| Summary: | 博士 === 國立中央大學 === 光電科學研究所 === 94 === The properties of SiO2 thin films deposited by different process and from different starting material were discussed and compared. Three processes -E-beam gun evaporation, Ion beam sputtering, and magnetron sputtering- were used to deposit SiO2 thin films, and Si and SiO2 were used as starting materials. The influences of ion beam assisted deposition (IAD) and its working gas were also discussed. The SiO2 thin films were then measured by UV-VIS spectrophotometer, FTIR, stress measurement interferometer, AFM, SEM, and contact angle measurement instrument to analyze the microstructure, optical, mechanical, and chemical properties.
The results showed that the SiO2 thin films had the best optical properties in UV region when they were deposited by E-beam gun evaporation with IAD; the properties were still good when deposited by magnetron sputtering; when deposited by ion beam sputtering, the properties were worse. The properties were very good in visible region when the SiO2 thin films were deposited by all of these three processes, and the extinction coefficients of all SiO2 thin films were smaller then 3x10-5. The roughness of the SiO2 thin films were the best when deposited by ion beam sputtering, the roughness increased when deposited by magnetron sputtering, and the roughness were the worst when deposited by E-beam gun evaporation. The results of FTIR measurement shown that all the SiO2 thin films were well stoichiometric, exclude the case of the SiO2 thin films deposited by E-Beam gun evaporation without IAD and used Si as the starting material for the Si2O3 bonding structure was observed in the composition and the case by the same process but used SiO2 as the starting material for the Si-OH bonding structure was observed. For the mechanical properties, all the SiO2 thin films showed the compressive stress, and the quantities of stress were the smallest when deposited by magnetron sputtering, those were bigger when deposited by ion beam sputtering, and those were the biggest when deposited by E-beam gun evaporation. From the contact angle measurement results, the SiO2 thin films deposited by ion beam sputtering had the smallest surface energy, which meant that the films were more durable, and the other SiO2 thin films were bigger.
In this research, we discussed and compared the properties of SiO2 thin films deposited by different processes in a completed arrangement. It gives good references for deposit SiO2 thin film in different conditions or for special need. For instance, use E-beam gun evaporation to deposit SiO2 thin films for UV coating; use ion beam sputtering to deposit SiO2 thin films for ultra-low loss laser mirror; use magnetron sputtering to deposit SiO2 thin films for low stress or coating on plastic substrate.
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