平动能对激光诱导气-固表面蚀刻反应的增强效应

本文采用超声分子束和时间分辨质谱技术研究了入射分子平动能对激光诱导气-固表面反应的增强效应. 对于由可见激光(56 nm)诱导的Cl_2与Ge(111)、Si(111)和GaAS(100)表面蚀刻反应, 研究发现提高Cl_2分子的入射平功能将明显地增加反应产率, 而且都存在一个入射平动能的反应阈值, 其数值为5～7 kJ·mol~(-1). 此外, 从反应产物的飞行时间谱测得入射分子平动能对产物平动温度的影响. 这些结果可以通过平动能促进Cl_2分子在表面上解离化学吸附过程来解释。

Enhancement Effect of Translational Energy on Laser Induced Gas-Surface Etching Reactions

The enhancement effect of translational energy of incident molecules on the laser induced gas-surface reactions is studied using a CW supersonic molecular beam technique coupled with time-resolved mass spectrometry. For the visible (560 nm) lasre induced etching reactions of Cl_2 with Ge(111), Si(111) and GaAs(100) surfaces the reaction yields increase obviously with increasing translational energy of incident Cl_2 molecules. There appears to be a translational energy threshold which has a value of 5—7 kJ·mol~(-1) for different etching reactions. Moreover, the dependence of the translational temperatures of the desorbed reaction products on incident translational energy of Cl_2 molecules is investigated by the measured TOF spectra of the products. The results can be explained by the promotion of dissociative chemisorption Cl_2 molecules on semiconductor surface with raising of the incident Cl_2 translational energy.