatIon of polymeric films of polystyrene (PS) with varying molecular weights to examine the influence of the primary Ion beam on the secondary Ion yields in time of flight secondary Ion mass spectrometry (ToF-SIMS). The masses of the polymers investigated ranged from 1000 to 20,000 Da, or from about n = 10 to 200 where n indicates the number of polymeric units in a polymer chain. The polymers had a narrow molecular weight range (PDI + and C 60 + primary Ion beams. The analysis with the two beams provided a useful comparison between atomic and Polyatomic primary Ion sources. InformatIon gathered from this study provides insight into the role of molecular weight on the observed yield enhancement from Polyatomic Ion sources.
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Mass spectral analysis and imaging of tissue by ToF-SIMS—The role of buckminsterfullerene, C60+, primary Ions
International Journal of Mass Spectrometry, 2007Co-Authors: Emrys A Jones, Nicholas P. Lockyer, John C. VickermanAbstract:Abstract Recent developments in desorptIon/IonisatIon mass spectrometry techniques have made their applicatIon to biological analysis a realistic and successful propositIon. Developments in primary Ion source technology, mainly through the advent of Polyatomic Ion beams, have meant that the technique of secondary Ion mass spectrometry (SIMS) can now access the depths of informatIon required to allow biological imaging to be a viable optIon. Here the role of the primary Ion C 60 + is assessed with regard to molecular imaging of lipids and pharmaceuticals within tissue sectIons. High secondary Ion yields and low surface damage accumulatIon are demonstrated on both model and real biological samples, indicating the high secondary Ion efficiency afforded to the analyst by this primary Ion when compared to other cluster Ion beams used in imaging. The newly developed 40 keV C 60 + Ion source allows the beam to be focused such that high resolutIon imaging is demonstrated on a tissue sample, and the greater yields allow the molecular signal from the drug raclopride to be imaged within tissue sectIon following in vivo dosing. The localisatIon shown for this drug alludes to issues regarding the chemical environment affecting the IonisatIon probability of the molecule; the importance of this effect is demonstrated with model systems and the possibility of using laser post-IonisatIon as a method for reducing this consequence of bio-sample complexity is demonstrated and discussed.
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c60 buckminsterfullerene its impact on biological tof sims analysis
Surface and Interface Analysis, 2006Co-Authors: John S. Fletcher, Nicholas P. Lockyer, John C. VickermanAbstract:The desire to apply the analytical abilities of the time-of-flight secondary Ion mass spectrometry (ToF-SIMS) experiment to increasingly diverse samples, particularly those of a biological nature, has provided the impetus for development of new technologies to overcome some of the inherent difficulties associated with such studies. Of these, one of the most important is the widespread introductIon of Polyatomic Ion beams to increase the secondary Ion yields of the higher mass, more chemically characteristic species. The introductIon of the C-60 Ion beam for routine analysis has made arguably the greatest impact, providing new possibilities for analysing molecular compounds present both on the surface and in some cases in the bulk of samples such as biological tissue sectIons and single cells. Copyright (C) 2006 John Wiley & Sons, Ltd.
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Molecular depth profiling of organic and biological materials
Applied Surface Science, 2006Co-Authors: John S. Fletcher, Nicholas P. Lockyer, Xavier A. Conlan, John C. VickermanAbstract:Atomic depth profiling using secondary Ion mass spectrometry, SIMS, is common in the field micro-electronics; however, the generatIon of molecular informatIon as a functIon of sample depth is difficult due to the accumulatIon of damage both on and beneath the sample surface. The introductIon of Polyatomic Ion beams such as SF5 and C60 have raised the possibility of overcoming this problem as they deposit the majority of their energy in the upper surface of the sample resulting in increased sputter yields but with a complimentary reductIon in sub-surface damage accumulatIon. In this paper we report the depth profile analysis of the bio-polymer polycaprolactone, PCL, using the Polyatomic Ions Au3+ and C60+ and the monoatomic Au+. Results are compared to recent analysis of a similar sample using SF5+. C60+ depth profiling of cellulose is also demonstrated, an experiment that has been reported as unsuccessful when attempted with SF5+ implicatIons for biological analysis are discussed.
