Characterization of Tantalum Oxide Thin Films Prepared by Cylindrical Magnetron Sputtering: Influence of O2% in the Gas Mixture

The amorphous tantalum oxide thin films were prepared by DC reactive magnetron cylindrical sputtering onto p-type silicon (100) substrate. We report the composition and optical properties of thin films under O-2 amount variation. The sample's reflectance was measured with a UV-Vis-NIR spectrophotometer (320-850 nm). The optical characterization of thin layers was analyzed by ellipsometry in spectral region for wavelength from 250 to 850 nm to obtain the refractive index and film's thickness. The RMS roughness and grain size were investigated by atomic force microscope (AFM). Simulations to Rutherford backscattering spectroscopy (RBS) data revealed film's stoichiometry. The reflectance, refractive index, thickness, RMS roughness and grain size were found to be affected by increasing oxygen amount. We calculated the porosity of grown layers using measured refractive index at the wavelength of 633 nm.