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Jiro Matsuo - One of the best experts on this subject based on the ideXlab platform.

  • peptide fragmentatIon and surface structural analysis by means of tof sims using large Cluster Ion sources
    Analytical Chemistry, 2016
    Co-Authors: Yuta Yokoyama, John C. Vickerman, Nicholas P. Lockyer, John S. Fletcher, Jiro Matsuo, Satoka Aoyagi, Makiko Fujii, Melissa K Passarelli, Rasmus Havelund, M P Seah
    Abstract:

    Peptide or protein structural analysis is crucial for the evaluatIon of biochips and biodevices, therefore an analytical technique with the ability to detect and identify protein and peptide species directly from surfaces with high lateral resolutIon is required. In this report, the efficacy of ToF-SIMS to analyze and identify proteins directly from surfaces is evaluated. Although the physics governing the SIMS bombardment process precludes the ability for researchers to detect intact protein or larger peptides of greater than a few thousand mass unit directly, it is possible to obtain informatIon on the partial structures of peptides or proteins using low energy per atom argon Cluster Ion beams. Large Cluster Ion beams, such as Ar Clusters and C60 Ion beams, produce spectra similar to those generated by tandem MS. The SIMS bombardment process also produces peptide fragment Ions not detected by conventIonal MS/MS techniques. In order to clarify appropriate measurement conditIons for peptide structural ana...

  • progress and applicatIons of Cluster Ion beam technology
    Current Opinion in Solid State & Materials Science, 2015
    Co-Authors: I Yamada, Jiro Matsuo, Takaaki Aoki, Noriaki Toyoda, Toshio Seki
    Abstract:

    Abstract Cluster Ion beam processing has been extensively developed during the 25 years since the concept originated. Low energy surface interactIon effects, lateral sputtering phenomena and high-rate chemical reactIon effects have been explored experimentally and have been explained by means of molecular dynamics (MD) modeling. Practical productIon equipment for a wide range of applicatIons has also been successfully developed. The technology is now advancing rapidly in the fields of sub-nanoscale processing of metals, semiconductors and insulating materials. This paper reviews important events which have taken place during the development with emphasis placed on emerging new advances which have occurred during several recent years.

  • Etching of metallic materials with Cl2 gas Cluster Ion beam
    Surface & Coatings Technology, 2011
    Co-Authors: Toshio Seki, Takaaki Aoki, Jiro Matsuo
    Abstract:

    Abstract Cluster Ion beam processes exhibit high rate sputtering with low damage, and in particular, extremely high sputtering rates are expected using reactive Cluster Ion beams. Si could be sputtered at extremely high rates using reactive Cluster Ion beams, such as SF 6 , Cl 2 , CF 4 , CHF 3 , and CH 2 F 2 . However, processing of metallic materials with reactive Cluster Ion beams has not been studied yet. It was expected that high-speed etching of metallic materials can be realized with Cl 2 Cluster Ion irradiatIon, because such a beam would reactively sputter these materials. We generated a Cl 2 Cluster Ion beam and investigated the etching characteristics of various metallic materials, such as Ni and Al films, under this irradiatIon. The size of the Cl 2 Cluster, as measured with a time-of-flight (TOF) system, was about 1400 molecules. The sputtering yield for each metal was more than 10 times higher than that obtained with Ar Cluster Ions, showing that Cl 2 Cluster Ion irradiatIon reactively sputtered the metallic materials. These results indicated that Cl 2 Cluster Ion irradiatIon was suitable for high-speed processing of metallic materials.

  • molecular dynamics simulatIons for gas Cluster Ion beam processes
    Vacuum, 2010
    Co-Authors: Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    Molecular dynamics (MD) simulatIons of large argon Clusters impacting on silicon targets were performed. The characteristics of crater formatIon, a typical collisIonal effect with large Cluster impact were examined from the viewpoint of incident energy, Cluster size and incident angle. The MD simulatIon results suggested that the conditIon where an incident Cluster penetrates into the solid target and causes a crater is mainly dominated by the incident energy-per-atom rather than total incident energy of the Cluster. AdditIonally, the MD simulatIons of sequential multiple Cluster impacts and grazing-angle Cluster irradiatIon on irregular surface structures were studied to characterize the surface modificatIon effects with large Cluster Ion beam process.