Luke Hanley - One of the best experts on this subject based on the ideXlab platform.
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A comparison of Polyatomic Ion deposited, RF magnetron sputtered and plasma polymer organosilicon films
Thin Solid Films, 2005Co-Authors: Andrei Choukourov, Andrey Grinevich, Jan Hanuš, Jaroslav Kousal, Danka Slavínská, Hynek Biederman, A. Bowers, Luke HanleyAbstract:In this work organosilicon films are prepared by plasma polymerizatIon and mass-selected Polyatomic Ion depositIon (MS-PID) of divinyltetramethyldisilazane, and by rf magnetron sputtering of polydimethylsiloxane. The compositIon of coatings is determined by XPS and FTIR. A chemical derivatizatIon method is applied to detect amines in silazane films. Plasma polymers and Ion deposited films are found to be more organic; whereas magnetron sputtered coatings are dominated by SiO x species. Plasma polymers are deficient of nitrogen with silicon bound in various Si x C y O z species. Silicon in PID-films is bound mainly to nitrogen (Si,N). The processes of aging in air or in water are also discussed.
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growth of primary and secondary amine films from Polyatomic Ion depositIon
Vacuum, 2004Co-Authors: Andrei Choukourov, Jaroslav Kousal, Erick R. Fuoco, D Slavinska, H Biederman, Sanja Tepavcevic, Juan Saucedo, Luke HanleyAbstract:Abstract Amine-containing organic films are deposited onto silicon substrates from mass-selected beams of 5–200 eV Si2NC8H19+ (silazane) and 15–100 eV C3H6N+ (allylamine) Ions produced by electron impact IonizatIon of 1,3-divinyltetramethyldisilazane and allylamine. Silazane films are also deposited onto aluminum substrates. These Ion-deposited films are analysed directly and/or after air exposure by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Chemical derivatizatIon prior to XPS analysis is utilized to distinguish primary and secondary amine groups in the films from non-amine nitrogen. Primary amines are absent in silazane films. Secondary amine containing films form at low silazane Ion energies whereas the higher Ion energies lead to formatIon of more inorganic, silico-carbo-nitride-like films. The Ion energy trend is similar for films from allylamine Ions, except for the fact that both primary and secondary amines are detected. The primary amines from allylamine Ions survive film ageing in air for periods of several days. Ion-induced film-substrate reactIons are observed for silazane films.
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Controlling the nanoscale morphology of organic films deposited by Polyatomic Ions
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2003Co-Authors: Luke Hanley, Muthu B. J. Wijesundara, Erick R. Fuoco, Yongsoo Choi, F. Ahu Akin, Aleksey M. Tikhonov, Mark L. SchlossmanAbstract:Abstract Hyperthermal Polyatomic Ion beams can be used to fabricate thin film nanostructures with controlled morphology. Several experiments are described in which mass-selected and non-mass-selected Polyatomic Ion beams are used to create nanometer thick films with controlled surface and buried interface morphologies. Fluorocarbon and thiophenic films are grown on silicon wafers and/or polystyrene from 5 to 200 eV C3F5+ or C4H4S+ Ions, respectively. X-ray photoelectron spectroscopy, atomic force microscopy, X-ray reflectivity, and scanning electron microscopy are utilized to analyze the morphology and chemistry of these films. Polyatomic Ions are found to control film morphology on the nanoscale through variatIon of the incident Ion energy, Ion structure and/or substrate.
