HIGH REFRACTIVE INDEX DIELECTRIC FILM AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a high refractive index dielectric film which can be stably used as the structural material of an optical multilayer film, that is, which causes no change in the optical characteristics with time and has a low film stress. SOLUTION: The high refractive index dielectric film is formed of an amorphous material having no columnar structure and essentially comprising titanium oxide (TiOx with x satisfying 1<=x<=2) with added oxides of other metals (MOw, wherein M represents metals such as niobium and tantalum and w satisfies 1<=w). The obtained thin film is made amorphous by inhibiting the crystal growth of the titanium oxide by addition of other metal oxides although titanium oxide easily forms a crystalline structure even in a thin film state. Thus, the mixed high refractive index dielectric film containing titanium oxide and showing little temporal changes in the optical characteristics can be obtained.