  • molecular depth profiling of multilayer structures of organic semiconductor materials by secondary Ion mass spectrometry with large argon Cluster Ion beams
    Rapid Communications in Mass Spectrometry, 2009
    Co-Authors: Satoshi Ninomiya, Kazuya Ichiki, Yoshihiko Nakata, Hideaki Yamada, Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    In this study, we present molecular depth profiling of multilayer structures composed of organic semiconductor materials such as tris(8-hydroxyquinoline)aluminum (Alq3) and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD). Molecular Ions produced from Alq3 and NPD were measured by linear-type time-of-flight (TOF) mass spectrometry under 5.5 keV Ar700 Ion bombardment. The organic multilayer films were analyzed and etched with large Ar Cluster Ion beams, and the interfaces between the organic layers were clearly distinguished. The effect of temperature on the diffusIon of these materials was also investigated by the depth profiling analysis with Ar Cluster Ion beams. The thermal diffusIon behavior was found to depend on the specific materials, and the diffusIon of Alq3 molecules was observed to start at a lower temperature than that of NPD molecules. These results prove the great potential of large gas Cluster Ion beams for molecular depth profiling of organic multilayer samples. Copyright © 2009 John Wiley & Sons, Ltd.

Toshio Seki - One of the best experts on this subject based on the ideXlab platform.

  • progress and applicatIons of Cluster Ion beam technology
    Current Opinion in Solid State & Materials Science, 2015
    Co-Authors: I Yamada, Jiro Matsuo, Takaaki Aoki, Noriaki Toyoda, Toshio Seki
    Abstract:

    Abstract Cluster Ion beam processing has been extensively developed during the 25 years since the concept originated. Low energy surface interactIon effects, lateral sputtering phenomena and high-rate chemical reactIon effects have been explored experimentally and have been explained by means of molecular dynamics (MD) modeling. Practical productIon equipment for a wide range of applicatIons has also been successfully developed. The technology is now advancing rapidly in the fields of sub-nanoscale processing of metals, semiconductors and insulating materials. This paper reviews important events which have taken place during the development with emphasis placed on emerging new advances which have occurred during several recent years.

  • Etching of metallic materials with Cl2 gas Cluster Ion beam
    Surface & Coatings Technology, 2011
    Co-Authors: Toshio Seki, Takaaki Aoki, Jiro Matsuo
    Abstract:

    Abstract Cluster Ion beam processes exhibit high rate sputtering with low damage, and in particular, extremely high sputtering rates are expected using reactive Cluster Ion beams. Si could be sputtered at extremely high rates using reactive Cluster Ion beams, such as SF 6 , Cl 2 , CF 4 , CHF 3 , and CH 2 F 2 . However, processing of metallic materials with reactive Cluster Ion beams has not been studied yet. It was expected that high-speed etching of metallic materials can be realized with Cl 2 Cluster Ion irradiatIon, because such a beam would reactively sputter these materials. We generated a Cl 2 Cluster Ion beam and investigated the etching characteristics of various metallic materials, such as Ni and Al films, under this irradiatIon. The size of the Cl 2 Cluster, as measured with a time-of-flight (TOF) system, was about 1400 molecules. The sputtering yield for each metal was more than 10 times higher than that obtained with Ar Cluster Ions, showing that Cl 2 Cluster Ion irradiatIon reactively sputtered the metallic materials. These results indicated that Cl 2 Cluster Ion irradiatIon was suitable for high-speed processing of metallic materials.

  • molecular dynamics simulatIons for gas Cluster Ion beam processes
    Vacuum, 2010
    Co-Authors: Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    Molecular dynamics (MD) simulatIons of large argon Clusters impacting on silicon targets were performed. The characteristics of crater formatIon, a typical collisIonal effect with large Cluster impact were examined from the viewpoint of incident energy, Cluster size and incident angle. The MD simulatIon results suggested that the conditIon where an incident Cluster penetrates into the solid target and causes a crater is mainly dominated by the incident energy-per-atom rather than total incident energy of the Cluster. AdditIonally, the MD simulatIons of sequential multiple Cluster impacts and grazing-angle Cluster irradiatIon on irregular surface structures were studied to characterize the surface modificatIon effects with large Cluster Ion beam process.

