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A series of hydrogenated silicon thin films with varying silane concentrations have been deposited by using very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method.The deposition process and the silicon thin films are studied by using optical emission spectroscopy (OES) and Fourier transfer infrared (FTIR) spectroscopy,respectively.The results show that when the silane concentration changes from 10% to 1%,the peak frequency of the Si-H stretching mode shifts from 2000 cm-1 to 2100 cm-1,while the peak frequency of the Si-H wagging-rocking mode shifts from 650 cm-1 to 620 cm-1.At the same time the SiH /H α intensity ratio in the plasma decreases gradually.The evolution of the infrared spectra and the optical emission spectra demonstrates a morphological phase transition from amorphous silicon (a-Si:H) to microcrystalline silicon (μc-Si:H).The structural evolution and the μc-Si:H formation have been analyzed based on the variation of H α and SiH* intensities in the plasma.The role of oxygen impurity during the plasma process and in the silicon films is also discussed in this study.
A series of hydrogenated silicon thin films with varying silane concentrations have been deposited by using very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. Deposition process and the silicon thin films were using by optical emission spectroscopy (OES) and Fourier transfer infrared (FTIR) spectroscopy, respectively. These results show that when the silane concentration changes from 10% to 1%, the peak frequency of the Si-H stretching mode shifts from 2000 cm-1 to 2100 cm-1, while the peak frequency of the Si-H wagging-rocking mode shifts from 650 cm -1 to 620 cm -1. At the same time the SiH / H α intensity ratio in the plasma decreased gradually. The evolution of the infrared spectra and the optical emission spectra demonstrates a morphological phase transition from amorphous silicon (a-Si: H) to microcrystalline silicon (μc-Si: H). The structural evolution and the μc-Si: H formation have been analyzed based on the variation of H α and SiH intensities i n the plasma. The role of oxygen impurity during the plasma process and in the silicon films is also discussed in this study.