Beobachtung von oberflächenreaktionen mit der statischen methode der sekundärionen-massenspektroskopie. I die methode

Abstract

By combination of very small primary ion current densities (10−9 A·cm−2) on a large target area (0.1 cm2) and ultra high vacuum conditions (10−10 torr range) the secondary ion emission of an individual uppermost monolayer of a solid can be observed for several hours. This “statical method of secondary ion mass spectroscopy” (SIMS) is shown to be a powerful tool for the analysis of chemical reactions at the surface of a solid. The method is demonstrated using as an example the initial surface oxidation of metals. As an analytical tool the statical method shows some important capacities: 1. Information depth in the monolayer range 2. Isotope separation 3. Detection of chemical compounds 4. Detection of hydrogen and its compounds 5. Detection limits < 10−6 of a monolayer or < 10−14 g for many elements and compounds 6. Capacity of quantitative analysis 7. Very small disturbance of the surface during the analysis 8. Detection of changes in the concentration within the first monolayers