Näherungsformeln für den Ionisierungsquerschnitt derK-Schale durch Elektronenstoß

Hink, W.; Jessenberger, J.; Ziegler, A.

doi:10.1007/bf01395966

Cited by 6 publications

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Detection of thin surface films by electron beam microanalysis. A comparison between wavelength-dispersive and energy-dispersive microprobes

Wendt¹,

Krajewski²,

Bimberg

1976

Phys. Stat. Sol. (a)

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The detection limits of electron beam microanalysis are determined for thin evaporated films of Ti, Fe, Cu, and Ge on fused quartz substrates. Both wavelength‐dispersive and energy‐dispersive spectrometers (WDS and EDS, respectively) are used. The optimum excitation voltage is calculated on the basis of the 3σ criterion. The experimental data (Uopt = 1.6 and 1.8 for EDS and WDS, respectively, U overvoltage ratio) agree well with theoretical ones if a modified Bethe ionization cross‐section Q ∼ ln U/Um with m = 0.7 is used in the calculation. The detection limits of the WDS are in the order of 10−2 μg/cm2. They are better than those of the EDS by a factor of about 30. Using absorption filters between sample and detector and working with inclined electron incidence the detection sensitivity of the EDS can be increased by a factor of about four. The resulting improvement of the reproducibility will be demonstrated for a 170 Å CrNi resistance film. A counting time of 400 s is sufficient to measure the intensity ratio of the Kα lines of Cr and Ni with a standard deviation of 1%.

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