$TiO_2$ thin films were deposited on corning glass and P type Si wafer by DC reactive magnetron sputtering using Ti metal target at 300℃ and oxygen/argon flow ratio is 10%. The experiment was practiced with thickness of the films increasing.
Anatase structure is observed from X-ray diffraction pattern. And there is no different X-ray diffraction pattern with thickness. Refractive index abruptly increases about 100nm thickness and decrease as thickness increase. Dielectric constant also increases as thickness increases. Breakdown field decrease as the thickness of $TiO_2$ thin films increase. The density and roughness was measured by GIXR (Grazing Incidence X-ray Reflectivity) method and AFM (atomic force microscopy). Breakdown field is range of 0.1~0.5MV/cm. It is not high to use insulator layers for gate oxide of MOS or ELD (Electro-Luminescent Device). So $N_2O$ plasma treatment is used to increase breakdown field of the films. After plasma treatment, leakage current properties are improved and breakdown field increases and dielectric constant decreases. Roughness decreases also. But there is no different FWHM (Full Width at Half Maximum) of A (101) peak, X-ray diffraction pattern between as deposited film and plasma treated film. So roughness is considered to be main factor related to results above.