在矽晶表面的矽與矽原子振動狀態,可藉由研究多孔矽(porous silicon)的兩種光學分析方法加以了解。傅立葉紅外光譜(Fourier Transform Infrared Spectroscopy, FTIR)之紅外光吸收及拉曼散射光譜(Raman Scattering Spectroscopy)以不同之物理原理,但同樣均可研究原子與原子間之振動狀態,以分析Si-Si原子間之振動模式。本文進行了對多孔矽的陽極蝕刻及化學氧化實驗,並利用FTIR分析,發現了在一般大家所觀察得之Si-Si FTIR吸收光譜線610cm^(-1)旁有一條620cm^(-1)屬於Si-Si在晶體表面區域的振動模式吸收光譜。其與在拉曼光譜的實驗中觀測到此一振動譜線不同,我們在文中作了分析討論,以進一步了解此三種分析方法之差異及互補性。
The Si-Si surface vibrational state of porous silicon has been characterized using Fourier' Transform Infrared Spectroscopy (FTIR). Two Si-Si vibration modes of porous silicon for near surface regions and in the bulk are identified through the anodic etch and oxidization experiment. The peak of 620 cm^(-1) has been found to be varied in dependence on the porous silicon etch and oxidization and which is originated of the Si-Si atoms vibrations near surface region and on the surface of porous silicon. The peak of 610 cm^(-1) doesn't change through the experiment, and be assigned for Si-Si vibrations in bulk. Correlated atomic force microscopy (AFM) analysis show that the surface of porous silicon after oxidization is then covered by oxide, which causes the decreasing of the peak of 620 cm^(-1). The FTIR spectra reveal a red shift when the PS sample is irradiated with an extra ND: Yag laser beam. These results can give an interpretation to explain the different results of Si-Si vibrations between of Raman and FTIR spectroscopy.