No abstract available

[en] When an insulating sample on which a conducting grid has been deposited was bombarded with primary ions, the equilibrium potential of the surface was different than that of the reference grid. This charge effect has been studied by ion microscopy employing either a varying magnetic field or the counter-field of the electrostatic mirror

[en] Design and development of a new scanning ion-microprobe using a quadrupole mass-filter as secondary ion analyser is described. The differentially pumped primary-ion column produces a minimum spot-size of below 4μm(less than 2μm for 50% definition) and can achieve maximum current densities of up to 40 mA/cm² (10 keV 0₂+). Positive or negative primary and secondary ions may be used for analysis. The whole system can be baked and allows ultrahigh voltage conditions to be obtained in the sample chamber. Applications of the elemental mapping capability of the instrument are described. (auth.)

[en] The nuclear microprobe is an instrument used to determine the atomic composition of the near-surface region of materials and is finding increasing use in a wide variety of scientific areas. When a scanning microprobe uses a depth-sensitive ion-beam analysis technique such as RBS, three dimensional analyses can be performed. This paper reviews current nuclear microbeam applications with emphasis on results involving such multidimensional profiling. 80 refs., 5 figs

[en] Megaelectronvolt-Secondary Ion Mass Spectrometry (MeV-SIMS) is an emerging ion beam analysis technique for molecular speciation and submicrometer imaging. Following the construction of different experimental setups a systematic investigation on the dependence of secondary ion yields on experimental parameters is crucial. Without this knowledge, results are hard to interpret as surface roughness, scan size and the position on the sample can influence the secondary ion count and misleading images can be obtained. Additionally, to achieve better reproducibility the optimal experimental conditions need to be well known. In this work, we present the results of investigations into the influence of the main experimental parameters on the secondary ion yield.

[en] An apparatus is designed for local surface analysis of a target sample in which an ion probe is directed to the target for sputtering particles. A chamber having walls heated to a high temperature (above 2200⁰K as a rule) collects sputtered particles. The particles entering the chamber are subjected to successive adsorptions and desorptions before they leave the chamber for entry into a mass spectrometer. Scanning may be provided as in conventional SIMS systems. 15 claims, 6 figures

[en] Microprobe techniques using scanned, focused MeV ions are routinely used in Livermore for materials characterization. Comprehensive data analysis with these techniques is accomplished with the computer software package IMAP, for Ion Micro-Analysis Package. IMAP consists of a set of command language procedures for data processing and quantitative spectral analysis. Deconvolution of the data is achieved by spawning sub-processes within IMAP which execute analysis codes for each specific microprobe technique. IMAP is structured to rapidly analyze individual spectra or multi-dimensional data blocks which classify individual events by the two scanning dimensions, the energy of the detected radiation and, when necessary, one sample rotation dimension. Several examples are presented to demonstrate the utility of the package

[en] The methods employed to overcome the difficulties encountered in the study of thin insulating layers are described; modification of the sample voltage to compensate the surface charge; presence of oxygen near the sample which allows the same rate of ionisation for the oxide and the metal; crater shape adequate to reduce redeposition phenomena; bombardment by neutral particles to avoid the migration of some impurities under the influence of electric fields created by electric charges on the surface

[en] To improve the depth resolution in secondary ion mass spectrometry (SIMS) depth analysis by reducing the crater-edge effect, samples with mesa-structure projections were prepared by photolithography. The depth profiles of boron implanted into silicon were studied by comparing those for a conventional flat sample and the mesa-structure sample while systematically changing the gate area ratio. The mesa-structure preparation was very useful for eliminating undesired ions originating from the crater edge or surroundings of the analyzed area; it therefore led to remarkable improvement in the depth profiles while keeping a low background level of the order of 10^-1 cps and high dynamic range of the order of 10⁵ even at a high gate area ratio of more than 30%. As a result, a good depth profile for a 4 μm x 8 μm sample was successfully achieved by this method

[en] Image-contrast in secondary-ion micrographs, particularly from non-planar samples, may be determined not only by the distribution of elemental concentrations across the image field but also by artefact contrast effects such as topographic, chromatic or matrix contrast. An algorithm is described which can be used to remove artefact contrast and which may allow true elemental concentration maps to be obtained from secondary-ion images. The algorithm is implemented on a PDP 11/34 minicomputer and is applied to digitized ion-micrographs obtained by a scanning ion-microprobe. (auth.)