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the effect of Ion energy on the chemistry of air aged polymer films grown from the hyperthermal Polyatomic Ion si2ome5
Journal of Electron Spectroscopy and Related Phenomena, 2001Co-Authors: Pat N Brookes, Luke Hanley, Erick R. Fuoco, Stuart Fraser, Robert D Short, Adam Roberts, Simon HuttonAbstract:Abstract Thin polymer films have been grown from hyperthermal [m/z 147, Si2OMe5+] Ions, using Ion energies of 15, 25, 50, and 100 eV. X-ray photoelectron spectroscopy (XPS) and secondary Ion mass spectrometry (SIMS) analyses were undertaken of the air-aged polymer films. The SIMS and XPS of samples deposited from Ion beams of 15 and 25 eV energies (15 and 25 eV polymers) are remarkably similar, but different in a number of respects to those of the 50 and 100 eV polymers. The positive SIMS of the lower energy polymers resemble closely that of the linear polymer polydimethyl siloxane (PDMS). However, the XPS of these polymers reveal a range of silicon binding environments [Si–C/H, Si(–O1) Si(–O2) (Si–O3) and Si(–O4)], whilst the ‘monomer Ion’ (m/z 147) has only one, Si(–O1). Although the positive Ion SIMS of the 50 and 100 eV polymers contain ‘PDMS-like’ fragments (m/z 147, 207, 221, 281), these Ions are much reduced in intensity (cf. 15 and 25 eV), and we postulate that the extent of cross-linking is much higher in these polymers. In fitting the XPS of these polymers it was necessary to include an additIonal component peak for Si(–Si3). These polymers are compared with a low power plasma polymer of HMDSO. The polymers grown from the 15 and 25 eV Ions are remarkably similar to the plasma polymer in terms of their molecular structure and their surface chemistry.
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surface analysis studies of yield enhancements in secondary Ion mass spectrometry by Polyatomic projectiles
Journal of Physical Chemistry B, 2001Co-Authors: Erick R. Fuoco, Muthu B. J. Wijesundara, Greg Gillen, William E Wallace, Luke HanleyAbstract:In this paper we examine the mechanism of secondary Ion yield enhancements previously observed for Polyatomic projectiles by measuring the weight loss, volume loss, and surface compositIon of poly(methyl methacrylate) (PMMA) films sputtered by keV SF5+ and Ar+ projectile Ions. The sputter yieldthe amount of material removed from the surface by 3.0 keV SF5+ projectileswas found to be 2.2 ± 0.8 higher than for Ar+ projectiles, measured by weight loss in the PMMA film with a quartz crystal microbalance. This result is consistent with sputter yield measurements reported here using 5.5 keV Ions and stylus profilometry. Thus, the >10× enhancement in secondary Ion yield in secondary Ion mass spectrometry observed for Polyatomic Ion projectiles is not attributable to the modest ∼2× enhancements observed in the sputter yields for this molecular solid. Surface chemical measurements by X-ray photoelectron spectroscopy also indicated fundamental differences in atomic versus Polyatomic sputtering mechanisms at 3.0 keV...
I V Veryovkin - One of the best experts on this subject based on the ideXlab platform.
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new cs sputter Ion source with Polyatomic Ion beams for secondary Ion mass spectrometry applicatIons
Review of Scientific Instruments, 2007Co-Authors: S.f. Belykh, I V Veryovkin, Annemie Adriaens, Vladimir Palitsin, A P Kovarsky, R J H Chang, M G Dowsett, F AdamsAbstract:A simple design for a cesium sputter Ion source compatible with vacuum and Ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This Ion source has been tested with the cluster primary Ions of Sin− and Cun−. Our experiments with surface characterizatIon and depth profiling conducted to date demonstrate improvements of the analytical capabilities of the secondary Ion mass spectrometry instrument due to the nonadditive enhancement of secondary Ion emissIon and shorter Ion ranges of Polyatomic projectiles compared to atomic ones with the same impact energy.
