Optical and structural properties of TiO2 films deposited from Ti3O5 by electron beam

TiO2 thin films were deposited by e-beam and the refractive index and extinction coefficient of the films were measured. When the oxygen pressure increases from 1.3X10-5 to 2.2X10-4Torr, while the substrate temperature (300+/-10 deg C) and the depositing rate (0.1nm/s) were kept constant, the refractive index of the films decreases from 2.41 to 2.12 (at lambda=550nm). The structures of the films were investigated by X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM). XRD measurements revealed that the films deposited in a higher substrate temperature (300+/-10 deg C) were partially crystalline. The AFM investigation confirmed that lower oxygen pressure, higher deposition rate and higher substrate temperature produce a higher surface roughness of TiO2 film. When the deposition rate (0.1nm/s) and the substrate temperature (300+/-10 deg C) were kept constant, and the oxygen pressure was varied from 1.3X10-5 to 2.2X10-4Torr, the roughness (Root-Mean-Square) of as-deposited films was changed from 3.53 to 1.91nm.