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Hiroshi Yokoyama - One of the best experts on this subject based on the ideXlab platform.

  • characterization of electrical conduction in silicon nanowire by scanning Maxwell Stress microscopy
    Applied Physics Letters, 2001
    Co-Authors: Hideo Fujii, Hiroshi Yokoyama, Takashi Matsukawa, Seigo Kanemaru, Junji Itoh
    Abstract:

    An experimental approach to investigate anomalous electrical conduction in a 100 nm width silicon wire by scanning Maxwell-Stress microscopy (SMM) has been reported. The silicon wire exhibited negative resistance and hysteresis characteristics by sweeping the applied voltage up to 50 V. Potential profile along the wire obtained from the SMM images exhibited that lateral electric field significantly increased at the ground-side end of the wire after the hysteresis characteristics emerged. The field increase is interpreted as the conductivity decrease. The origin of the conductance decrease is considered to be generation and trapping of hot holes at the ground-side end.

  • charging damage of silicon on insulator soi wafer determined by scanning Maxwell Stress microscopy
    Japanese Journal of Applied Physics, 2001
    Co-Authors: Takashi Matsukawa, Hiroshi Yokoyama, Hideo Fujii, Seigo Kanemaru, Masayoshi Nagao, Junji Itoh
    Abstract:

    Charging damage of silicon-on-insulator (SOI) wafer induced by electron-beam (EB) lithography and reactive ion etching (RIE) has been investigated in terms of the surface potential change through the processes. Scanning Maxwell-Stress microscopy (SMM) was utilized for measuring the SOI surface potential under a floating condition. Surface contamination due to resist residues was clearly observed in the SMM potential image. Negative charging of the SOI islands induced by EB lithography was observed particularly under an excessive EB exposure condition and conserved for several days. The cause of the negative charging is considered to be the trapping of electrons in the buried oxide of the SOI wafer.

  • microscopic detection of light induced electron transfer in molecular assembly system using scanning Maxwell Stress microscopy smm
    Electrochimica Acta, 2000
    Co-Authors: Yoshiki Hirata, Fumio Mizutani, Hiroshi Yokoyama
    Abstract:

    Abstract Scanning Maxwell Stress microscopy (SMM), a type of scanning probe microscope capable of imaging the distribution of surface potential over the sample surface, was used to investigate the light induced electron transfer from cyanine dye to viologen moieties embedded in hetero-type Langmuir–Blodgett films. We could observe the light induced surface potential changes upon laser light illumination. Further, the direction of the changes was in accordance with that of the light induced electron transfer in hetero-type LB films.

  • Surface potential imaging of organic and biological samples by using scanning Maxwell-Stress microscopy (SMM)
    Scanning and Force Microscopies for Biomedical Applications, 1999
    Co-Authors: Yoshiki Hirata, Fumio Mizutani, Hiroshi Yokoyama
    Abstract:

    Surface potential measurement on organic thin films and isolated biological samples have been performed using a scanning Maxwell-Stress microscopy (SMM). The SMM is a type of scanning probe microscopy designed to image microscopic electrical properties, such as the local surface potential distribution. The present microscope afforded information of the lateral distribution of molecular dipole moments in phase separated monolayer, and the topographic image of purple membrane fragments as well as dielectric properties of samples.

  • imaging of electrical features in organic thin films by scanning Maxwell Stress microscopy
    Synthetic Metals, 1999
    Co-Authors: Hoonkyu Shin, T Inoue, Youngsoo Kwon, Hiroshi Yokoyama
    Abstract:

    The scanning Maxwell-Stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. Here we report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films prepared by the Langmuir-Blodgett technique.

Takahito Inoue - One of the best experts on this subject based on the ideXlab platform.

  • the relation between corrosion and surface potential measured with the scanning Maxwell Stress microscope
    Nanotechnology, 1998
    Co-Authors: Hiroshi Nanjo, Takahito Inoue, Hiroshi Yokoyama
    Abstract:

    The topographies and the surface potentials on various corroded metal surfaces have been simultaneously measured with the scanning Maxwell Stress microscope to investigate the microscopic relation between the topography of corroded surface and the surface potential in atmosphere. In the early stage of corrosion the potential was low at the corroded region. In the next stage, however, the region where the potential was low at the non-corroded area appeared since anodic region transferred from corroded area to non-corroded area. The microscope is very useful to study the time dependence of the relation between a corroding region and the surface potential.