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on the trends in kinetic energies of secondary Ions produced by Polyatomic Ion bombardment
Applied Surface Science, 2004Co-Authors: I V Veryovkin, S.f. Belykh, Annemie Adriaens, A V Zinovev, Freddy AdamsAbstract:Kinetic energies of Tan þ and Nbn þ Ions (1 � n � 10) sputtered from pure Ta and Nb targets by 6 keV per atom Au � ,A u2 � and Au3 � primary Ions have been compared after energy spectra of these Ions were recalibrated using a newly developed data processing algorithm. Most probable and mean energies were determined for the sputtered Ions, and their energy spectra were converted into distributIons over inverse velocities. DistributIons obtained for Ta and Nb displayed many similarities and no principal differences. The only differences seen were due to the difference in masses of the elements. On the other hand, strong differences were observed between results for atomic and diatomic sputtered Ions and those for larger sputtered cluster Ions (with more than seven atoms). The comparison of atomic and Polyatomic bombardment showed dramatic changes in emissIon of atomic and diatomic sputtered species, and almost no differences for larger sputtered clusters. # 2004 Elsevier B.V. All rights reserved.
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Sputtering with Polyatomic Ions: revisiting kinetic energy distributIons of secondary Ions
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2004Co-Authors: I V Veryovkin, S.f. Belykh, Annemie Adriaens, F AdamsAbstract:Anew more accurate data processing procedure for calibratIon of kinetic energies of secondary Ions measured in magnetic sector secondary Ion mass spectrometers has been developed. The procedure was applied to reprocessing of raw data from previously published measurements of kinetic energy spectra of secondary atomic and cluster Ions sputtered from Ta by 6 keV/atom Au � ,Auand Auprojectiles. Absolute energies of the sputtered Ta þ Ions were determined more accurately, which permitted a fairer comparison of energy spectra for the same secondary Ions measured under bombardment with different primary Ions. Most probable and mean energies were determined for the sputtered Ions, and their energy spectra were converted into distributIons over inverse velocities. The reprocessed experimental results revealed strong differences between results for atomic and diatomic Ions and those for larger cluster Ions (consisting of more than seven atoms). In particular, the comparison of atomic and Polyatomic bombardment showed that there are strong differences between atomic and diatomic sputtered species, while there were almost no changes between larger sputtered clusters. Results are discussed in terms of observed enhancements under Polyatomic Ion bombardment for the total sputtering efficiency and the IonizatIon of sputtered species.
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Sputtering with Polyatomic Ions: revisiting kinetic energy distributIons of secondary Ions
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004Co-Authors: I V Veryovkin, S.f. Belykh, Annemie Adriaens, F AdamsAbstract:Abstract: A new more accurate data processing procedure for calibratIon of kinetic energies of secondary Ions measured in magnetic sector secondary Ion mass spectrometers has been developed. The procedure was applied to reprocessing of raw data from previously published measurements of kinetic energy spectra of secondary atomic and cluster Ions sputtered from Ta by 6 keV/atom Au(-), Au(2)(-) and Au(3)(-) projectiles. Absolute energies of the sputtered Ta Ions were determined more accurately, which permitted a fairer comparison of energy spectra for the same secondary Ions measured under bombardment with different primary Ions. Most probable and mean energies were determined for the sputtered Ions, and their energy spectra were converted into distributIons over inverse velocities. The reprocessed experimental results revealed strong differences between results for atomic and diatomic Ions and those for larger cluster Ions (consisting of more than seven atoms). In particular, the comparison of atomic and Polyatomic bombardment showed that there are strong differences between atomic and diatomic sputtered species, while there were almost no changes between larger sputtered clusters. Results are discussed in terms of observed enhancements under Polyatomic Ion bombardment for the total sputtering efficiency and the IonizatIon of sputtered species. (C) 2004 Elsevier B.V. All rights reserved
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relative yields mass distributIons and energy spectra of cluster Ions sputtered from niobium under kev atomic and Polyatomic gold Ion bombardment
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2000Co-Authors: S.f. Belykh, L.v Stroev, B Habets, Kh U Rasulev, A V Samartsev, I V VeryovkinAbstract:Abstract In the present work, the comparative studies of relative yields, mass distributIons and kinetic energy spectra of secondary Nbn+ Ions (n=1–16) sputtered from niobium target by atomic and Polyatomic Aum− projectiles (m = 1–3) with the energy E0 = 6–18 keV/atom have been carried out. The strong effect of anomalously high non-additivity of metal sputtering as positive large cluster Ions under Polyatomic Ion bombardment was found. The comparison and discussIon of the results obtained for Nb and for Ta are presented.
