Study of the influence of some physical parameters on sol-gel derived TiO2 thin films

We present some physical parameters that affect the deposition of TiO2 films by the sol-gel method. A set of solutions with different TiO2 concentrations has been prepared. After synthesis of a set of TiO, films by spin coating at different spinning speeds, the films were annealed at different temperatures. The viscosities of the start solutions were measured by a viscometer. The thickness of the films and their refractive index were measured by a monochromatic ellipsometer. The results showed that the thickness is decreasing exponentially with increasing spinning speed and decreasing linearly with temperature according to the relation d(nm) = 104 - 0.125 T(degreesC) + 322e(-S/900). The thickness of the films ranges from 56 to 129 nm. The refractive index is decreasing with the spinning speed and increasing with the temperature according to the relation n = 1.791 + 6.107x10(-4)T(degreesC) + 1.733e(-S/600). Th, refractive index of the prepared films ranges from 1.89 to 2.125 depending on annealing temperature and spinning speed. The viscosity of the start solutions increased with increasing the TiO, concentration and the aging time. One week, after preparing the solutions the viscosity was found to be in the range of 1.4 to 4.4 mPa.s depending on the concentrations.