  • scanning Maxwell Stress microscopy for uhv applications
    Nanotechnology, 1997
    Co-Authors: Takahito Inoue, Junji Itoh, Hiroshi Yokoyama
    Abstract:

    We have developed an easy-to-use electric force microscope for operation in an ultrahigh vacuum (UHV), based on the scanning Maxwell Stress microscope (SMM) for surface science and nanoelectric device applications. The SMM head is built on an UHV flange, with all the optical parts placed on the air side. This design makes our UHV SMM as convenient a system as an instrument operated in air. The performance of UHV SMM is demonstrated for microfabricated silicon surfaces.

  • imaging of surface potential distribution in cyanine dye monolayer by scanning Maxwell Stress microscopy smm
    Molecular Crystals and Liquid Crystals, 1997
    Co-Authors: Yoshiki Hirata, Takahito Inoue, Fumio Mizutani, Tatsuo Katsura, Hiroshi Yokoyama
    Abstract:

    Abstract Scanning Maxwell Stress Microscopy (SMM), which is a type of scanning probe microscopy designed to image microscopic electrical properties, has been applied to cyanine dye Langmuir-Blodgett (LB) monolayers. In combination of epifluorescence microscope technique with SMM, the cyanine J-aggregate formation way was clearly observed. Further the light induced electron transfer between cyanine and viologen in LB film system could be detected as a surface potential change by SMM technique.

  • microscopic characterization of field emitter array structure and work function by scanning Maxwell Stress microscopy
    Journal of Vacuum Science & Technology B, 1996
    Co-Authors: Junji Itoh, Takahito Inoue, Hiroshi Yokoyama, Seigo Kanemaru, Y. Nazuka, Keizo Shimizu
    Abstract:

    Microscopic images of both the structures and surface potential of field emitter arrays were measured by scanning Maxwell‐Stress microscopy (SMM) in air. Results of the SMM measurements clearly showed nanometer‐scale irregularities in the structures and structure‐related surface potential distributions. The surface potential of Si was rather flat even at the emitter tip apex. From these results, the work‐function values for various emitter materials such as Si, Cr, Mo, W, etc. have been derived by using an Au film as the reference material; the work function of Au was assumed to be 5.1 eV. Experimental procedures and results are described in detail.

  • nanoscale evaluation of structure and surface potential of gated field emitters by scanning Maxwell Stress microscope
    Japanese Journal of Applied Physics, 1995
    Co-Authors: Junji Itoh, Takahito Inoue, Hiroshi Yokoyama, Seigo Kanemaru, Y. Nazuka, Keizo Shimizu
    Abstract:

    Both the structural and surface potential images of gated field emitters (GFEs) were measured using a scanning Maxwell-Stress microscope (SMM) in air. Si cone-shaped and Mo disk-edge GFEs were measured. The experimental results clearly revealed differences in the surface potential for various materials and irregularities in the GFE structures which were too small to be found by conventional scanning electron microscope observations. It was also found that the surface potential of Si was rather flat even in the emitter tip apex.

Junji Itoh - One of the best experts on this subject based on the ideXlab platform.

  • doping diagnosis by evaluation of the surface fermi level using scanning Maxwell Stress microscopy
    Applied Physics Letters, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A microscopic approach for evaluation of the Fermi level on the silicon surface under various doping conditions is reported. We have utilized scanning Maxwell-Stress microscopy (SMM) for measurement of the surface potential. The surface Fermi level evaluated by SMM was almost identical to the bulk Fermi level determined by doping when the surface states are passivated by thermal oxide. The SMM measurement on the pn junction under an electrically shorted condition exhibited contrast in potential which is consistent with that of the bulk Fermi level. The results for the open circuit condition exhibited an inconsistent potential profile, which is due to the photovoltaic effect from light irradiation of the sample.

