Early stages of the alkali-metal-promoted oxidation of silicon.
Early stages of the alkali-metal-promoted oxidation of silicon.
复制标题
碱金属促进硅氧化的早期阶段。
DOI：
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
Miranda
中科院分区：
文献类型：
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作者：
Michel;Ortega;Oellig;Asensio;Ferrón;Miranda
我们用光电子能谱和俄歇电子能谱在亚单层碱金属原子覆盖范围内研究了钾和铯促进的Si(100)2ifm模氧化反应。碱金属原子有效地促进了硅的氧化。我们的结果表明，在氧化反应过程中，表面上存在两种氧物种：一种是从一开始就与钾结合的氧原子，另一种是与硅结合的氧原子。这两种氧物种在核心能级O1s和价带光电子能谱中被检测到。氧从K转移到Si，这一过程是热激活的，通过加热衬底提高了效率。为了解释这些结果，我们提出了一个基于钾产生的局域功函数减小的模型，它降低了氧解离的活化势垒。氧与钾反应，形成一种氧化钾，有效地将氧气转移到硅。
We have studied the potassium- and cesium-promoted oxidation of Si(100)2ifmmode imeselse exttimesfi{}1 with photoelectron and Auger-electron spectroscopies in the range of submonolayer alkali-metal-atom coverages. The alkali-metal atoms efficiently promote the oxidation of silicon. Our results demonstrate that there are two oxygen species on the surface during the oxidation reaction: oxygen atoms which are bonded to potassium from the very beginning of the process and oxygen atoms bonded to silicon. These two oxygen species are detected in core level O 1s and in valence-band photoemission spectra. Oxygen is transferred from K to Si, and this process is thermally activated and its efficiency is increased by heating the substrate. To explain these results we propose a model based on the decrease of local work function produced by potassium, which reduces the activation barrier for oxygen dissociation. Oxygen reacts with potassium, forming a potassium oxide which efficiently transfers oxygen to silicon.