STOICHIOMETRIC DETERMINATION OF THIN METAL-OXIDE FILMS

The stoichiometry of thin metal oxide films was investigated by using PIXE with an ultrathin window X-ray detector, and proton elastic scatt ering. As an example, measurements of the O/Zr concentration ratio for electron beam evaporated ZrO2-x films deposited on Al substrates are reported. The relative detection system efficiency for oxygen K X-rays to zirconium L X-rays has been determined experimentally by normaliza tion to proton elastic scattering. The oxygen peak in the backscattere d spectrum is resolved from the aluminum substrate peak for the proton energy of 4.6 MeV. In this energy region the oxygen cross section for elastic scattering has a broad resonance behaviour, and varies rather smoothly inside the energy interval of 20 keV, corresponding to the e nergy loss inside thin film (thickness approximately 400 nm). For PIXE measurements 2.6 MeV protons have been used.