  • molecular depth profiling of multilayer structures of organic semiconductor materials by secondary Ion mass spectrometry with large argon Cluster Ion beams
    Rapid Communications in Mass Spectrometry, 2009
    Co-Authors: Satoshi Ninomiya, Kazuya Ichiki, Yoshihiko Nakata, Hideaki Yamada, Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    In this study, we present molecular depth profiling of multilayer structures composed of organic semiconductor materials such as tris(8-hydroxyquinoline)aluminum (Alq3) and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD). Molecular Ions produced from Alq3 and NPD were measured by linear-type time-of-flight (TOF) mass spectrometry under 5.5 keV Ar700 Ion bombardment. The organic multilayer films were analyzed and etched with large Ar Cluster Ion beams, and the interfaces between the organic layers were clearly distinguished. The effect of temperature on the diffusIon of these materials was also investigated by the depth profiling analysis with Ar Cluster Ion beams. The thermal diffusIon behavior was found to depend on the specific materials, and the diffusIon of Alq3 molecules was observed to start at a lower temperature than that of NPD molecules. These results prove the great potential of large gas Cluster Ion beams for molecular depth profiling of organic multilayer samples. Copyright © 2009 John Wiley & Sons, Ltd.

  • precise and fast secondary Ion mass spectrometry depth profiling of polymer materials with large ar Cluster Ion beams
    Rapid Communications in Mass Spectrometry, 2009
    Co-Authors: Satoshi Ninomiya, Kazuya Ichiki, Yoshihiko Nakata, Hideaki Yamada, Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    We demonstrate depth profiling of polymer materials by using large argon (Ar) Cluster Ion beams. In general, depth profiling with secondary Ion mass spectrometry (SIMS) presents serious problems in organic materials, because the primary keV atomic Ion beams often damage them and the molecular Ion yields decrease with increasing incident Ion fluence. Recently, we have found reduced damage of organic materials during sputtering with large gas Cluster Ions, and reported on the unique secondary Ion emissIon of organic materials. Secondary Ions from the polymer films were measured with a linear type time-of-flight (TOF) technique; the films were also etched with large Ar Cluster Ion beams. The mean Cluster size of the primary Ion beams was Ar 700 and incident energy was 5.5 keV. Although the primary Ion fluence exceeded the static SIMS limit, the molecular Ion intensities from the polymer films remained constant, indicating that irradiatIon with large Ar Cluster Ion beams rarely leads to damage accumulatIon on the surface of the films, and this characteristic is excellently suitable for SIMS depth profiling of organic materials.

Isao Yamada - One of the best experts on this subject based on the ideXlab platform.

  • historical milestones and future prospects of Cluster Ion beam technology
    Applied Surface Science, 2014
    Co-Authors: Isao Yamada
    Abstract:

    Abstract Development of technology for processing of surfaces by means of gas Cluster Ion beams began only about a quarter century ago even though fundamental research related to generatIon of gas Clusters began much earlier. Industrial applicatIons of Cluster Ion beams did not start to be explored until commercial equipment was first introduced to the Ion beam community in around 2000. The technology is now evolving rapidly with industrial equipment being engineered for many diverse surface processing applicatIons which are made possible by the unique characteristics of Cluster-Ion/solid-surface interactIons. In this paper, important historical milestones in Cluster Ion beam development are described. Present activities related to a wide range of industrial applicatIons in semiconductors, magnetic and optical devices, and bio-medical devices are reviewed. Several emerging new advances in Cluster beam applicatIons for the future are also discussed.

