Difference between bulk and thin film densities of metal oxide and fluoride films studied by NRA depth profiling techniques

Abstract

Nuclear reaction analysis techniques have been used to study the difference between bulk and thin film densities of different dielectric (WO 3, MgF 2, NdF 3, LaF 3 and ThF 4) thin films. Thicknesses of the films were measured by optical methods. The 18 O( p, α) 15 N reaction was used at 730 keV to profile WO 3 prepared with different thicknesses on a tantalum backing by thermal evaporation of natural WO 3. We have also successfully tested the 18 O( p, α) 15 N reaction at the 629 keV ( Γ=2.1 keV) resonance for the same purpose. Excitation function measurements of the reaction was performed around the resonant energy at a detection angle of 150°. In order to obtain the oxygen profiles of the thin films non-resonant part of the excitation function was deconvoluted using the known cross-section data of the reaction. Also, we studied different films of MgF 2, NdF 3, LaF 3 and ThF 4 using the 483.85 keV resonance in the 19 F( p, αγ) 16 O reaction.