硅基片上微米厚度SiO2膜的斜入射红外反射透过谱分析

介绍了硅基片上具有微米厚度的SiO2膜在斜入射情况下的红外反射透过谱测量结果,发现在900~1250cm-1波段内的结果有别于一般的透射谱,出现了峰位基本不变的1100cm-1反射峰。随厚度增大,1100cm-1峰和1200cm-1凹谷的降低逐渐变为迟缓。当厚度达到2μm以上后,1075~1250cm-1谱线的变化已不再明显。通过分析表明,结果中包含了SiO2膜的表面反射谱和SiO2膜层的吸收谱。当膜厚达到微米量级而引起较大吸收时,表面反射谱的贡献相当明显。此时,对该段谱线的分析不能仅考虑膜层的吸收。

Analysis of Reflective IR Transmittance Spectra at Oblique Incidence of Micrometer SiO2 Films on c-Si Substrate

The reflective infrared transmittance spectra at oblique incidence of SiO_2 films deposited on c-Si wafer have been measured. The thickness of the films was micrometer quantity. The spectra showed many differences from the common transmittance (or (Absorption)) spectra in the range of 900-1 250 cm~(-1). The reflectivity peak at 1 100 cm~(-1) was found and its position was essentially fixed. With the (thickness) (increased,) the drop of peak at 1 100 cm~(-1) and hollow at 1 200 cm~(-1) became gradually slow. As the (thickness) increased to be over 2 micrometers, the shape of the spectra in 1 075-1 250 cm~(-1) did not change obviously. The analysis showed that the measured spectrum was composed of reflectivity spectrum and Absorption spectrum of the SiO_2 film, which occurred at Air/SiO_2 interface and SiO_2 layer respectively. When the (thickness) was over one micrometer and the film had considerable Absorption, the contribution from reflectivity spectrum became very obvious. So the Absorption is not the only factor in the analysis of these spectra.