  • silicon nanowire with programmable conductivity analyzed by scanning Maxwell Stress microscopy
    Journal of Vacuum Science & Technology B, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A novel silicon nanowire with programmable conductivity which utilizes sensitivity of conductance to surface charging has been investigated. The device consists of a nanowire with a width of 10–25 nm and side gates for control of surface charging on to the nanowire. The wire current measured during sweep of the side gate exhibited clear hysteresis characteristics and significant retention of the programmed states for more than 1000 s. Surface potential imaging of the nanowire by means of scanning Maxwell-Stress microscopy (SMM) has been carried out for correlating the programmed conductivity to charging on the nanowire. The SMM images clearly exhibited that charging on the nanowire which provided the programmable conductivity was precisely controlled by the side gate sweep.

  • mechanism of tungsten plug corrosion during chemical stripping process scanning Maxwell Stress microscopy and electrochemical potentiometry studies
    Japanese Journal of Applied Physics, 2002
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Yoko Murata, Takeshi Kotani, Junji Itoh
    Abstract:

    Corrosion of W plugs in LSI interconnects during chemical solvent stripping was investigated by scanning Maxwell-Stress microscopy (SMM). The surface potential of TiN, Al and W, of which the interconnects are composed, was measured by SMM, and the changes in electrostatic charging and work functions through the processes were estimated. After immersion in aqueous amine stripper, which actually caused the W plug corrosion, the work functions of the Al and W films were comparable. Due to the similarity of the work function to the electrochemical reduction potential, we consider that the corrosion protection of the Al/W contact becomes inactive in the aqueous amine stripper. This is also supported by the electrode potential measurement in the aqueous amine stripper, for which the Al potential exhibited a higher value than that of W only for the films after O2 ashing. We consider that the W plug corrosion is caused by the electrochemical interaction between the aqueous amine stripper and the material deposited on the Al by O2 ashing.

  • characterization of electrical conduction in silicon nanowire by scanning Maxwell Stress microscopy
    Applied Physics Letters, 2001
    Co-Authors: Hideo Fujii, Hiroshi Yokoyama, Takashi Matsukawa, Seigo Kanemaru, Junji Itoh
    Abstract:

    An experimental approach to investigate anomalous electrical conduction in a 100 nm width silicon wire by scanning Maxwell-Stress microscopy (SMM) has been reported. The silicon wire exhibited negative resistance and hysteresis characteristics by sweeping the applied voltage up to 50 V. Potential profile along the wire obtained from the SMM images exhibited that lateral electric field significantly increased at the ground-side end of the wire after the hysteresis characteristics emerged. The field increase is interpreted as the conductivity decrease. The origin of the conductance decrease is considered to be generation and trapping of hot holes at the ground-side end.

  • charging damage of silicon on insulator soi wafer determined by scanning Maxwell Stress microscopy
    Japanese Journal of Applied Physics, 2001
    Co-Authors: Takashi Matsukawa, Hiroshi Yokoyama, Hideo Fujii, Seigo Kanemaru, Masayoshi Nagao, Junji Itoh
    Abstract:

    Charging damage of silicon-on-insulator (SOI) wafer induced by electron-beam (EB) lithography and reactive ion etching (RIE) has been investigated in terms of the surface potential change through the processes. Scanning Maxwell-Stress microscopy (SMM) was utilized for measuring the SOI surface potential under a floating condition. Surface contamination due to resist residues was clearly observed in the SMM potential image. Negative charging of the SOI islands induced by EB lithography was observed particularly under an excessive EB exposure condition and conserved for several days. The cause of the negative charging is considered to be the trapping of electrons in the buried oxide of the SOI wafer.

Seigo Kanemaru - One of the best experts on this subject based on the ideXlab platform.

  • work function uniformity of al ni alloys obtained by scanning Maxwell Stress microscopy as an effective tool for evaluating metal transistor gates
    Applied Physics Letters, 2005
    Co-Authors: Takashi Matsukawa, Meishoku Masahara, C Yasumuro, H Yamauchi, E Suzuki, Seigo Kanemaru
    Abstract:

    Work function control of metal transistor gates was implemented with Al–Ni alloys. In addition to obtaining conventional capacitance-voltage (C-V) measurements to evaluate the work function, we microscopically characterized the work function distribution through scanning Maxwell-Stress microscopy (SMM). The C-V curves of the Al–Ni alloys that we investigated exhibited work functions approximately between those of Al and Ni. The SMM analysis revealed that an Al–Ni alloy fabricated by the interdiffusion of a Ni∕Al stack had a significant nonuniformity of the work function. This nonuniformity correlated with degradation of the C-V characteristics for interdiffused Al–Ni alloys.

