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Modelling Techniques For The Quantification Of Some Electron Beam Induced Phenomena, Wk Chim, Dsh Chan, Ts Low, Jch Phang, Ks Sim, Kl Pey

Scanning Microscopy

This paper presents simulation models for quantifying the voltage contrast, cathodoluminescence and indirect specimen charging phenomena in the scanning electron microscope (SEM). The voltage contrast model comprises an electric field computation program using the finite-element approach, and a secondary electron trajectory tracking algorithm employing a linear electric field assumption. This trajectory tracking algorithm is more accurate than the conventional electron trajectory tracking algorithms which make use of a constant electric field assumption within each computation step. Using this model, results of qualitative voltage contrast effects on secondary electron trajectories in the specimen chamber of the SEM are shown. This model …

On A Nature Of Cathodoluminescence Contrast Of Fine-Dispersed Structures In The Scanning Electron Microscope, M. V. Viskov, S. K. Obyden, G. V. Saparin

Scanning Microscopy

Fine-dispersed structures (FDS) consisting of a large number of microcrystalline or amorphous particles of different sizes and shapes were examined in cathodoluminescence (CL) mode scanning electron microscopy (SEM). Line dimension of each particle (about 10 - 100 μm) was larger than the electron beam diameter as well as electron scattering volume in material under investigation. An analysis of observed images showed the existence of some peculiarities in contrast which have not been observed in the CL-images for solid specimens. The FDS CL-image topographic contrast arises as a result of detection of CL-emission from an aggregate of FDS-elements surrounding an irradiated …

Cathodoluminescence Spectroscopy: An Accurate Technique For The Characterization Of The Fabrication Technology Of Gaalas/Gaas Heterojunction Bipolar Transistors, A. C. Papadopoulo, C. Dubon-Chevallier, J. F. Bresse

Scanning Microscopy

Cathodoluminescence (CL) spectroscopy and imaging performed at low temperature have been used to qualify the heterojunction bipolar transistor fabrication technology, particularly the etching and ion implantation steps. CL has been used to optimize low defect technological processes. The protection of the active region during the insulation process has been optimized. The best result is obtained when using a bilayer of silicon nitride and photoresist. In order to minimize it, the damage induced by the etching process has also been studied. The best result is obtained when combining Ar ion beam etching and chemical etching. The possibilities to perform localized spectroscopy, …

Integrated Single Crystal Detector For Simultaneous Detection Of Cathodoluminescence And Backscattered Electrons In Scanning Electron Microscopy, Rudolf Autrata, Josef Jirák, Jiří Špinka, Otakar Hutař

Scanning Microscopy

The design of the majority of the available high efficiency cathodoluminescence (CL) detection systems allows the secondary electron (SE) and backscattered electron (BSE) image modes to be detected simultaneously to a limited degree only. The described CL-BSE detector is based on the single crystal YAG scintillator shaped as a spherical mirror which reflects photons emitted from the CL specimen and focuses them on to the entrance surface of a fibre optic light guide connected to the photomultiplier tube (PMT I). The backscattered electrons emitted from the CL specimen move through the reflecting layer of the mirror into the YAG scintillator …

Cathodoluminescence Applied To The Microcharacterization Of Mineral Materials: A Present Status In Experimentation And Interpretation, G. Remond, F. Cesbron, R. Chapoulie, D. Ohnenstetter, C. Roques-Carmes, M. Schvoerer

Scanning Microscopy

Experimentation and interpretation of cathodoluminescence (CL) microscopy and spectroscopy applied to the microcharacterization of material minerals are reviewed. The origins of the intrinsic (host lattice) and extrinsic (impurities) luminescence emissions in crystals are briefly discussed. Merits and limitations of the available techniques are illustrated. CL emission changes as a function of the incident electron dose are illustrated for the case of natural quartz and sphalerite (ZnS) crystals. These effects are discussed in terms of the development of bulk charging, production of heat, diffusion of impurities, and creation of lattice defects induced by the incident ionizing particles. Although CL emission is …

Cathodoluminescence Image Processing Of High Tc Superconductors, Z. Barkay, G. Deutscher, E. Grunbaum

Scanning Microscopy

Cathodoluminescence (CL) in the Scanning Electron Microscope (SEM) was performed for both ceramic pellets and thin films of YBaCuO high T_C superconductors. Image processing provided additional quantitative information. For single phase films, we demonstrated the possibility to create thickness maps in real time from the CL pictures. The gradual thickness variation within the sample was revealed by the histogram of the thickness image. The continuity of the film was observed at a few threshold thicknesses values, defined by the fraction of the occupied area. At the conduction threshold value, the location and width of the conducting paths could be …

Apatite - Cholesterol Agglomerates In Human Atherosclerotic Lesions, Sara Sarig, Danielle Hirsch, Reuven Azoury, Teddy A. Weiss, Iony Katz, Howard S. Kruth

Cells and Materials

The purpose of this study was to examine the ultrastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in glutaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scanning electron microscope analyses. These included secondary electron imaging, back scattering of primary electrons, energy dispersive X-ray analysis of selected spots followed by area mapping of calcium and phosphorus , and cathodoluminescence.

The information gathered from scanning of selected areas in the lesions by all the techniques …