Introduction

In our rapidly expanding technology, the scientist is required to observe, analyze, and correctly explain phenomena occurring on a micrometer (µ,m) or submicrometer scale. The scanning electron microscope and electron microprobe are two powerful instruments which permit the observation and characterization of heterogeneous organic and inorganic materials and surfaces on such a local scale. In both instruments, the area to be examined, or the microvolume to be analyzed, is irradiated with a finely focused electron beam, which may be static or swept in a raster across the surface of the specimen. The types of signals produced when the electron beam impinges on a specimen surface include secondary electrons, backscattered electrons, Auger electrons, characteristic x-rays, and photons of various energies. These signals are obtained from specific emission volumes within the sample and can be used to examine many characteristics of the sample (composition, surface topography, crystallography, etc.).