Nicholas P. Lockyer - One of the best experts on this subject based on the ideXlab platform.
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tof sims with argon gas cluster Ion beams a comparison with c60
Analytical Chemistry, 2011Co-Authors: Sadia Rabbani, John S. Fletcher, Nicholas P. Lockyer, Andrew M Barber, John C. VickermanAbstract:Time-of-flight secondary Ion mass spectrometry (TOF-SIMS) is an established technique for the characterizatIon of solid sample surfaces. The introductIon of Polyatomic Ion beams, such as C60, has provided the associated ability to perform molecular depth-profiling and 3D molecular imaging. However, not all samples perform equally under C60 bombardment, and it is probably naive to think that there will be an Ion beam that will be applicable in all situatIons. It is therefore important to explore the potential of other candidates. A systematic study of the suitability of argon gas cluster Ion beams (Ar-GCIBs) of general compositIon Arn+, where n = 60–3000, as primary particles in TOF-SIMS analysis has been performed. We have assessed the potential of the Ar-GCIBs for molecular depth-profiling in terms of damage accumulatIon and sputter rate and also as analysis beams where spectral quality and secondary Ion yields are considered. We present results with direct comparison with C60 Ions on the same sample in ...
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InvestigatIon of molecular weight effects of polystyrene in ToF-SIMS using C60+ and Au+ primary Ion beams
Applied Surface Science, 2008Co-Authors: Alan M. Piwowar, Nicholas P. Lockyer, John C. VickermanAbstract:Abstract In secondary Ion mass spectrometry, Polyatomic primary Ion sources are known to enhance yields from many surfaces including polymers. In order to understand the fundamental causes for these increases, the enhancement as a functIon of material type and molecular weight needs to be delineated. In this article, we report results from a systematic investigatIon of polymeric films of polystyrene (PS) with varying molecular weights to examine the influence of the primary Ion beam on the secondary Ion yields in time of flight secondary Ion mass spectrometry (ToF-SIMS). The masses of the polymers investigated ranged from 1000 to 20,000 Da, or from about n = 10 to 200 where n indicates the number of polymeric units in a polymer chain. The polymers had a narrow molecular weight range (PDI + and C 60 + primary Ion beams. The analysis with the two beams provided a useful comparison between atomic and Polyatomic primary Ion sources. InformatIon gathered from this study provides insight into the role of molecular weight on the observed yield enhancement from Polyatomic Ion sources.
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Mass spectral analysis and imaging of tissue by ToF-SIMS—The role of buckminsterfullerene, C60+, primary Ions
International Journal of Mass Spectrometry, 2007Co-Authors: Emrys A Jones, Nicholas P. Lockyer, John C. VickermanAbstract:Abstract Recent developments in desorptIon/IonisatIon mass spectrometry techniques have made their applicatIon to biological analysis a realistic and successful propositIon. Developments in primary Ion source technology, mainly through the advent of Polyatomic Ion beams, have meant that the technique of secondary Ion mass spectrometry (SIMS) can now access the depths of informatIon required to allow biological imaging to be a viable optIon. Here the role of the primary Ion C 60 + is assessed with regard to molecular imaging of lipids and pharmaceuticals within tissue sectIons. High secondary Ion yields and low surface damage accumulatIon are demonstrated on both model and real biological samples, indicating the high secondary Ion efficiency afforded to the analyst by this primary Ion when compared to other cluster Ion beams used in imaging. The newly developed 40 keV C 60 + Ion source allows the beam to be focused such that high resolutIon imaging is demonstrated on a tissue sample, and the greater yields allow the molecular signal from the drug raclopride to be imaged within tissue sectIon following in vivo dosing. The localisatIon shown for this drug alludes to issues regarding the chemical environment affecting the IonisatIon probability of the molecule; the importance of this effect is demonstrated with model systems and the possibility of using laser post-IonisatIon as a method for reducing this consequence of bio-sample complexity is demonstrated and discussed.
