Profiling of carbon, oxygen and argon contamination in sputter-deposited films using nuclear backscattering and nuclear reaction spectroscopy

Abstract

Carbon, oxygen and argon contaminations are known to play an important role in modifying the properties of surface coating films. We have profiled such elements using quantitative and non-destructive nuclear analysis techniques. Carbon and oxygen profiling is performed using nuclear backscattering of high-energy α-particles. Measurements of carbon and oxygen contamination on niobium-coated copper RF cavities used in high-energy accelerator technology are carried out. Oxygen and carbon sensitivity limits are respectively 10 15 and 5 × 10 15 atoms/cm 2 while surface depth resolutions are 30 and 25 μg/cm 2. Argon contamination profiling is performed using the 40Ar(p, γ) 41K resonant nuclear reaction at a proton incident energy of 1101.8 keV. Argon profiling in niobium films is studied: the depth resolution is around 5 μg/cm 2 while the sensitivity limit is 10 14 atoms/cm 2 within each depth resolution step.