Dr. Susumu Kato Profile

Dr. Susumu Kato

at AIST

SPIE Involvement:

Author

Publications (8)

Proceedings Article | 2 March 2020 Paper

Bead-on-plate welding of pure copper sheet with 200 W high intensity blue diode laser

K. Morimoto, M. Tsukamoto, Y. Sato, S. Masuno, S. Kato, K. Azumi, Y. Hayashi, N. Abe

Proceedings Volume 11273, 112730E (2020) https://doi.org/10.1117/12.2545432

KEYWORDS: Laser welding, Copper, Semiconductor lasers, Absorption, Video, Cameras, Laser cutting, High speed cameras, Laser irradiation, Lithium

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Proceedings Article | 13 November 2017 Paper

Kinetic model of optical damage in transparent crystals under continuous-wave laser irradiation

Susumu Kato, Atsushi Sunahara, Sunao Kurimura

Proceedings Volume 10447, 104471Z (2017) https://doi.org/10.1117/12.2279957

KEYWORDS: Absorption, Polarons, Crystals, Continuous wave operation, Color centers, Optical damage, Excitons

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Proceedings Article | 23 April 2001 Paper

Anomalous absorption of linearly polarized laser pulse in overdense plasma

Tatsufumi Nakamura, Susumu Kato, Toshikazu Kato

Proceedings Volume 4424, (2001) https://doi.org/10.1117/12.425614

KEYWORDS: Absorption, Pulsed laser operation, Plasma, Diffusion, Skin, Magnetism, Anisotropy, Electromagnetism, Laser applications, Ions

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Proceedings Article | 23 April 2001 Paper

Numerical simulation of shockwave by KrF laser ablation

Susumu Kato, Kaori Kato, Takayuki Aoki, Ryuichi Ishizaki, Osamu Tatebe, Isao Matsushima, Eiichi Takahashi, Yoshiro Owadano

Proceedings Volume 4424, (2001) https://doi.org/10.1117/12.425608

KEYWORDS: Laser ablation, Optical simulations, Computer simulations, Numerical simulations, Laser irradiation, Plasma, Chlorine, Laser development, Fluid dynamics, Solids

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Proceedings Article | 23 April 2001 Paper

High-intensity pulse generation by saturated amplification of Stokes pulse with steep leading edge

Kenji Kuwahara, Eiichi Takahashi, Yuji Matsumoto, Isao Matsushima, Isao Okuda, Susumu Kato, Yoshiro Owadano

Proceedings Volume 4424, (2001) https://doi.org/10.1117/12.425582

KEYWORDS: Pulsed laser operation, Oscillators, Liquids, Laser amplifiers, Laser scattering, Scattering, Oscilloscopes, Laser damage threshold, Phonons, Reflectivity

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Proceedings Article | 3 April 2000 Paper

Pulse shaping of KrF laser by stimulated Brillouin scattering

Kenji Kuwahara, Eiichi Takahashi, Yuji Matsumoto, Susumu Kato, Yoshiro Owadano

Proceedings Volume 3889, (2000) https://doi.org/10.1117/12.380859

KEYWORDS: Pulsed laser operation, Liquids, Laser scattering, Scattering, Laser amplifiers, Pulse shaping, Absorption, Fabry–Perot interferometers, Oscilloscopes, Lithium

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Proceedings Article | 11 January 2000 Paper

Electron-beam-pumped high-repetition-rate KrF laser system

Eiichi Takahashi, Isao Okuda, Yuji Matsumoto, Isao Matsushima, Susumu Kato, Kenji Kuwahara, Yoshiro Owadano

Proceedings Volume 3886, (2000) https://doi.org/10.1117/12.375130

KEYWORDS: Prototyping, Titanium, Switches, Gas lasers, Molybdenum, Fusion energy, Magnetism, Pulsed laser operation, Transmittance, Laser systems engineering

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Proceedings Article | 1 May 1990 Paper

Gate oxide breakdown by focused ion-beam irradiation

Yuichi Nakashima, Hiroaki Morimoto, Hirohisa Yamamoto, Susumu Kato, Yaichiro Watakabe, Akihiko Yasuoka

Proceedings Volume 1263, (1990) https://doi.org/10.1117/12.20145

KEYWORDS: Oxides, Ion beams, X-ray technology, Molybdenum, Electrodes, Dielectric breakdown, Gallium, Ions, Silicon, X-ray lithography

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Dielectric breakdown of gate oxide by the focused iou beam (FIB) irradiation of the MOS structure has been studied. The sample device structure was that of an MOS transistor about to be ion-implanted in the source and drain (S/D) regions. The gate poly-silicon electrode was extended to the pad electrode on the thick field oxide. The thicknesses of the gate and field oxide layers were 25 iim and 500 mu, respectively. That of the poly-silicon layer was 250 nm. The typical areas of the gate and the pad electrodes were 31-100 jzm2 aiid 2-4x iO pm2, respectively. Gallium FIB, accelerated by 40 keV, was irradiated to sample devices. The total dose until the breakdowii depends on the irradiated location of the device. In the case that the edge of the polysilicon layer adjacent to the S/D regions is irradiated, the dose is the least. If the gate oxide layer has not been removed on the S/D regions, the dose exceeds that for the sample with the gate oxide layer etched there, although not greater than that in the case that any other part of the poly-silicon layer is irradiated. The electroluminescence measurement of some samples indicates that such edge irradiation iiiduces damages at a spot on the irradiated edge of the gate oxide. Such damages are probably due to the combiiiation of conductive microbridge formation and the electrical dielectric breakdown around the bridge. The microbridge is formed by the implantation of gallium ions, and/or adhesion of gallium and silicon atonis at the sidewall of the gate oxide. In the experiments where an area around the center of the polysilicon pad electrode was irradiated, two breakdown modes were observed: breakdown due to gate-culTent stress and instant breakdown. The gate potential during the FIB irradiation was obtained from the measured secondary electron current. The potential is approximately equal to that measured during the conventional constant-current-stress (005) lifetime experiment. This proves that gate oxide is stressed by current during irradiation. The time to breakdown becomes shorter with decrease in the gate area if the FIB current is the same. The smaller the devise becomes, the 005-like mode will be the more serious. Instant breakdown mode appears when the beam current is high. Detailed analysis reveals discrepancies between the phenomena and simple conjectures based on the 005 lifetime. By the irradiation, some samples are broken in far shorter time than expected from the 005 lifetime measurement, whereas the rest of the samples survive longer than the expectation. This suggests that there is a stronger stress at the onset of the irradiation. This breakdown mode is, at least at present, uncontrollable and most hazardous, to be overcome for improved

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