Single crystal growth of transparent oxide semiconductor and analysis of its intrinsic physical properties

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K05306
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29010:Applied physical properties-related
• Research Institution: Tokyo University of Science
• Principal Investigator: Kase Naoki 東京理科大学, 理学部第一部応用物理学科, 嘱託特別講師 (10613630)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 単結晶 / 半導体 / 透明酸化物 / 透明酸化物半導体 / IZO / IGZO

Outline of Final Research Achievements

We have developed In-Ga-Zn-O bulk single crystals using the Floating Zone method, which had not been reported before. We successfully grew large single crystals not only for InGaO3(Zn)n with n = 1, but also for n = 2 and 3. Furthermore, we have successfully grown large single crystals of so-called IZO-13 that do not contain Ga. Additionally, we succeeded in growing large single crystals with Sn substitution, aiming for improved mobility. Using these grown single crystals, various physical property measurements were conducted, revealing that the conductivity along the c-axis deteriorates as n increases, particularly due to electrical conductivity anisotropy.

Free Research Field

Semiconductor

Academic Significance and Societal Importance of the Research Achievements

これまで応用研究が盛んなIn-Ga-Zn-Oにおいてこれまで育成が困難であった大型単結晶の育成に成功した。この成果によってこれまで未解明であったバルク結晶を用いた基礎物性が明らかにできた。特に電気伝異方性については単結晶を用いなければ不可能な実験であるため、本研究によってIGZOの電気伝導現象の理解を大きく深めることができた。