光學鍍膜中有兩個重要的課題，一、開發具有良好光學特性、機械特性及環境穩定性的薄膜材料。二、開發新的光學多層鍍膜設計方式。而新薄膜材料的開發有助上述兩課題的研究，本文所述利用兩現有的薄膜材料混合出所需特性的混合薄膜，是一個有意義的技術。 混合膜之製鍍是使用射頻離子束濺鍍系統，為單一離子源同時轟擊兩個靶材，並利用步進馬達控制兩靶材的面積比例，以決定混合膜的成份比例。研究分為兩個部份，一、高折射率混合膜材料的研究，於實驗中使用Ta及Ti靶材製鍍出Ta2O5-TiO2混合膜，可將折射率及消光係數控制在純TiO2及Ta2O5薄膜間， Ta2O5-TiO2混合膜表面粗糙度約為0.1nm，Ta2O5-TiO2混合膜之殘留應力低於純TiO2薄膜，Ta2O5-TiO2混合膜於退火後仍是非晶結構，且混入Ta2O5後可消除TiO2薄膜於退火後之表面缺陷，使混合膜仍具有低的表面粗糙度，並可減少Ta2O5-TiO2混合膜於退火前後之殘留應力變化量，可減少高溫對薄膜機械性質的影響；二、漸變折射率混合膜之研究，於實驗中使用Ta及SiO2靶材製鍍出Ta2O5-SiO2混合膜，Ta2O5-SiO2混合膜可控制折射率變化由1.52至2.16，Ta2O5-SiO2混合膜具有低消光係數約小於10-4@550nm，Ta2O5-SiO2混合膜之表面粗糙度低於0.1nm，有較純Ta2O5及SiO2薄膜小的殘留應力值，且由實驗結果顯示，利用混合膜所製鍍之皺波折射率濾光片，會有比高低折射率材料堆疊之多層濾光片較小的殘留應力及基板變形量。上述結果可知，混合膜可作為高品質之光學鍍膜材料及漸變折射率光學鍍膜之應用。There are two important topics on optical coatings. First, we have to develop thin film materials with good optical properties, mechanical properties, and environmental stability. Second, we need to develop new methods to design optical multilayer coatings. The development of the new materials is helpful to study these two topics. Mixing two thin film materials is an interesting technology to develop new thin film materials. In this article, the radio frequency ion-beam sputtering deposition (RF-IBSD) system was used to prepare composite films. An ion source was used to bombard two targets simultaneously. The composite proportions are determined by the area ratio of two targets and the area ratio could be adjusted by moving the targets with a step motor. In this experimental have two parts. First, to study the material of high refractive index composite film, Ta2O5-TiO2 composite films prepared by Ti and Ta targets. The refractive indices and extinction coefficients of the composite films were found to be between those of the TiO2 and Ta2O5 films. The structure of the as-deposited films was amorphous, and the surface roughness was about 0.1 nm. The residual stress of the composite films was less than that of pure TiO2 film. The structure of the composite films after annealing was amorphous, with low surface roughness and slightly increased residual stress. Second, to study the gradient-index composite films, Ta2O5-SiO2 composite films were prepared by Ta and SiO2 targets. Ta2O5-SiO2 composite films with refractive indices varied from 1.52 to 2.16, and low extinction coefficient was about 10-4@550nm. All the composite films were amorphous and had surface roughness less than 0.1 nm. The residual stress and substrate deflection of rugate filter would be smaller than that of the multilayer filter which was made by stacking up alternatively with high and low refractive index materials. To sum up, the composite films could be used for high quality optical coating materials and gradient-index optical coating.
