Evolution of infrared spectra and optical emission spectra in hydrogenated silicon thin films prepared by VHF-PECVD

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...

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Published inChinese physics B Vol. 20; no. 7; pp. 440 - 445
Main Author 侯国付 耿新华 张晓丹 孙建 张建军 赵颖
Format Journal Article
LanguageEnglish
Published 01.07.2011
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ISSN1674-1056
2058-3834
DOI10.1088/1674-1056/20/7/077802

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Summary: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^*/Ha 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 p-c-SiH formation have been analyzed based on the variation of Ha 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.
Bibliography:Hou Guo-Fu, Geng Xin-Hua, Zhang Xiao-Dan, Sun Jian, Zhang Jian-Jun, Zhao Ying Institute of Photo-electronics, Nankai University, Tianjin 300071, China
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^*/Ha 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 p-c-SiH formation have been analyzed based on the variation of Ha 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.
Fourier transfer infrared spectroscopy, optical emission spectroscopy, Si H bonding con-figuration, oxygen impurity
11-5639/O4
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ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/20/7/077802