Self-Limitation of Native Oxides Explained
Self-Limitation of Native Oxides Explained
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DOI：
10.1007/s12633-015-9366-8
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发表时间：
2016-07-01
期刊：
影响因子：
3.4
通讯作者：
Sigmund, Wolfgang
中科院分区：
文献类型：
--
作者：
Bohling, Christian;Sigmund, Wolfgang
硅是许多表面在环境条件下会氧化的材料之一。然而，它是少数几种材料之一，其天然氧化物可以在几小时内将其生长限制在2纳米的厚度上。在这项工作中，我们通过排斥范德华力理论表明，这种自我限制至少部分是由于硅上天然氧化硅膜的固有材料性质与氧化分子之间的相互作用。这些分子不仅被阻止进入系统，而且那些进入天然氧化膜的分子被排斥在硅-氧化硅界面之外，从而阻止了氧化作用的额外生长。我们还展示了如何通过提高环境温度来克服这种排斥，从而增加氧化分子的动能，由玻尔兹曼-麦克斯韦分布计算，并允许氧化继续进行。
Silicon is one of many materials whose surface will oxidize in ambient conditions. However it is one of few materials whose native oxide will self-limit its growth in a matter of hours at a thickness of similar to 2 nm. In this work, we show through the theory of repulsive van der Waals forces that this self-limitation is due, at least in part, to the interaction between the inherent material properties of a native silicon oxide film on silicon and oxidizing molecules. These molecules are not just hindered from even entering the system at all, but those that do enter the native oxide film are repelled away from the silicon - silicon oxide interface, preventing additional growth by oxidation. We also show how this repulsion is overcome by increasing ambient temperatures to subsequently increase the kinetic energy of the oxidizing molecules, calculated by the Boltzmann-Maxwell distribution, and allow oxidation to continue.