東京大学 · 工学
Yongsheng Ren教授の研究室では、高エントロピー合金や高性能アルミニウム合金の開発に加え、単結晶シリコンにおける不純物制御やレアメタルを用いた不純物除去技術の研究が進められています。特に、ジルコニウムを用いたボロン除去法や、Si-Cu系溶融状態を用いた高純度シリコンの精製技術に注力しており、半導体材料の高効率化に貢献する革新的なプロセス開発が特徴です。また、Czochralski法を用いた大径シリコン単結晶の成長条件最適化や、酸素不純物の低減に向けた加熱部構造の改善も行っています。
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In recent years, high-entropy alloys (HEAs) have attracted tremendous attention in various fields. With multiple-principal elements and multiple core effects, giving them different organizational structures and unique properties compared with conventional alloys, providing unlimited development potential and bringing promising potential applications for HEAs. After almost 30 years of development, the preparation and research methods of HEAs have greatly expanded, the systems have been optimized,
Aluminum, the most produced non-ferrous metal in the world, is highly regarded for its light weight, high specific strength, and excellent thermal conductivity. With the continuous development of aerospace, precision electronics, photovoltaic semiconductors and other emerging strategic industries, the demand for high-performance aluminum alloys is also booming. The paper discusses recent advances in aluminum alloy melt purification, focusing on the development of conventional purification treatm
Aluminum is the world's largest production of non-ferrous metals, with light weight, high specific strength, excellent electrical and thermal conductivity and other characteristics. With the continuous development of aerospace, precision electronic instruments, photovoltaic semiconductors and other emerging strategic industries, the demand for high-performance materials of aluminum alloys has become increasingly strong. This paper reviews the research progress of aluminum alloy melt refinement t
A novel approach was put forward to remove B from Si by utilizing Zr as an additive during solidification, whereby, using the Si–Cu solvent, bulk Si with large area and low boron content was obtained. The premise of this work is based on the following parameters: (i) the lower liquidus temperature of the Si–Cu system; (ii) the notable density difference between solid Si and liquid Si–Cu; (iii) the low solubility of Cu in solid Si; and (iv) the strong affinity of Zr for B, enhancing boride format
Based on (i) the low liquidus temperature of Si–Cu systems, (ii) low solubility of Cu in solid Si, and (iii) a strong affinity of Zr to B for the enhanced boride formation, a novel method to remove B from Si using Zr as a trapping agent via a Si–Cu solvent was developed in this study. B-bearing polygonal ZrBx precipitations found at the bottom of test samples were confirmed as ZrB2 by electron probe microanalysis. Thermodynamic analysis revealed that the solubility products of ZrB2 in a Si–Cu me
• Heater radiant area affects crystal oxygen concentration and heater power . • Quartz crucible temperature controls crystal oxygen concentration. • Reducing heater height lowers crystal oxygen but raises power. • With the upgraded heater, power decreased by 1.07 kW and average head oxygen concentration decreased by 0.66 ppma. Oxygen is the major impurity in single-crystal silicon rod derived from the growth of large-diameter n-type Czochralski (Cz) silicon, which could exert severe affects on t
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