Interface charge engineering for manipulation of band alignment at dielectric interfaces and demonstration of its impact on device characteristics

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H04550
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Kita Koji 東京大学, 大学院新領域創成科学研究科, 教授 (00343145)
• Project Period (FY): 2021-04-05 – 2024-03-31
• Keywords: 電子・電気材料 / 表面・界面物性 / 誘電体 / 電子デバイス・機器 / 界面双極子 / 応力印加

Outline of Final Research Achievements

The SiC/SiO2 and Ga2O3/SiO2 interfaces, which are important for the gate stack structure of next-generation power MOFETs, are subject to the formation of interfacial dipoles and the generation / dissipation of interfacial fixed charges,even though actual interface phenomenon with these processes have not been clarified.In this study, we not only show for the first time the contribution of each factor quantitatively to the change in band alignment and flatband voltage, but also discover that these changes can sometimes become very sensitive to a small amount of strain applied to the device. In the analysis of the interfacial dipole effect in epitaxial stacks of perovskite oxides, we proved the validity of the understanding taht the inteface dipoles are generated locally and their magnitudes are distributed laterally in the plane.

Free Research Field

電子デバイス材料工学

Academic Significance and Societal Importance of the Research Achievements

ワイドギャップ半導体のMOSFETでは閾値の制御性や，ゲートリーク電流の抑制が重要な課題となっている。これらの特性はMOS界面のバンドアライメントを決定する界面ダイポール効果や，フラットバンド電圧を左右する固定電荷によって決定されており，本研究ではそれらを明確に区別する手順を示すとともに，実際に各因子を定量化し，それらの制御のための指針を提案した。さらに応力がこれらに影響を与える理由も明らかにした。これらの情報は，デバイス構造の設計やデバイス形成プロセスの設計において重要な知見となる。