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

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(ρz) 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.

X‐ray fluorescence analysis for oxygen on and in materials

“…the depth giving two thirds of the total 0 K x-ray signal). For elemental materials, L2,3 has been calculated using Eqn ( 5 ) and plotted as a function of atomic number 2 in Fig. 3 for I,!I = 45", the angle used in our experimental arrangement.…”

X-ray spectrometry

“…Considerations of Love et al (308) on quantitative ED EPXMA for very light elements led to the following practical conclusions: (1) a thin aluminized plastic window detector is better than a windowless detector, (2) a low electron accelerating voltage is preferable, e.g., less than 15 kV, (3) low input count rates (less than 2000 counts/s) should be employed, and (4) the duration of an analysis should be timed manually. A special electron microprobe data reduction procedure has been used by Willich et al (309) for the determination of oxygen in vacuum-deposited metal layers covered by surface oxide films. The method combines measurements of O Ka X-rays at two primary electron energies in the range 5-12.5 keV, which correspond to different depth distributions of X-ray production.…”

Reference-free evaluation of thin films mass thickness and composition through energy dispersive X-ray spectroscopy

“…Since the first pioneering measurements of 𝜙(𝜌𝑧) curves in 1951 [4] considerable effort has been expended on developing semiempirical models that properly predict the 𝜙(𝜌𝑧) functions [5]; this resulted in the first commercial reliable software in the '90s [6][7][8]. The optimization of the models continues till today, and a range of software which characterize stratified samples are available [9,10].…”