Characterization of Semiconductor Surfaces by Ultraviolet Photoelectron Yield Spectroscopy in Ambient Air

利用双单色仪研制了高分辨率紫外光电子产额(UPY)光谱仪，并将其用于半导体常温下的表面表征。通过对不同类型硅片的高分辨UPY谱的精确测量，阐明了掺杂硅片的光电子阈值能量和光电子产额谱形状都与杂质的掺杂浓度有关，也与硅片表面有关。因此，紫外光电子产额谱适用于空气环境下半导体表面的表征。利用UPY技术对硅片表面在空气中的氧化过程进行了现场监测，并对氧化速率和氧化过程进行了研究。对于Si(111)面，观察到了氧化层的连续生长，而不是其他工作人员提出的表面氧化物的逐层生长。用高分辨UPY技术表征了Ru络合物在空气/水界面上的朗缪尔层，并用光电子阈值能表征了Ru络合物的表面结构。

High resolution ultraviolet photoelectron yield (UPY) spectrometer was developed by using a double monochromator and was applied for the characterization of semiconductor surfaces in ambient condition. By the precise measurement of high resolution UPY spectra of various kinds of Si wafers, it was elucidated that both the photoelectron threshold energy and the shape of the photoelectron yield spectra of the doped Si wafers depended on the doping concentration of impurities and also on the facet of the Si wafers. Therefore it was concluded that ultraviolet photoelectron yield spectroscopy was applicable to the characterization of semiconductor surface in air condition. The oxidation of Si wafer surface in air was in situ monitored by UPY technique and the oxidation rate and the process was studied. Continuous growth of the oxide layer in stead of the layer by layer growth of the surface oxide proposed by other workers was observed for Si(111) facet. High resolution UPY technique was also applied for the characterization of the Langmuir layer of Ru complex on the air/water interface and it was elucidated that the surface structure of the complex could be evaluated by the photoelectron threshold energy.