| Summary: | 博士 === 國立中央大學 === 光電科學研究所 === 98 === In this research, the plasma etching mechanism has been applied to DUV and transparent conductive oxide coatings.
For DUV coating, aluminum fluoride thin films have been deposited by plasma etching deposition with an aluminum target onto a room temperature substrate. For low sputtering power (30W), the best optical quality and smallest surface roughness was obtained when the AlF3 thin films were coated with O2:CF4 (12sccm:60sccm). To increase the deposition rate for industrial application, the sputtering power was increased to 200W with the best ratio of O2/CF4 gas. The results show that the deposition rate at 200W sputtering power was 7.43 times faster than that at 30W sputtering power and the extinction coefficients deposited at 200W were less than 6.8×10-4 at the wavelength range from 190nm to 700nm.To compare the deposition with only CF4 gas at 200W sputtering power, the extinction coefficient of the thin films improve from 4.4×10-3 to 6×10-4 at the wavelength of 193nm. In addition, the structure of the film deposited at 200W was amorphous-like with a surface roughness of 0.8nm. All of the residual stresses were compressive and their trends were consistent with the refractive indices. The lowest compressive stress (0.068 GPa) was obtained when the AlF3 films were prepared at 160W sputtering power. High reflective lens of aluminum with an AlF3 protective layer have been deposited by PED. The reflectance in 193nm increased from 88.2% to 91.2% and the reflectance was higher than that in recent published paper (90.3%)
For transparent conductive oxide, Fluorine-doped tin oxide films have been deposited by plasma etching deposition with Sn target. Various ratios of CF4/O2 gas were injected to enhance the optical and electrical properties of films. The transmittance result shows that the novel deposition can raise the transmittance in the UV to visible range. The extinction coefficient decreased as the CF4 to O2 ratios increased and the extinction coefficient was lower than 1.5×10-3 in the range from 400 nm to 800nm when CF4 to O2 ratios was 0.375. The refractive index decreased as the CF4 to O2 ratios increased and the largest decreased amount at 550nm was 0.21. The resistivity of fluorine-doped SnO2 films deposited by PED after annealing at 350℃ in vacuum for one hour was 1.23×10-3 Ω-cm which was 40 times smaller than undoped SnO2 (4.55×10-2 Ω-cm) and the absolute average transmittance from 400nm to 800nm was 88.48% .
All of the results indicate that this new and simple process is better than conventional thermal evaporation and sputtering when depositing DUV and TCO films and it offers excellent potential for the application of manufacture in the real-world industry.
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