Understanding the Origin of Dipole Layer Formation at Interfaces between Two Dielectric Materials

了解两种介电材料之间界面处偶极子层形成的起源

• 批准号: 17J10451
• 负责人: 費 嘉陽
• 金额: $ 1.09万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2017
• 资助国家: 日本
• 起止时间: 2017-04-26 至 2019-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17J10451/
• 关键词: dielectric interfaces; dipole layer; flatband voltage shift

The purpose of this study is to understand the origin of dipole layer formation at gate dielectric interfaces which shifts the threshold voltage of advanced MOSFETs. Therefore two dielectric interfaces, Al2O3/AlFxOy and MgO/Al2O3, were studied.Dipole layer formation at AlFxOy/Al2O3 and MgO/Al2O3 interfaces was studied by both experiments and classic Molecular Dynamics simulation. Positive dipole layer formation was observed for AlFxOy/Al2O3 while negative for MgO/Al2O3. The simulation has suggested oxygen migration playing an important role on charge separation at AlFxOy/Al2O3 and Mg cations migration playing an important role at MgO/Al2O3. Different roles of ionic motion at these two interfaces are considered to be the result of the properties of the interfaces. The ionic motions are mainly determined by stress relaxation at AlFxOy/Al2O3 while formation of chemically stable compound determines the ionic motions at MgO/Al2O3. The results indicate a combined effects of cation and anion motion during the dielectric interface formation to caused charge separation at dielectric interfaces.The study on dipole layer formation at various dielectric interfaces provides us with an insight in understanding the relationship between the dipole layer formation at dielectric interfaces and interface ionic motions

本研究的目的是了解偶极层形成在栅极介电界面的偏移先进的MOSFET的阈值电压的起源。因此，我们研究了Al_2O_3/AlF_xO_y和MgO/Al_2O_3两种介电界面，并通过实验和经典的分子动力学模拟研究了AlF_xO_y/Al_2O_3和MgO/Al_2O_3界面上偶极层的形成。正偶极子层的形成观察AlFxOy/Al 2 O3，而负MgO/Al 2 O3。模拟表明，氧迁移对AlFxOy/Al 2 O3的电荷分离起着重要作用，而镁阳离子迁移在MgO/Al 2 O3中起着重要作用。离子运动在这两个界面上的不同作用被认为是界面性质的结果。AlFxOy/Al 2 O3处的离子运动主要由应力松弛决定，而MgO/Al 2 O3处的离子运动则由化学稳定化合物的形成决定。结果表明，电介质界面形成过程中阳离子和阴离子运动的共同作用导致了电介质界面上的电荷分离，对不同电介质界面上偶极层形成的研究为理解电介质界面上偶极层形成与界面离子运动之间的关系提供了新的思路

项目成果

Opportunity of dipole layer formation at non-SiO2 dielectric interfaces in two cases: multi-cation systems and multi-anion systems

多阳离子系统和多阴离子系统两种情况下非SiO2介电界面形成偶极层的机会

• 发表时间: 2017
• 作者: Fei Jiayang;Kita Koji;Jiayang Fei and Koji Kita
• 通讯作者: Jiayang Fei and Koji Kita