  • doping diagnosis by evaluation of the surface fermi level using scanning Maxwell Stress microscopy
    Applied Physics Letters, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A microscopic approach for evaluation of the Fermi level on the silicon surface under various doping conditions is reported. We have utilized scanning Maxwell-Stress microscopy (SMM) for measurement of the surface potential. The surface Fermi level evaluated by SMM was almost identical to the bulk Fermi level determined by doping when the surface states are passivated by thermal oxide. The SMM measurement on the pn junction under an electrically shorted condition exhibited contrast in potential which is consistent with that of the bulk Fermi level. The results for the open circuit condition exhibited an inconsistent potential profile, which is due to the photovoltaic effect from light irradiation of the sample.

  • silicon nanowire with programmable conductivity analyzed by scanning Maxwell Stress microscopy
    Journal of Vacuum Science & Technology B, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A novel silicon nanowire with programmable conductivity which utilizes sensitivity of conductance to surface charging has been investigated. The device consists of a nanowire with a width of 10–25 nm and side gates for control of surface charging on to the nanowire. The wire current measured during sweep of the side gate exhibited clear hysteresis characteristics and significant retention of the programmed states for more than 1000 s. Surface potential imaging of the nanowire by means of scanning Maxwell-Stress microscopy (SMM) has been carried out for correlating the programmed conductivity to charging on the nanowire. The SMM images clearly exhibited that charging on the nanowire which provided the programmable conductivity was precisely controlled by the side gate sweep.

  • mechanism of tungsten plug corrosion during chemical stripping process scanning Maxwell Stress microscopy and electrochemical potentiometry studies
    Japanese Journal of Applied Physics, 2002
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Yoko Murata, Takeshi Kotani, Junji Itoh
    Abstract:

    Corrosion of W plugs in LSI interconnects during chemical solvent stripping was investigated by scanning Maxwell-Stress microscopy (SMM). The surface potential of TiN, Al and W, of which the interconnects are composed, was measured by SMM, and the changes in electrostatic charging and work functions through the processes were estimated. After immersion in aqueous amine stripper, which actually caused the W plug corrosion, the work functions of the Al and W films were comparable. Due to the similarity of the work function to the electrochemical reduction potential, we consider that the corrosion protection of the Al/W contact becomes inactive in the aqueous amine stripper. This is also supported by the electrode potential measurement in the aqueous amine stripper, for which the Al potential exhibited a higher value than that of W only for the films after O2 ashing. We consider that the W plug corrosion is caused by the electrochemical interaction between the aqueous amine stripper and the material deposited on the Al by O2 ashing.

  • characterization of electrical conduction in silicon nanowire by scanning Maxwell Stress microscopy
    Applied Physics Letters, 2001
    Co-Authors: Hideo Fujii, Hiroshi Yokoyama, Takashi Matsukawa, Seigo Kanemaru, Junji Itoh
    Abstract:

    An experimental approach to investigate anomalous electrical conduction in a 100 nm width silicon wire by scanning Maxwell-Stress microscopy (SMM) has been reported. The silicon wire exhibited negative resistance and hysteresis characteristics by sweeping the applied voltage up to 50 V. Potential profile along the wire obtained from the SMM images exhibited that lateral electric field significantly increased at the ground-side end of the wire after the hysteresis characteristics emerged. The field increase is interpreted as the conductivity decrease. The origin of the conductance decrease is considered to be generation and trapping of hot holes at the ground-side end.

Takashi Matsukawa - One of the best experts on this subject based on the ideXlab platform.

