Spectroscopic ellipsometry and x-ray photoelectron spectroscopy of La2O3 thin films deposited by reactive magnetron sputtering

Abstract

Lanthanum oxide (La2O3) films were grown by the reactive dc magnetron sputtering and studied their structural, chemical and optical parameters. La2O3 films were deposited onto Si substrates by sputtering La-metal in a reactive gas (Ar+O2) mixture at a substrate temperature of 200 °C. Reflection high-energy electron diffraction measurements confirm the amorphous state of La2O3 films. Chemical analysis of the top-surface layers evaluated with x-ray photoelectron spectroscopy indicates the presence of a layer modified by hydroxylation due to interaction with atmosphere. Optical parameters of a-La2O3 were determined with spectroscopic ellipsometry (SE). There is no optical absorption over spectral range λ=250–1100 nm. Dispersion of refractive index of a-La2O3 was defined by fitting of SE parameters over λ=250–1100 nm.