Updated on 2023/09/12

写真a

 
SHIKANO Haruka
 
Organization
Institute of Materials and Systems for Sustainability Designated lecturer
Title
Designated lecturer
 

Papers 6

  1. Investigation on Applying an InGaN Photocathode with Negative Electron Affinity for Electric Propulsion

    INOUE Yusuke, NISHITANI Tomohiro, HONDA Anna, SATO Daiki, SHIKANO Haruka, KOIZUMI Atsushi, HONDA Yoshio, ICHIHARA Daisuke, SASOH Akihiro

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES   Vol. 66 ( 1 ) page: 10 - 13   2023

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    Language:English   Publisher:THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES  

    DOI: 10.2322/tjsass.66.10

    Web of Science

    Scopus

    CiNii Research

  2. Photoelectron beam technology for SEM imaging with pixel-specific control of irradiation beam current

    Nishitani T., Arakawa Y., Noda S., Koizumi A., Sato D., Shikano H., Iijima H., Honda Y., Amano H.

    METROLOGY, INSPECTION, AND PROCESS CONTROL XXXVII   Vol. 12496   2023

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    Publisher:Proceedings of SPIE - The International Society for Optical Engineering  

    The scanning electron microscope (SEM) with photocathode technology was launched by retrofitting the photocathode electron gun to a commercial-based SEM system. In this SEM system, the excitation laser for photoelectron generation from the photocathode is synchronized to the scanning signal. SEM images were obtained by high-speed modulation of the photoelectron beam current using the photocathode SEM, where the location in the field of view and its irradiation current were arbitrarily selected on a pixel-by-pixel basis (Selective e-Beaming technology). As a demonstration experiment contributing to non-contact electrical inspection, low-voltage SEM imaging of MOS-FET structures in 3D-NAND flash memory was performed using this selective e-beam technology. As a result, changes in the voltage contrast of the drain electrode were observed in response to on/off selective electron beam irradiation to the gate electrode in the MOS-FET structure. As an extension of the selective electron beaming technology, a Yield Controlled e-beaming (YCeB) technology was invented to control the secondary electron yield generated in the entire field of view of the SEM image by feedback control of the laser power irradiating the photocathode to the intensity of each pixel in the SEM image. The YCeB image, in which the laser power intensity corresponding to the probe intensity is modulated so that the secondary electron yield generated in the entire field of view of the SEM image is constant, is a clearer image with less noise than the original SEM image.

    DOI: 10.1117/12.2657853

    Web of Science

    Scopus

  3. Novel Electron Beam Technology using InGaN Photocathode for High-Throughput Scanning Electron Microscope Imaging

    Sato Daiki, Koizumi Atsushi, Shikano Haruka, Noda Shotaro, Otsuka Yohei, Yasufuku Daisuke, Mori Kazumasa, Iijima Hokuto, Nishitani Tomohiro, Honda Yoshio, Amano Hiroshi

    METROLOGY, INSPECTION, AND PROCESS CONTROL XXXVII   Vol. 12496   2023

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    Publisher:Proceedings of SPIE - The International Society for Optical Engineering  

    An InGaN photocathode with a negative electron affinity (NEA) surface is suitable for industrial use because of features such as a long quantum efficiency lifetime, availability with a visible laser as an excitation light source, and the presence of a transmission-type structure. The first objective is the development of an InGaN photocathode electron gun that can be mounted on a scanning electron microscope (SEM) and the evaluation of the electron beam size at the emission point, maximum emission current, and transverse energy of the electron beam, which are important factors for realizing a high probe current in the SEM. The second objective is the evaluation of emission current stability, while the third objective is the generation of a pulsed electron beam and multi-electron beam from the InGaN photocathode. The parameters of the electron beam from the photocathode electron gun were an emission beam radius of 1 µm, transverse energy of 44 meV, and an emission current of up to 110 µA. Using a high beam current with low transverse energy from the photocathode, a 13 nA probe current with 10 nm SEM resolution was observed with 15 µA emission. At 15 µA, the continuous electron beam emission for 1300 h was confirmed; at 30 µA, the cycle time between the NEA surface reactivations was confirmed to be 90 h with 0.043% stability. Moreover, a 4.4 ns pulsed e-beam with a 4.7 mA beam current was generated, and a 5 × 5 multielectron beam with 12% uniformity was then obtained. The advantages of the InGaN photocathode, such as high electron beam current, low transverse energy, long quantum efficiency lifetime, pulsed electron beam, and multi-electron beam, are useful in industries including semiconductor device inspection tools.

    DOI: 10.1117/12.2657032

    Web of Science

    Scopus

  4. Scanning electron microscope imaging by selective e-beaming using photoelectron beams from semiconductor photocathodes

    Nishitani Tomohiro, Arakawa Yuta, Noda Shotaro, Koizumi Atsushi, Sato Daiki, Shikano Haruka, Iijima Hokuto, Honda Yoshio, Amano Hiroshi

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   Vol. 40 ( 6 )   2022.12

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    Publisher:Journal of Vacuum Science and Technology B  

    Pulsed electron beams from a photocathode using an InGaN semiconductor have brought selectively scanning technology to scanning electron microscopes, where the electron beam irradiation intensity and area can be arbitrarily selected within the field of view in SEM images. The p-type InGaN semiconductor crystals grown in the metalorganic chemical vapor deposition equipment were used as the photocathode material for the electron beam source after the surface was activated to a negative electron affinity state in the electron gun under ultrahigh vacuum. The InGaN semiconductor photocathode produced a pulsed electron beam with a rise and fall time of 3 ns, consistent with the time structure of the irradiated pulsed laser used for the optical excitation of electrons. The InGaN photocathode-based electron gun achieved a total beam operation time of 1300 h at 15 μA beam current with a downtime rate of 4% and a current stability of 0.033% after 23 cycles of surface activation and continuous beam operation. The InGaN photocathode-based electron gun has been installed in the conventional scanning electron microscope by replacing the original field emission gun. SEM imaging was performed by selective electron beaming, in which the scanning signal of the SEM system was synchronized with the laser for photocathode excitation to irradiate arbitrary regions in the SEM image at arbitrary intensity. The accuracy of the selection of regions in the SEM image by the selective electron beam was pixel by pixel at the TV scan speed (80 ns/pix, 25 frame/s) of the SEM.

    DOI: 10.1116/6.0002111

    Web of Science

    Scopus

  5. Time response measurement of pulsed electron beam from InGaN photocathode

    Sato, D., Shikano, H., Koizumi, A., Nishitani, T.

      Vol. 40   page: 064204   2022.11

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  6. Dependence of electron emission current density on excitation power density from Cs/O-activated negative electron affinity InGaN photocathode

    Koizumi, A., Sato, D., Shikano, H., Iijima, H., Nishitani, T.

    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B   Vol. 40   page: 062202   2022.10

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