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c60 buckminsterfullerene its impact on biological tof sims analysis
Surface and Interface Analysis, 2006Co-Authors: John S. Fletcher, Nicholas P. Lockyer, John C. VickermanAbstract:The desire to apply the analytical abilities of the time-of-flight secondary Ion mass spectrometry (ToF-SIMS) experiment to increasingly diverse samples, particularly those of a biological nature, has provided the impetus for development of new technologies to overcome some of the inherent difficulties associated with such studies. Of these, one of the most important is the widespread introductIon of Polyatomic Ion beams to increase the secondary Ion yields of the higher mass, more chemically characteristic species. The introductIon of the C-60 Ion beam for routine analysis has made arguably the greatest impact, providing new possibilities for analysing molecular compounds present both on the surface and in some cases in the bulk of samples such as biological tissue sectIons and single cells. Copyright (C) 2006 John Wiley & Sons, Ltd.
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Molecular depth profiling of organic and biological materials
Applied Surface Science, 2006Co-Authors: John S. Fletcher, Nicholas P. Lockyer, Xavier A. Conlan, John C. VickermanAbstract:Atomic depth profiling using secondary Ion mass spectrometry, SIMS, is common in the field micro-electronics; however, the generatIon of molecular informatIon as a functIon of sample depth is difficult due to the accumulatIon of damage both on and beneath the sample surface. The introductIon of Polyatomic Ion beams such as SF5 and C60 have raised the possibility of overcoming this problem as they deposit the majority of their energy in the upper surface of the sample resulting in increased sputter yields but with a complimentary reductIon in sub-surface damage accumulatIon. In this paper we report the depth profile analysis of the bio-polymer polycaprolactone, PCL, using the Polyatomic Ions Au3+ and C60+ and the monoatomic Au+. Results are compared to recent analysis of a similar sample using SF5+. C60+ depth profiling of cellulose is also demonstrated, an experiment that has been reported as unsuccessful when attempted with SF5+ implicatIons for biological analysis are discussed.
Didier Léonard - One of the best experts on this subject based on the ideXlab platform.
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fragmentatIon of molecular compounds on silicon wafers and low dielectric constant materials studied by time of flight secondary Ion mass spectrometry using a Polyatomic Ion source
Surface and Interface Analysis, 2008Co-Authors: X. Ravanel, C. Trouiller, Marc Juhel, C. Wyon, L. F. T. Kwakman, Didier LéonardAbstract:Recent time-of-flight secondary Ion mass spectrometry (ToF-SIMS) studies using primary cluster Ion sources such as Au n + , SF n + , Bi n + or C 60 + have shown Polyatomic Ions to be more appropriate for the detectIon of high mass molecular secondary Ions than monoatomic Ion sources like Ga + , thanks to secondary Ion yield and Ion formatIon efficiency enhancements. This work is part of a study aiming at improving molecular compound quantificatIon at the surface of microelectronics industry substrates by taking advantage of a Polyatomic Ion source in ToF-SIMS analysis. It focuses on the case of a phthalate-related contaminatIon. Fundamental parameters like secondary Ion yield, damage cross sectIon and secondary Ion efficiency were studied as a functIon of the size and the energy of the primary Ions. The substrate compositIon influence on the ToF-SIMS results was also studied by comparing several substrates of interest in the microelectronics industry such as silicon wafers and low dielectric constant materials 5iO x CyH z . Phthalate-related secondary Ions detected at the surface of the contaminated surfaces were compared and a fragmentatIon pathway of the di-isononyl phthalate (DNP) molecule was determined. A drastic improvement of the secondary Ion yield was provided when using a Polyatomic Ion source. Furthermore, a clear increase in damage cross sectIon was observed as a functIon of the secondary Ion size for a given Bi n primary Ion as well as an increase for a given fragment as a functIon of the number of Bi atoms in the Bi n aggregate. This led to a lower static limit when taking into account higher phthalate fragments and primary Ions of larger size.