  • gas Cluster Ion beam etching under acetic acid vapor for etch resistant material
    Japanese Journal of Applied Physics, 2013
    Co-Authors: Akira Yamaguchi, Noriaki Toyoda, Ryo Hinoura, Kenichi Hara, Isao Yamada
    Abstract:

    Gas Cluster Ion beam (GCIB) etching of etch-resistant materials under acetic acid vapor was studied for development of new manufacturing process of future nonvolatile memory. Etching depths of various etch-resistant materials (Pt, Ru, Ta, CoFe) with acetic acid vapor during O2-GCIB irradiatIons were 1.8–10.7 times higher than those without acetic acid. Also, etching depths of Ru, Ta, CoFe by Ar-GCIB with acetic acid vapor were 2.2–16.1 times higher than those without acetic acid. Even after etching of Pt, smoothing of Pt was realized using O2-GCIB under acetic acid. From XPS and angular distributIon of sputtered Pt, it was shown that PtOx layer was formed on Pt after O2-GCIB irradiatIon. PtOx reacted with acetic acid by GCIB bombardments; as a result, increase of etching depth was observed.

  • Surface Smoothing of Polycrystalline Substrates with Gas Cluster Ion Beams
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Takafumi Mashita, Noriaki Toyoda, Isao Yamada
    Abstract:

    The surface smoothing of polycrystalline materials is difficult owing to the etching rate dependence on crystalline orientatIon. In this study, surface smoothing with a gas Cluster Ion beam (GCIB) was studied in polycrystalline substrates such as poly-SiC (surface roughness, 0.3 nm) and yttrium aluminum garnet (YAG; surface roughness, 1.1 nm). Before irradiatIon, there were many scratches induced by mechanical polishing on poly-SiC. These scratches were removed after Ar-GCIB irradiatIon. AdditIonal O2-GCIB irradiatIon for asperity removal showed improvement in the average roughness of poly-SiC to 0.3 nm. Similarly, the scratches on the as-polished surface of YAG disappeared and the YAG surface roughness decreased to 0.7 nm with Ar-GCIB irradiatIon without inducing an etching rate difference between grains. It was also shown that polycrystalline diamond or poly-Si films can be smoothed using GCIB. These results indicate that GCIB polishing is suitable for the surface planarizatIon of polycrystalline materials.

  • planarizatIon of amorphous carbon films on patterned substrates using gas Cluster Ion beams
    Journal of Applied Physics, 2009
    Co-Authors: Noriaki Toyoda, Keisuke Nagato, Hiroshi Tani, Yasuo Sakane, Masayuki Nakao, Tetsuya Hamaguchi, Isao Yamada
    Abstract:

    Surface planarizatIon and modificatIon of a patterned surface were demonstrated using gas Cluster Ion beam (GCIB). Grooves with 100–400 nm intervals were formed on amorphous carbon films using focused Ion beams to study the special frequency dependence of the planarizatIon. Also, line and space patterns were fabricated on Si substrates, and amorphous carbons were deposited as a model structure of discrete track media. Subsequently, surface planarizatIon using Ar-GCIB was carried out. After GCIB irradiatIons, all of the grooves were completely removed, and a flat surface was realized. And it showed that GCIB irradiatIon planarized grooves without huge thickness loss. From the power spectrum density of an atomic force microscope, GCIB preferentially removed grooves with small intervals. It was found from energy dispersive x-ray spectroscopy that surface planarizatIon without severe damage in the amorphous carbon and magnetic layers was carried out with GCIB.

  • Low-energy irradiatIon effects of gas Cluster Ion beams
    Electronics and Communications in Japan, 2008
    Co-Authors: Shingo Houzumi, Noriaki Toyoda, Keigo Takeshima, Kozo Mochiji, Isao Yamada
    Abstract:

    A Cluster-Ion irradiatIon system with Cluster-size selectIon has been developed to study the effects of the Cluster size for surface processes using Cluster Ions. A permanent magnet with a magnetic field of 1.2 T is installed for size separatIon of large Cluster Ions. Trace formatIons at HOPG surface by the irradiatIon with size-selected Ar-Cluster Ions under an acceleratIon energy of 30 keV were investigated by scanning tunneling microscopy. GeneratIon behavior of the craterlike traces is strongly affected by the number of constituent atoms (Cluster size) of the irradiating Cluster Ion. When the incident Cluster Ion is composed of 100 to 3000 atoms, craterlike traces are observed on the irradiated surfaces. In contrast, such traces are not observed at all with the irradiatIon of the Cluster Ions composed of over 5000 atoms. Such behavior is discussed on the basis of the kinetic energy per constituent atom of the Cluster Ion. To study GCIB irradiatIon effects on macromolecules, GCIB was irradiated on DNA molecules absorbed on graphite surface. Using GCIB irradiatIon, many more DNA molecules were sputtered away compared with the monomer-Ion irradiatIon. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(2): 40–45, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10031

Nicholas Winograd - One of the best experts on this subject based on the ideXlab platform.

