Initial Stage of Oxidation of Si(001)-2×1 Surface Studied by X-Ray Photoelectron Spectroscopy
Initial Stage of Oxidation of Si(001)-2×1 Surface Studied by X-Ray Photoelectron Spectroscopy
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X射线光电子能谱研究Si(001)-2×1表面氧化初期
DOI：
10.1143/jjap.39.560
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发表时间：
1998
影响因子：
1.5
通讯作者：
R. Shimizu
中科院分区：
文献类型：
--
作者：
Y. Harada;M. Niwa;T. Nagatomi;R. Shimizu
利用X射线光电子能谱（XPS）研究了Si（001）-2 ×1重构表面在不同氧暴露条件下的表面组成和原子尺度上的氧化过程。我们已经证明，初始氧化过程是由我们的修改后的随机键合逐层机制解释。低氧化物含量（Si 1+：Si 2+：Si 3+）随着O2暴露的增加从1：0：0变化到2：1：0到3：2：1。总的低氧化物饱和到SiO 5/6，这是逐层氧化的中间状态，并且在二维SiO2岛成核之前达到亚稳态。桥连氧原子与顶部氧原子的比例约为4：1。在顶部站点的氧的部分随着O2暴露的增加而减少。氧原子优先插入二聚体下原子的背键。
The surface composition of a Si(001)-2 ×1 reconstructed surface after various O2 exposures and the oxidation process in an atomic scale based on the experiments using X-ray photoelectron spectroscopy have been investigated. We have demonstrated that the initial oxidation process is explained by our modified random bonding layer-by-layer mechanism. The suboxide contents (Si1+:Si2+:Si3+) change from 1:0:0, to 2:1:0 to 3:2:1 with increasing O2 exposure. The total suboxide saturates to SiO5/6 which is an intermediate state of the layer-by-layer oxidation, and to a metastable state prior to the nucleation of the two-dimensional SiO2 islands. The ratio of the bridging oxygen atoms to the on-top oxygen atoms is approximately 4:1. The portion of oxygen at the on-top site decreases with increasing O2 exposure. The oxygen atoms preferentially insert into the back bond of the dimer down-atom.