SiO2 - TiO2 Thin Film for Integrated Optics Fabricated by the Sol-Gel Technique

In this paper the fabrication process and optical measurements of sol-gel SiO2-TiO2 thin films are presented. The first part is devoted to the basics of sol-gel technique, where fabrication of silica-titania films is shortly described. Investigated layers were obtained from three different precursors: tetraethyl orthosilicate (TEOS), tetrabutoxytitanate (TNBT) and titanium isopropoxide (TIPO), mixed in various amounts in order to tailor the refractive index of a layer. Sol-gel films were coated by dipcoating method on silicon substrate with 1 μm SiO
₂
optical substrate in the first case, and on bare silicon substrate in the second case. Thickness and refractive index of deposited layers was measured at 632.8 nm wavelength by use of ellipsometry. Refractive index dependence of SiO
₂
-TiO
₂
composition in sol-gel thin film is presented.