  • gas Cluster Ion beams for secondary Ion mass spectrometry
    Reviews in Analytical Chemistry, 2018
    Co-Authors: Nicholas Winograd
    Abstract:

    Gas Cluster Ion beams (GCIBs) provide new opportunities for bioimaging and molecular depth profiling with secondary Ion mass spectrometry (SIMS). These beams, consisting of Clusters containing thousands of particles, initiate desorptIon of target molecules with high yield and minimal fragmentatIon. This review emphasizes the unique opportunities for implementing these sources, especially for bioimaging applicatIons. Theoretical aspects of the Cluster Ion/solid interactIon are developed to maximize conditIons for successful mass spectrometry. In additIon, the history of how GCIBs have become practical laboratory tools is reviewed. Special emphasis is placed on the versatility of these sources, as size, kinetic energy, and chemical compositIon can be varied easily to maximize lateral resolutIon, hopefully to less than 1 micron, and to maximize IonizatIon efficiency. Recent examples of bioimaging applicatIons are also presented.

  • CO_2 Cluster Ion Beam, an Alternative Projectile for Secondary Ion Mass Spectrometry
    Journal of The American Society for Mass Spectrometry, 2016
    Co-Authors: Hua Tian, Z Postawa, Barbara J Garrison, Dawid Maciążek, Nicholas Winograd
    Abstract:

    The emergence of argon-based gas Cluster Ion beams for SIMS experiments opens new possibilities for molecular depth profiling and 3D chemical imaging. These beams generally leave less surface chemical damage and yield mass spectra with reduced fragmentatIon compared with smaller Cluster projectiles. For nanoscale bioimaging applicatIons, however, limited sensitivity due to low IonizatIon probability and technical challenges of beam focusing remain problematic. The use of gas Cluster Ion beams based upon systems other than argon offer an opportunity to resolve these difficulties. Here we report on the prospects of employing CO_2 as a simple alternative to argon. IonizatIon efficiency, chemical damage, sputter rate, and beam focus are investigated on model compounds using a series of CO_2 and Ar Cluster projectiles (Cluster size 1000–5000) with the same mass. The results show that the two projectiles are very similar in each of these aspects. Computer simulatIons comparing the impact of Ar_2000 and (CO_2)_2000 on an organic target also confirm that the CO_2 molecules in the Cluster projectile remain intact, acting as a single particle of m/z 44. The imaging resolutIon employing CO_2 Cluster projectiles is improved by more than a factor of two. The advantage of CO_2 versus Ar is also related to the increased stability which, in additIon, facilitates the operatIon of the gas Cluster Ion beams (GCIB) system at lower backing pressure. Graphical Abstract ᅟ

  • co2 Cluster Ion beam an alternative projectile for secondary Ion mass spectrometry
    Journal of the American Society for Mass Spectrometry, 2016
    Co-Authors: Hua Tian, Dawid Maciązek, Z Postawa, Barbara J Garrison, Nicholas Winograd
    Abstract:

    The emergence of argon-based gas Cluster Ion beams for SIMS experiments opens new possibilities for molecular depth profiling and 3D chemical imaging. These beams generally leave less surface chemical damage and yield mass spectra with reduced fragmentatIon compared with smaller Cluster projectiles. For nanoscale bioimaging applicatIons, however, limited sensitivity due to low IonizatIon probability and technical challenges of beam focusing remain problematic. The use of gas Cluster Ion beams based upon systems other than argon offer an opportunity to resolve these difficulties. Here we report on the prospects of employing CO2 as a simple alternative to argon. IonizatIon efficiency, chemical damage, sputter rate, and beam focus are investigated on model compounds using a series of CO2 and Ar Cluster projectiles (Cluster size 1000–5000) with the same mass. The results show that the two projectiles are very similar in each of these aspects. Computer simulatIons comparing the impact of Ar2000 and (CO2)2000 on an organic target also confirm that the CO2 molecules in the Cluster projectile remain intact, acting as a single particle of m/z 44. The imaging resolutIon employing CO2 Cluster projectiles is improved by more than a factor of two. The advantage of CO2 versus Ar is also related to the increased stability which, in additIon, facilitates the operatIon of the gas Cluster Ion beams (GCIB) system at lower backing pressure.

