Reactions of Atoms

Abstract

computer deconvolution. The broad N I s line also indicates that nitrogen does not occur only in one state of binding.Since the Auger effect can also be excited by electron bombardment, the question arises whether it may be possible to couple the scanning electron microscope and an electron spectrometer. For commercial scanning electron microscopes this is not practicable because of the poor vacuum. The pressure must be lowered to at least 10-* torr, otherwise only contamination layers will be analyzed. This will happen particularly in the case of Auger lines of low kinetic energy since the escape depth is then also reduced. The Auger effect can in fact be observed on operation of a scanning electron microscope at an improved vacuum (ion getter pumps, metal seals) and it has already been utilized in surface analysis of metals[''].Difficulties arise in the case of insulators due to electrostatic charging. There is the additional danger of destruction of the surface layer by intense electron bombardment, which is greater than the possible damage by X-rays. Measurement of chemical shifts is feasible only with sharp Auger lines. The large line width frequently observed stems from the width of the outer energy level from which the Auger electron is usually liberated. Thus a combination of electron microscope and electron spectrometer is possible in principle; in practice, however, such a system will be used only for those problems which require surface analysis with high spatial resolution and which cannot be solved by X-ray fluorescence methods.