2019 Fiscal Year Final Research Report
High-speed in situ X-ray diffraction for dislocation control in semiconductor crystal growth
| Project/Area Number |
17H02778
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Crystal engineering
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| Research Institution | National Institutes for Quantum and Radiological Science and Technology |
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Principal Investigator |
Takahasi Masamitu 国立研究開発法人量子科学技術研究開発機構, 次世代放射光施設整備開発センター, 上席研究員(定常) (00354986)
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| Co-Investigator(Kenkyū-buntansha) |
Voegeli Wolfgang 東京学芸大学, 教育学部, 准教授 (90624924)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | その場X線回折 / 分子線エピタキシー / III-V族半導体 / 窒化物半導体 |
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| Outline of Final Research Achievements |
In situ X-ray reciprocal space mapping at a time scale of milliseconds has been achieved using X-ray optics generating monochromatic X-rays with an angular divergence of ~3 degrees. This X-ray optical setup consisting of three optical components was designed for a molecular-beam epitaxy chamber integrated with a multi-axis X-ray diffractometer installed on the synchrotron beamline BL11XU at SPring-8. The scattered X-rays were measured with a two-dimensional X-ray detector so that intensity distributions in a wide range of reciprocal space could be recorded in a single shot image. This high-speed X-ray diffraction technique was applied to the study of the molecular beam epitaxial growth of III-V semiconductors including InGaAs/GaAs(001) and InGaN/GaN(0001). The relaxation process of the strained heteroepitaxial films was revealed with a time resolution of 100 msec.
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| Free Research Field |
結晶工学
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| Academic Significance and Societal Importance of the Research Achievements |
原子・分子レベルの素過程からマクロな秩序構造が形成される結晶成長は、本質的にマルチスケールな現象である。10桁以上の時間スケールにまたがる一連の過程の中で、ミリ秒スケールの現象は、結晶品質を決定づける最大の要素である転位発生・増殖に対応し、きわめて重要でありながら、直接観測が未だ及んでいない領域であった。本研究で開発された多角度同時分散光学系を用いたミリ秒スケールのX線回折測定によって、転位の起源や、貫通転位発生に先立つ前兆現象の有無、組成分離と格子緩和の因果関係などが明らかになり、転位の制御、ひいては単結晶薄膜の結晶性向上に向けた知見が得られた。
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