Thin Film Comprising Titanium Oxide as Main Component and Sintered Compact Sputtering Target Comprising Titanium Oxide as Main Component

Abstract

A thin film comprising titanium oxide as its main component includes titanium, oxygen and copper, content of Ti is 29.0 to 34.0 at % and content of Cu is 0.003 to 7.7 at % or less with remainder being oxygen and unavoidable impurities. A ratio of oxygen component to metal components, O/(2 Ti+0.5 Cu), is 0.96 or higher. The thin film has a high refractive index and low extinction coefficient. A sintered compact sputtering target suitable for producing the foregoing thin film is also provided and can be used to obtain a thin film with superior transmittance and low reflectance and which is effective as an interference film or protective film of an optical information recording medium, and to obtain a thin film that can be applied to a glass substrate; that is, a thin film that can be used as a heat ray reflective film, antireflection film, and interference filter.

1 . An optical interference film or a protective film of an optical information recording medium which is formed by performing DC sputtering to a target comprising titanium oxide as its main component, wherein the film includes titanium, oxygen and one or more types of metal M selected from cobalt, nickel, palladium and gold, content of Ti is 29.0% or higher and 34.0 at % or less and content of M is 0.003 at % or higher and 7.7 at % or less with the remainder being oxygen and unavoidable impurities, and ratio of oxygen component to metal components, O/(2 Ti+M), is 0.95 or higher. 
     
     
         2 . The optical interference film or the protective film of an optical information recording medium which is formed by performing DC sputtering to a target comprising titanium oxide as its main component according to  claim 1 , wherein a refractive index in a wavelength region of 400 to 410 nm is 2.60 or higher. 
     
     
         3 . The optical interference film or the protective film of an optical information recording medium which is formed by performing DC sputtering to a target comprising titanium oxide as its main component according to  claim 2 , wherein an extinction coefficient in a wavelength region of 400 to 410 nm is 0.1 or less. 
     
     
         4 . The optical interference film or the protective film of an optical information recording medium which is formed by performing DC sputtering to a target comprising titanium oxide as its main component according to  claim 3 , wherein the extinction coefficient in the wavelength region of 400 to 410 nm is 0.05 or less. 
     
     
         5 . The film according to  claim 1 , wherein an extinction coefficient of the film in a wavelength region of 400 to 410 nm is 0.1 or less. 
     
     
         6 . The film according to  claim 1 , wherein an extinction coefficient of the film in a wavelength region of 400 to 410 nm is 0.05 or less. 
     
     
         7 . A sintered compact target for DC sputtering for forming an optical interference film or a protective film of an optical information recording medium comprising titanium oxide as its main component, wherein the target includes one or more types of metal M selected from cobalt, nickel, palladium and gold and comprises, as its main component, titanium oxide made of titanium, oxygen and unavoidable impurities as a remainder thereof, the respective components have a composition ratio of (TiO 2-m ) 1-n M n  (provided that 0≦m≦0.5 and 0.0001≦n≦0.2), and the target has a specific resistance of 100 Ωcm or less.