A cone formation theory of contamination in high resolution transmission electron microscopy

Abstract The formation theory of the contamination cone in high resolution transmission electron microscopy is discussed on the basis of a time dependent series of micrographs and their tilted images for evaluating the contamination process. For a high current density of an electron probe focused on the specimen, it was observed that two contaminated cones covering both upper and lower surfaces of a carbon substrate are formed as a function of the exposure time of the electron beam. From the measurement of the cross-section and height of contaminated cones, the contamination rate together with the volume rate, and time dependent shapes of various cones were analysed. The analysis was dependent on the diffusion cross-section and current density together with an average lifetime of adsorption molecules.