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FragmentatIon of molecular compounds on silicon wafers and low dielectric constant materials studied by time‐of‐flight secondary Ion mass spectrometry using a Polyatomic Ion source
Surface and Interface Analysis, 2008Co-Authors: X. Ravanel, C. Trouiller, Marc Juhel, C. Wyon, L. F. T. Kwakman, Didier LéonardAbstract:Recent time-of-flight secondary Ion mass spectrometry (ToF-SIMS) studies using primary cluster Ion sources such as Au n + , SF n + , Bi n + or C 60 + have shown Polyatomic Ions to be more appropriate for the detectIon of high mass molecular secondary Ions than monoatomic Ion sources like Ga + , thanks to secondary Ion yield and Ion formatIon efficiency enhancements. This work is part of a study aiming at improving molecular compound quantificatIon at the surface of microelectronics industry substrates by taking advantage of a Polyatomic Ion source in ToF-SIMS analysis. It focuses on the case of a phthalate-related contaminatIon. Fundamental parameters like secondary Ion yield, damage cross sectIon and secondary Ion efficiency were studied as a functIon of the size and the energy of the primary Ions. The substrate compositIon influence on the ToF-SIMS results was also studied by comparing several substrates of interest in the microelectronics industry such as silicon wafers and low dielectric constant materials 5iO x CyH z . Phthalate-related secondary Ions detected at the surface of the contaminated surfaces were compared and a fragmentatIon pathway of the di-isononyl phthalate (DNP) molecule was determined. A drastic improvement of the secondary Ion yield was provided when using a Polyatomic Ion source. Furthermore, a clear increase in damage cross sectIon was observed as a functIon of the secondary Ion size for a given Bi n primary Ion as well as an increase for a given fragment as a functIon of the number of Bi atoms in the Bi n aggregate. This led to a lower static limit when taking into account higher phthalate fragments and primary Ions of larger size.
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Static time-of-flight secondary Ion mass spectrometry analysis of microelectronics related substrates using a Polyatomic Ion source
Applied Surface Science, 2008Co-Authors: X. Ravanel, C. Trouiller, Marc Juhel, C. Wyon, L. F. T. Kwakman, Didier LéonardAbstract:Abstract Recent time-of-flight secondary Ion mass spectrometry studies using primary Ion cluster sources such as Aun+, SF5+, Bin+ or C60+ have shown the great advantages in terms of secondary Ion yield enhancement and Ion formatIon efficiency of Polyatomic Ion sources as compared to monoatomic Ion sources like the commonly used Ga+. In this work, the effective gains provided by such a source in the static ToF-SIMS analysis of microelectronics devices were investigated. Firstly, the influence of the number of atoms in the primary cluster Ion on secondary Ion formatIon was studied for physically adsorbed di-isononyl phthalate (DNP) (plasticizer) and perfluoropolyether (PFPE). A drastic increase in secondary Ion formatIon efficiency and a much lower detectIon limit were observed when using a Polyatomic primary Ion. Moreover, the yield of the higher mass species was much enhanced indicating a lower degree of fragmentatIon that can be explained by the fact that the primary Ion energy is spread out more widely, or that there is a lower energy per incoming Ion. Secondly, the influence of the number of Bi atoms in the Bin primary Ion on the informatIon depth was studied using reference thermally grown silicon oxide samples. The informatIon depth provided by a Bin cluster was shown to be lowered when the number of atoms in the aggregate was increased.