| Spectroscopic ellipsometry is a method to get the optical constants of film by the change in polarization state when linear incident light is reflected by thin film. It employs Fourier analysis to analyze the reflected light to get the difference in reflection ratio and Phase change between P-component and S-component, then further get optical constants of the film. It’s non-contacting, non-destructive and highly sensitive, widely used in scientific research and semiconductor industry.In this paper, the basic principles of spectroscopic ellipsometry, several kind of optical dispersion model and research background of nano-Si are introduced. The optical property of a30-layered (Si/SiO2)n periodic film has been Studied, which was prepared by alternatively evaporating SiO and SiO2onto a Si(100) substrate followed by annealing at1100℃. Spectroscopic ellipsometry spectrum analysis was employed to determine optical constants of the sample film by Lorentz oscillator model and Forouhi-Bloomer model. According to the experimental data, the fitting results based on the two models are in good agreement with each other, and it is also validated by the thickness of the film obtained by TEM image. The PL spectra of the three samples with different thickness clearly shows that there are two mechanisms(QC and QCLC) in the photoluminescence process. In which the later is dominant.At the end of this paper, brief summarization and outlook are given. Some problems to be solved are also proposed. |
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