Updated on 2026/09/12

写真a

 
USUDA KOJI
 
Organization
Organization Organization for the Strategic Coordination of Research and Intellectual Properties Professor (non-tenured)
Title
Professor (non-tenured)
External link

Papers

  • Surface-pyramid-induced strain relaxation in (110)-oriented SiGe thin films revealed by Micro-Raman spectroscopy Reviewed

    Yuta Ito, Koji Usuda, Kiu Inami, Naoto Kumagai, Toshifumi Irisawa, Atsushi Ogura

    MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING   209   2026.7

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.mssp.2026.110581

    Web of Science

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  • Evaluation of bias-dependent band structure changes in metal–oxide–semiconductor structures with varying doping concentrations using laboratory hard x-ray photoelectron spectroscopy Reviewed

    Takuya Minowa, Koji Usuda, Ryo Yokogawa, Atsushi Ogura

    Applied Physics Letters   126 ( 7 )   2025.2

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    Publishing type：Research paper (scientific journal)   Publisher：AIP Publishing  

    Direct observation of the band structure variation of electrical devices, such as MOSFETs, during device operation is the most important for understanding MOSFET device operation. However, there are a few reports on the direct measurement of variation in the metal–oxide–semiconductor (MOS) interface band structure during operation, and further investigation is required. This paper focuses on elucidating the changes in the band structure at buried interfaces under applied bias using a nondestructive approach. We conducted measurements using bias-applied laboratory hard x-ray photoelectron spectroscopy (Lab. HAXPES) with liquid gallium (Ga) x-ray source on MOS structures, which are widely recognized as fundamental and commonly used devices. We utilize HAXPES with Ga x-ray, providing high-energy/intensity x-rays, to achieve sufficient detection depth and enable observation of the deeper regions of the silicon substrate buried under gold and silicon dioxide layers. As a result, this approach allowed us to observe bias-dependent peak shifts resulting from changes in the band structure in detail. We observe HAXPES peak shift caused by the different substrate concentrations. Additionally, we obtained detailed information on band bending by applying a wider range of bias compared to previous bias applied HAXPES.

    DOI： 10.1063/5.0245254

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  • Phonon dispersion of bulk Ge-rich SiGe: inelastic X-ray scattering studies Reviewed

    Koji Usuda, Yuya Oyanagi, Ryo Yokogawa, Hiroshi Uchiyama, Satoshi Tsutsui, Ichiro Yonenaga, Atsushi Ogura

    Japanese Journal of Applied Physics   59 ( 6 )   061003-1 - 061003-6   2020.6

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP Publishing  

    DOI： 10.35848/1347-4065/ab8e07

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  • Determination of phonon deformation potentials and strain-shift coefficients in Ge-rich Si1-xGex using bulk Ge-rich Si1-xGex crystals and oil-immersion Raman spectroscopy Reviewed

    Ryo Yokogawa, Kazuma Takeuchi, Tatsumi Murakami, Koji Usuda, Ichiro Yonenaga, Atsushi Ogura

    Japanese Journal of Applied Physics   57 ( 10 )   106601-1 - 106601-6   2018.10

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.7567/JJAP.57.106601

    Web of Science

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  • Evaluation of Anisotropic Biaxial Stress in Thin Strained-SiGe Layer Using Surface Enhanced Raman Spectroscopy Reviewed

    Shotaro Yamamoto, Daisuke Kosemura, S.Norhidayah C.M.Yusoff, Takahiro Kijima, Ryosuke Imai, Kazuma Takeuchi, Ryo Yokogawa, Koji Usuda, Atsushi Ogura

    ECS Transactions   64 ( 6 )   841 - 847   2014.10

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    Language：English   Publishing type：Research paper (international conference proceedings)  

    DOI： 10.1149/06406.0841ecst

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MISC

  • CVD-SiGe/Si(110)構造における SiGe 層の臨界膜厚のGe濃度依存性

    臼田宏治, 伊波希宇, 熊谷直人, 熊谷直人, 入沢寿史, 小椋厚志

    応用物理学会春季学術講演会講演予稿集(CD-ROM) 73th 2026年   2025.3

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    Authorship：Lead author   Language：Japanese   Publishing type：Meeting report  

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  • Anisotropy Analysis of SiGe Thin Film Grown on Si (110) Off-Angle Substrates by Chemical Vapor Deposition

    伊波希宇, 伊波希宇, 臼田宏治, 熊谷直人, 熊谷直人, 入沢寿史, 入沢寿史, 小椋厚志, 小椋厚志

    応用物理学会学術講演会講演予稿集(CD-ROM)   86th   2025

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  • Strain Evaluation of Surface Roughness Effect in SiGe Epi. Thin Films on (110)Si Sub. by Raman Spectroscopy

    伊藤佑太, 伊藤佑太, 伊波希宇, 伊波希宇, 臼田宏冶, 小椋厚志, 小椋厚志

    応用物理学会学術講演会講演予稿集(CD-ROM)   86th   2025

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  • Examination of Method for Evaluating Critical Thickness of SiGe/Si(110) Structures

    臼田宏治, 伊波希宇, 伊波希宇, 熊谷直人, 熊谷直人, 入沢寿史, 入沢寿史, 小椋厚志, 小椋厚志

    応用物理学会学術講演会講演予稿集(CD-ROM)   86th   2025

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    Authorship：Lead author  

    J-GLOBAL

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