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Effect of silane flow rate on structural, electrical and optical properties of silicon thin films grown by VHF PECVD technique
Hydrogenated silicon thin films deposited by VHF PECVD process for various silane flow rates have been investigated. The silane flow rate was varied from 5 sccm to 30 sccm, maintaining all other parameters constant. The electrical, structural and optical properties of these films were systematically...
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Published in: | Materials chemistry and physics 2013-08, Vol.141 (1), p.89-94 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Hydrogenated silicon thin films deposited by VHF PECVD process for various silane flow rates have been investigated. The silane flow rate was varied from 5 sccm to 30 sccm, maintaining all other parameters constant. The electrical, structural and optical properties of these films were systematically studied as a function of silane flow rate. These films were characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and UV–visible (UV–Vis) spectroscopy. Different crystalline volume fraction (22%–60%) and band gap (∼1.58 eV–∼1.96 eV) were achieved for silicon thin films by varying the silane concentration. A transition from amorphous to nanocrystalline silicon has been confirmed by Raman and FTIR analysis. The film grown at this transition region shows the high conductivity in the order of 10−4 Ω−1 cm−1.
•Silicon films grown using VHF PECVD at various Fsilane (silane flow rate).•Amorphous to nanocrystalline silicon transition at Fsilane ∼5 sccm–10 sccm.•Deposition rate increases with the increase of Fsilane.•Powder formation occurred beyond 20 sccm of Fsilane.•Film grown at 20 sccm shows max. crystalline fraction ∼60% with Eg ∼1.58 eV. |
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ISSN: | 0254-0584 1879-3312 |
DOI: | 10.1016/j.matchemphys.2013.04.028 |