Role of hydrogen for the elastic properties of alumina thin films

Abstract

We describe the role of the presence of hydrogen on the elastic properties of AlxOyHz (0.32⩽x⩽0.4; 0.54⩽y⩽0.6; 3×10−4⩽z⩽0.14) films. The films were deposited by reactive magnetron sputtering in an Ar/O2/H2O discharge and were studied by Rutherford backscattering spectrometry, nuclear resonance analysis, selected area electron diffraction, as well as nanoindentation. As the hydrogen concentration is increased from 0.03% to 13.9% the measured elastic modulus value is reduced by approximately 53%. The measured elastic modulus is in excellent agreement with our electronic structure calculations. The large scattering in the reported values of the elastic properties of amorphous alumina thin films can readily be understood by hydrogen incorporation during synthesis.