Ellipsometric characterization of LaNiO3−x films grown on Si (111) substrates: Effects of oxygen partial pressure

Abstract

LaNiO 3−x films have been grown on Si (111) substrates under different oxygen partial pressures using radio frequency magnetron sputtering. X-ray diffraction shows that these films are polycrystalline with a highly (100)-preferential orientation. The optical properties of the LaNiO3−x films have been systematically investigated by spectroscopic ellipsometry (SE) in the wavelength range of 400–1700 nm. For interpreting the SE experimental data, a parametrized Drude and double Lorentzian oscillator dispersion relation has been used to model the optical response of the LaNiO3−x films. The relations between the optical constants of the LaNiO3−x films and oxygen partial pressure have been characterized in detail. The resistivity can be calculated by the Drude term and these ellipsometric analysis results are nearly consistent with the electrical dc measurements. The resistivity (these values are about 5.5×103 μΩ cm) obtained by spectroscopic ellipsometry shows that these films would be good to use as bottom electrodes.