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This Technical Report revises ISO/TR 19319:2003 - Surface chemical Analysis-Auger electron spectroscopy and X-ray photoelectron spectroscopy-Determination of lateral resolution, analysis area and sample area viewed by the analyser. The revised Technical Report gives a short introduction to basic models of image formation and introduces functions which characterize the performance of imaging instruments with respect to lateral resolution and sharpness. The determination of lateral resolution by imaging of square-wave gratings and the determination of sharpness by imaging of narrow stripes and straight edges are described in detail. Finally, physical factors affecting lateral resolution, analysis area and sample area viewed by the analyser are discussed.
Lateral resolution, also called image resolution, is the most relevant quality parameter of maps and line scans. Therefore well defined procedures for the determination of lateral resolution are required. In the surface analysis community different definitions of lateral resolution are in use and there is no generally accepted method for the determination of lateral resolution which meets the demands of the state-of-the-art in surface analysis. We propose the determination of lateral resolution by imaging of well defined square-wave gratings with finely graded periods. This method enables the real time estimation of lateral resolution and the adjustment of instrument settings with respect to lateral resolution. The effect of noise and contrast on lateral resolution has been analysed by numerically simulated images of square-wave gratings. A new resolution criterion has been developed which is based on the dip-to-noise ratio and takes into account the sampling step width by introducing a "reduced noise". The contrast transfer function has been introduced and its relation to lateral resolution in the presence of noise was analysed. For that reason an "effective cut-off frequency" was defined which is the reciprocal of the lateral resolution. Normalized values of lateral resolution and their relation to signal-to-noise ratio and sampling step width were given for Gaussian and Lorentzian line spread functions. These values enable the calculation of experimental parameters which are necessary to get a required value of lateral resolution. Finally the successful application of the proposed approach to determine lateral resolution has been demonstrated by ToF-SIMS element mapping of the certified reference material BAM-L200.
Secondary Ion Mass Spectrometry (SIMS) enables surface chemical analysis of nano-scaled objects and chemical imaging of nano-scaled details of natural or artificial objects. This review presents the state of the art in nanoscale SIMS analysis. At first a short introduction into recent instrumentation for high resolution SIMS imaging and the limiting factors of lateral resolution is given. The next section covers the chemical analysis of nanoparticles. Recent applications of nanoscale imaging SIMS in geology, cosmochemistry, materials research, cellular biology, ecology and medical research are summarized and illustrated by examples.
Further progress in the spatial resolution of X-ray microscopes is currently impaired by fundamental limitations in the production of X-ray diffractive lenses. Here, we demonstrate how advanced thin film technologies can be applied to boost the fabrication and characterization of ultrahigh resolution X-ray optics. Specifically, Fresnel zone plates were fabricated by combining electron-beam lithography with atomic layer deposition and focused ion beam induced deposition. They were tested in a scanning transmission X-ray microscope at 1.2 keV photon energy using line pair structures of a sample prepared by metalorganic vapor phase epitaxy. For the first time in X-ray microscopy, features below 10 nm in width were resolved.