硅—二氧化硅界面过渡区的XPS研究

本文报道了用X射线光电子能谱的角度效应研究硅-二氧化硅界面过渡区的结果。样品为(111)取向的硅单晶片上低温(700℃)氧化生成的超薄氧化膜,膜的厚度不大于50?。氧化膜与单晶衬底中Si_2p光电子谱峰之间的化学位移(δ)和强度比(I_0x/I_si)随光电子发射角(θ)的变化明显地偏离理想界面所预期的结果,表明在硅-二氧化硅的界面处存在化学比为SiO_x(0yO_4-y(0≤y≤4)型四面体。比较实验曲线与随机成键模型的计算结果,估计出过渡区的宽度不大于20?,小于Si_2p光电子在二氧化硅中的平均逃逸深度。对改变氧化时间结合Ar⁺刻蚀制得的氧化膜厚度不同的样品所作的测量,得到与角度实验相一致的结果。关键词：

THE STUDY OF THE TRANSITION REGION AT THE INTERFACE OF Si-SiO2 BY XPS

The study of the transition region at the interface of Si-SiO₂ by changing the angle of emission in XPS is reported in this paper. The sample are ultra-thin oxide film on the silicon(111) surface formed at low temperature (700 ℃), the thickness of which was less than 50?. The variation of the chemical displacement (δ) and the intensity ratio (I_0x/I_si) of the silicon 2p photoelectron peaks come from the oxide film and the single-crystal substrate with the angle of emission is contradictory with the prediction for an ideal interface model. The comparison of the experiment results with the prediction of the random-bonding model shows that there exists a transition region at the interface of Si-SiO₂ and the width of which is about 20?, less than the mean escape length of the Si2p photoelectron in SiO₂. The same results are given by the experiment of Ar⁺ ion sputtering profiles.
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