RF reactive Magnetron Sputtering으로 제조한 TiO2 박막의 구조 및 광학적 특성

Abstract

Titanium oxide films were prepared by RF reactive magnetron sputtering. The effect of sputtering conditions on structural and optical properties was investigated systemically as a function of sputtering pressure(5~20m Torr) and O2/Ar flow ratio(0.08~0.4). The results of the X-ray diffraction showed that all films had only the anatase TiO2 phase. At low sputtering pressure and O2/Ar flow ratio, the films had preferred orientations along [101] and [200] directions. As the sputtering pressure and O2/Ar flow ratio increased, the intensity of the 101 and 200 diffraction peaks decreased grdually. The microstructure of the sputtered films showed the fine grain size (20nm~50nm) and columnar microcrystals perpendicular to the substrate. With increasing the sputtering pressure and decreasing O2/Ar flow ratio, the sputtered films showed the more porous columna structure. XPS analysis showed that stoichiometric TiO2 films were deposited at 7 m Torr sputtering pressure and 0.2 O2/Ar flow ratio. The results of the X-ray diffraction showed that all films had only the anatase TiO2 phase. Ellipsometeric analysis showed that the refractive index increased from 2.32 to 2.46 as the sputtering pressure decreased. The packing density calculateed using the refractive index varied from 0.923 to 0.976, indicating that TiO2 films became denser as the sputtering pressure decreased.