Single crystal growth of mixed semicoductor alloys using "predominant growth plane" at solid-liquid interface

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15070
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 26060:Metals production and resources production-related
• Research Institution: National Institute of Advanced Industrial Science and Technology (2021-2022); Tohoku University (2020)
• Principal Investigator: Shiga Keiji 国立研究開発法人産業技術総合研究所, 材料・化学領域, 研究員 (30803150)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 結晶成長 / 凝固 / 双晶 / その場観察

Outline of Final Research Achievements

This study aimed to establish guidelines for growing high-quality mixed crystals (uniform crystals formed by the mixture of more than two atoms) by understanding how semiconductor materials grow, including how their grains increase in size and how defects form. Through direct observations of the boundary between the solid and liquid phases during the solidification of Sb-Bi mixed alloys, the processes of morphological transformation and the formation of flat faces, known as facets, were elucidated. Similar observations were performed during the solidification of InSb-GaSb mixed alloys and Al-Si alloys. It was found that the formation of facets causes the formation of twin boundaries at specific sites between grains and leads to the anisotropic growth of special crystal structures called eutectics.

Free Research Field

結晶成長

Academic Significance and Societal Importance of the Research Achievements

金属と比較して、半導体は凝固時に固体と液体の界面に特異な面（ファセット）が発達するため、半導体結晶の成長は異方的である。本研究では、固液界面のその場観察により、ファセットの形成が結晶粒の成長の挙動と欠陥の形成に著しい影響を及ぼすことを実験的に明らかにした。また、熱拡散方程式と欠陥形成に伴う自由エネルギーの計算により、固液界面の形状の不安定化と双晶粒界の形成に必要な駆動力の定量解析を行った。半導体材料の固液界面における結晶成長の様相を実験的・理論的に明らかにした点は、結晶成長の学理の構築に資するものであり、半導体結晶や混晶材料の高品質なバルク結晶の育成に重要な知見を与えると期待される。