Quantitative electron microprobe determination of oxygen in metal layers covered by surface oxide films

Abstract

Abstract A special electron microprobe data reduction procedure permits the determination of oxygen in vacuum‐deposited metal layers independent of the surface oxide layer, the mass thickness of which is simultaneously calculated. The method combines measurements of O Kα x‐rays at two values of the primary electron energy in the range 5–12.5 keV, which correspond to different depth distributions of x‐ray production. The measured data are evaluated by calibration curves derived from Gaussian Φ(ρ z ) depth distribution functions. Test analyses have been performed on amorphous metal layers with thicknesses of 0.5–1.5 μm. Typical concentrations of incorporated oxygen found ranged from 0.1 to 5 wt‐%. The influences of surface oxide films with mass thicknesses of 1–30 μg cm −2 were studied by annealing experiments in agreement with the results derived from oxygen depth profiles measured by secondary ion mass spectrometry.