2022 Fiscal Year Final Research Report
Study of slow trap characteristics and reduction methods of its density in Ge MOS interfaces for future devices.
| Project/Area Number |
20K14779
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 21050:Electric and electronic materials-related
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| Research Institution | Chiba University (2021-2022)
Tokyo University of Science (2020) |
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Principal Investigator |
Ke Mengnan 千葉大学, 大学院工学研究院, 助教 (40849402)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | MOS界面 / ゲルマニウム / MOSFET / 遅い準位 / 界面準位 |
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| Outline of Final Research Achievements |
(1)We have evaluated the densities of existing, generated electron slow trap and hole trap density for Al2O3/Y2O3/GeOx/n-Ge MOS interfaces with post-PO and Al2O3/GeOx/n-Ge MOS interfaces with post- and pre-PO. The pre-PO and Y2O3 insertion have been found to reduce existing and generated slow electron traps, respectively, contributing to the reduction in total slow trap density.
(2)We have discriminated the different types of slow traps in Ge nMOS interfaces in large Eox. It was found that only existing slow traps are responsible in low Eox, while generation of slow traps and hole trapping additionally occur in high Eox.
(3)A new measurement procedure to discriminate hole and electron slow traps has been proposed and applied to Al2O3/GeOx/p-Ge gate stacks. Both electron and hole slow trap densities have been successfully evaluated in p-Ge MOS capacitors The electron slow traps, evident under the strong inversion condition, is very important in understanding the Nst-Eox relationship.
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| Free Research Field |
電気電子材料工学
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| Academic Significance and Societal Importance of the Research Achievements |
近年Si CMOS微細化による種々の物理的限界の顕在化が問題となっており、Siよりも移動度の高い半導体を利用して電流駆動力を向上させるMOSトランジスタ技術に注目が集まっている。Geは、高い電子移動度と正孔移動度をもち、かつSiプラットフォームとも比較的親和性が高いことから、未来のチャネル材料の最優先候補として考えられている。本研究は、Geを用いた高性能のトランジスタ実現のために必須の高品質Ge MOS構造の形成技術の提案と物理的機構の解明について研究を進めてきた。特に、Geトランジスタの閾値変動の起源と考えられている界面近傍の遅い準位の物理的機構の解明とその密度の低減手法の提案した。
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