  • Molecular Depth Profiling with Argon Gas Cluster Ion Beams
    The Journal of Physical Chemistry C, 2015
    Co-Authors: Kan Shen, Andreas Wucher, Nicholas Winograd
    Abstract:

    Argon gas Cluster Ion beams (Ar-GCIBs) are remarkable new projectiles for secondary Ion mass spectrometry (SIMS) depth profiling of organic materials. However, the optimal Cluster size and kinetic energy to provide the best quality of depth profiles, in terms of high IonizatIon efficiency of the target molecules, little chemical damage, and short experiment time, for organic materials is not fully understood. Hence, the effect of Cluster size and kinetic energy on the quality of molecular depth profiling is investigated on a simple platform composed of trehalose thin films to acquire more fundamental informatIon about the Ion/solid interactIon. The results suggest that the sputter yield (Y/n) of argon Clusters is linearly dependent upon kinetic energy per atom (E/n). When E/n > 5 eV/atom, normal depth profiles are obtained with relatively high sputter yields. When E/n ≤ 5 eV/atom, however, distorted depth profiles in the steady state regIon are observed, which exhibit a low sputter yield and variable Ioni...

  • a mixed Cluster Ion beam to enhance the IonizatIon efficiency in molecular secondary Ion mass spectrometry
    Rapid Communications in Mass Spectrometry, 2014
    Co-Authors: A Wucher, Hua Tian, Nicholas Winograd
    Abstract:

    RATIonALE: Chemical modificatIon of a rare gas Cluster Ion beam (GCIB) to increase the intensity of desorbed molecular Ions in secondary Ion mass spectrometry experiments relative to the pure Ar Cluster. METHODS: Doping of the GCIB by mixing small concentratIon levels (1–3% relative partial pressure) of CH4 into the Ar gas driving the Cluster Ion source. RESULTS: Mass spectra measured on a trehalose film using the doped GCIB exhibit enhanced molecular Ion signals. From depth profiling experiments, the results are shown to arise from an increase in the IonizatIon efficiency of the sputtered molecules rather than a change in the sputtering yield of neutral species. CONCLUSIonS: Tuning of the chemistry of mixed Clusters is suggested as a general approach to enhancing the IonizatIon probability of sputtered molecules. Copyright © 2013 John Wiley & Sons, Ltd.

Takaaki Aoki - One of the best experts on this subject based on the ideXlab platform.

  • progress and applicatIons of Cluster Ion beam technology
    Current Opinion in Solid State & Materials Science, 2015
    Co-Authors: I Yamada, Jiro Matsuo, Takaaki Aoki, Noriaki Toyoda, Toshio Seki
    Abstract:

    Abstract Cluster Ion beam processing has been extensively developed during the 25 years since the concept originated. Low energy surface interactIon effects, lateral sputtering phenomena and high-rate chemical reactIon effects have been explored experimentally and have been explained by means of molecular dynamics (MD) modeling. Practical productIon equipment for a wide range of applicatIons has also been successfully developed. The technology is now advancing rapidly in the fields of sub-nanoscale processing of metals, semiconductors and insulating materials. This paper reviews important events which have taken place during the development with emphasis placed on emerging new advances which have occurred during several recent years.

