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Studies on Carrier Trap Levels at Ultrathin SiO_2/Si Interface and Its Relation with Microscopic Structures

超薄SiO_2/Si界面载流子陷阱能级及其与微观结构的关系研究

基本信息

批准号：
10450020
负责人：
HATTORI Takeo
金额：
$ 6.66万
依托单位：
Musashi Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450020/
关键词：
silicon oxide surface roughness interface states interface dipole first principle molecular orbital calculation interface structure elastic scattering oxidation mechanism 活性酸素原子酸化速度価電子帯オフセットダイポール相互作用 Si-SiO_2 界面構造非弾性散乱光電

项目摘要

(1) Below 900℃ the oxidation-induced-stress causes the increase in surface roughness. Furthermore, the surface roughness of oxide formed on Si (100) oscillates with period in thickness of 0.19 nm in accordance with periodic changes in the interface structures. (2) The interface roughness at SiO_2/Si (100) interface produces the interface states. In addition, the interface states correlated with SiO_2/Si (111) interface structures were detected. (3) The energy difference between the bonding states in the valence-band and the O 2s core-level is larger than the corresponding difference for the bulk SiO_2 by about 0.2 eV.According to a first-principle molecular orbital calculations this difference can be attributed to a narrow intertetrahedral bond angle of about 135 degrees near the SiO_2/Si interfaces. Furthermore, the valence-band offset differs by about 0.17 eV between the two types of atomic structures at the interface defined by the Si atoms in intermediate-oxidation states. Accordin … More g to a first-principle molecular orbital calculations this difference can be attributed to smaller interface dipole at the interface which is characterized as containing a maximum amount of Si atoms in 3+ oxidation states (Si^<3+>) than that at the interface which is characterized as containing a maximum amount of Si atoms in 1+ oxidation states (Si^<1+>) through the depolarization effect. (4) It was found from the Monte Carlo calculation of path of elastically and inelastically scattered Si 2p photoelectrons in silicon oxide for the simulation of oxidation-induced changes in photoelectron diffraction patterns that the total elastic scattering cross-section and the inelastic scattering cross-section are 1.54×10^<-20> and 1.26×10^<-20> m^2, respectively. (5) At the same oxidation condition the oxidation rate changes periodically with the progress of oxidation and decreases significantly at specific interface structures. In other words, the oxidation rate is influenced by the SiO_2/Si interface structures. Less

(1)900℃以下，氧化应力导致表面粗糙度增大。此外，在Si(100)上形成的氧化物的表面粗糙度根据界面结构的周期性变化以0.19nm厚度的周期振荡。 (2)SiO_2/Si(100)界面处的界面粗糙度产生界面态。此外，还检测到了与SiO_2/Si(111)界面结构相关的界面态。 (3) 价带和O 2s 核能级的键态之间的能量差比块体SiO_2的相应差值大约0.2 eV。根据第一原理分子轨道计算，这种差值可归因于SiO_2/Si界面附近约135度的窄四面体间键角。此外，在由处于中间氧化态的Si原子定义的界面处，两种类型的原子结构之间的价带偏移相差约0.17eV。根据第一原理分子轨道计算，这种差异可归因于通过去极化效应，在特征为包含最大数量的3+氧化态（Si^<3+>）Si原子的界面处的界面偶极子小于在特征为包含最大数量的1+氧化态（Si^<1+>）Si原子的界面处的界面偶极子。 (4)通过对氧化硅中弹性和非弹性散射Si 2p光电子路径的蒙特卡罗计算，模拟氧化引起的光电子衍射图样变化，发现总弹性散射截面和非弹性散射截面分别为1.54×10^<-20>和1.26×10^<-20>m^2。 (5)在相同的氧化条件下，氧化速率随着氧化的进行而呈周期性变化，并在特定的界面结构处显着降低。换句话说，氧化速率受SiO_2/Si界面结构的影响。较少的