氟化鎂與氟化鋁為紫外光區之光學薄膜設計與應用上常見兩種低折射率材料,在單一材料情況下,以熱蒸鍍的氟化鎂薄膜會產生微觀的柱狀結構,此結構會使得薄膜具有各向異性的性質,而氟化鋁薄膜則無結構產生,但則具有易與水反應的性質。本實驗嘗試以混合製鍍的方式,以不同混合比例製程,找出膜質特性最佳的氟化物混合薄膜,實驗中主要以橢圓偏振術的量測觀點,研究在不同混合比例下對微觀結構的影響,並探討在不同混合比例下因柱狀結構引起的雙折射性質。 Magnesium Fluoride and Aluminum Fluoride are both very popular low refraction index materials for optical thin films design in ultraviolet region. They are not very stable using for a long time, due to the microstructure and chemical properties. We tried to mix these two materials, Magnesium Fluoride and Aluminum Fluoride, and find the best deposition ratio of the mixed coatings to have better optical characteristic and chemical properties. This study is based on the measurement of ellipsometry method. Discuss the microstructure and birefringence of the mixed coatings with the composite ratio of two fluoride materials.