  • work function uniformity of al ni alloys obtained by scanning Maxwell Stress microscopy as an effective tool for evaluating metal transistor gates
    Applied Physics Letters, 2005
    Co-Authors: Takashi Matsukawa, Meishoku Masahara, C Yasumuro, H Yamauchi, E Suzuki, Seigo Kanemaru
    Abstract:

    Work function control of metal transistor gates was implemented with Al–Ni alloys. In addition to obtaining conventional capacitance-voltage (C-V) measurements to evaluate the work function, we microscopically characterized the work function distribution through scanning Maxwell-Stress microscopy (SMM). The C-V curves of the Al–Ni alloys that we investigated exhibited work functions approximately between those of Al and Ni. The SMM analysis revealed that an Al–Ni alloy fabricated by the interdiffusion of a Ni∕Al stack had a significant nonuniformity of the work function. This nonuniformity correlated with degradation of the C-V characteristics for interdiffused Al–Ni alloys.

  • doping diagnosis by evaluation of the surface fermi level using scanning Maxwell Stress microscopy
    Applied Physics Letters, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A microscopic approach for evaluation of the Fermi level on the silicon surface under various doping conditions is reported. We have utilized scanning Maxwell-Stress microscopy (SMM) for measurement of the surface potential. The surface Fermi level evaluated by SMM was almost identical to the bulk Fermi level determined by doping when the surface states are passivated by thermal oxide. The SMM measurement on the pn junction under an electrically shorted condition exhibited contrast in potential which is consistent with that of the bulk Fermi level. The results for the open circuit condition exhibited an inconsistent potential profile, which is due to the photovoltaic effect from light irradiation of the sample.

  • silicon nanowire with programmable conductivity analyzed by scanning Maxwell Stress microscopy
    Journal of Vacuum Science & Technology B, 2003
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Meishoku Masahara, Masayoshi Nagao, Hisao Tanoue, Junji Itoh
    Abstract:

    A novel silicon nanowire with programmable conductivity which utilizes sensitivity of conductance to surface charging has been investigated. The device consists of a nanowire with a width of 10–25 nm and side gates for control of surface charging on to the nanowire. The wire current measured during sweep of the side gate exhibited clear hysteresis characteristics and significant retention of the programmed states for more than 1000 s. Surface potential imaging of the nanowire by means of scanning Maxwell-Stress microscopy (SMM) has been carried out for correlating the programmed conductivity to charging on the nanowire. The SMM images clearly exhibited that charging on the nanowire which provided the programmable conductivity was precisely controlled by the side gate sweep.

  • mechanism of tungsten plug corrosion during chemical stripping process scanning Maxwell Stress microscopy and electrochemical potentiometry studies
    Japanese Journal of Applied Physics, 2002
    Co-Authors: Takashi Matsukawa, Seigo Kanemaru, Yoko Murata, Takeshi Kotani, Junji Itoh
    Abstract:

    Corrosion of W plugs in LSI interconnects during chemical solvent stripping was investigated by scanning Maxwell-Stress microscopy (SMM). The surface potential of TiN, Al and W, of which the interconnects are composed, was measured by SMM, and the changes in electrostatic charging and work functions through the processes were estimated. After immersion in aqueous amine stripper, which actually caused the W plug corrosion, the work functions of the Al and W films were comparable. Due to the similarity of the work function to the electrochemical reduction potential, we consider that the corrosion protection of the Al/W contact becomes inactive in the aqueous amine stripper. This is also supported by the electrode potential measurement in the aqueous amine stripper, for which the Al potential exhibited a higher value than that of W only for the films after O2 ashing. We consider that the W plug corrosion is caused by the electrochemical interaction between the aqueous amine stripper and the material deposited on the Al by O2 ashing.

  • characterization of electrical conduction in silicon nanowire by scanning Maxwell Stress microscopy
    Applied Physics Letters, 2001
    Co-Authors: Hideo Fujii, Hiroshi Yokoyama, Takashi Matsukawa, Seigo Kanemaru, Junji Itoh
    Abstract:

    An experimental approach to investigate anomalous electrical conduction in a 100 nm width silicon wire by scanning Maxwell-Stress microscopy (SMM) has been reported. The silicon wire exhibited negative resistance and hysteresis characteristics by sweeping the applied voltage up to 50 V. Potential profile along the wire obtained from the SMM images exhibited that lateral electric field significantly increased at the ground-side end of the wire after the hysteresis characteristics emerged. The field increase is interpreted as the conductivity decrease. The origin of the conductance decrease is considered to be generation and trapping of hot holes at the ground-side end.