  • Etching of metallic materials with Cl2 gas Cluster Ion beam
    Surface & Coatings Technology, 2011
    Co-Authors: Toshio Seki, Takaaki Aoki, Jiro Matsuo
    Abstract:

    Abstract Cluster Ion beam processes exhibit high rate sputtering with low damage, and in particular, extremely high sputtering rates are expected using reactive Cluster Ion beams. Si could be sputtered at extremely high rates using reactive Cluster Ion beams, such as SF 6 , Cl 2 , CF 4 , CHF 3 , and CH 2 F 2 . However, processing of metallic materials with reactive Cluster Ion beams has not been studied yet. It was expected that high-speed etching of metallic materials can be realized with Cl 2 Cluster Ion irradiatIon, because such a beam would reactively sputter these materials. We generated a Cl 2 Cluster Ion beam and investigated the etching characteristics of various metallic materials, such as Ni and Al films, under this irradiatIon. The size of the Cl 2 Cluster, as measured with a time-of-flight (TOF) system, was about 1400 molecules. The sputtering yield for each metal was more than 10 times higher than that obtained with Ar Cluster Ions, showing that Cl 2 Cluster Ion irradiatIon reactively sputtered the metallic materials. These results indicated that Cl 2 Cluster Ion irradiatIon was suitable for high-speed processing of metallic materials.

  • molecular dynamics simulatIons for gas Cluster Ion beam processes
    Vacuum, 2010
    Co-Authors: Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    Molecular dynamics (MD) simulatIons of large argon Clusters impacting on silicon targets were performed. The characteristics of crater formatIon, a typical collisIonal effect with large Cluster impact were examined from the viewpoint of incident energy, Cluster size and incident angle. The MD simulatIon results suggested that the conditIon where an incident Cluster penetrates into the solid target and causes a crater is mainly dominated by the incident energy-per-atom rather than total incident energy of the Cluster. AdditIonally, the MD simulatIons of sequential multiple Cluster impacts and grazing-angle Cluster irradiatIon on irregular surface structures were studied to characterize the surface modificatIon effects with large Cluster Ion beam process.

  • molecular depth profiling of multilayer structures of organic semiconductor materials by secondary Ion mass spectrometry with large argon Cluster Ion beams
    Rapid Communications in Mass Spectrometry, 2009
    Co-Authors: Satoshi Ninomiya, Kazuya Ichiki, Yoshihiko Nakata, Hideaki Yamada, Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    In this study, we present molecular depth profiling of multilayer structures composed of organic semiconductor materials such as tris(8-hydroxyquinoline)aluminum (Alq3) and 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD). Molecular Ions produced from Alq3 and NPD were measured by linear-type time-of-flight (TOF) mass spectrometry under 5.5 keV Ar700 Ion bombardment. The organic multilayer films were analyzed and etched with large Ar Cluster Ion beams, and the interfaces between the organic layers were clearly distinguished. The effect of temperature on the diffusIon of these materials was also investigated by the depth profiling analysis with Ar Cluster Ion beams. The thermal diffusIon behavior was found to depend on the specific materials, and the diffusIon of Alq3 molecules was observed to start at a lower temperature than that of NPD molecules. These results prove the great potential of large gas Cluster Ion beams for molecular depth profiling of organic multilayer samples. Copyright © 2009 John Wiley & Sons, Ltd.

  • precise and fast secondary Ion mass spectrometry depth profiling of polymer materials with large ar Cluster Ion beams
    Rapid Communications in Mass Spectrometry, 2009
    Co-Authors: Satoshi Ninomiya, Kazuya Ichiki, Yoshihiko Nakata, Hideaki Yamada, Takaaki Aoki, Toshio Seki, Jiro Matsuo
    Abstract:

    We demonstrate depth profiling of polymer materials by using large argon (Ar) Cluster Ion beams. In general, depth profiling with secondary Ion mass spectrometry (SIMS) presents serious problems in organic materials, because the primary keV atomic Ion beams often damage them and the molecular Ion yields decrease with increasing incident Ion fluence. Recently, we have found reduced damage of organic materials during sputtering with large gas Cluster Ions, and reported on the unique secondary Ion emissIon of organic materials. Secondary Ions from the polymer films were measured with a linear type time-of-flight (TOF) technique; the films were also etched with large Ar Cluster Ion beams. The mean Cluster size of the primary Ion beams was Ar700 and incident energy was 5.5 keV. Although the primary Ion fluence exceeded the static SIMS limit, the molecular Ion intensities from the polymer films remained constant, indicating that irradiatIon with large Ar Cluster Ion beams rarely leads to damage accumulatIon on the surface of the films, and this characteristic is excellently suitable for SIMS depth profiling of organic materials. Copyright © 2009 John Wiley & Sons, Ltd.