Increasing compositional backscattered electron contrast in scanning electron microscopy

Signal detection and imaging methods for MEMS electron microscope

In the paper, new detection methods that can be used to detect signals in a miniature MEMS (Micro-Electro-Mechanical System) electron microscope were presented. The methods were designed to fit the structure of the developed MEMS microscope, equipped with an electron-optical microcolumn and a scanning system based on an octupole deflector. In the experiments carried out, imaging was performed using a system of three silicon detectors placed above, below, and at the sample level and integrated with the octupole deflection system. Measurements were carried out under different pressure conditions (vacuum and atmospheric pressure) and for different detector bias voltage and electron beam energy. Good quality images were obtained using all three detectors, both in vacuum and in air. The results presented indicate that in the final implementation of the MEMS electron microscope, all three detection systems can be successfully incorporated.

Backscattered electron detector for 3D microstructure visualization in scanning electron microscopy

A new configuration of semiconductor detectors for backscattered electrons for a scanning electron microscope (SEM) is presented. The result of the optimization was the possibility to extract the information about the spatial relief (3D topology) of the sample and its subsurface structure (3D tomography) in the simplest way. The detector consists of 8 sensors-semiconductor plates, positioned in a certain way. The proposed method was tested on real structures having a surface micro relief or a subsurface volume structure. Experiments and simple calculations show increased effectiveness and a high signal-noise ratio in the proposed method. This is important, particularly for studying the radiation-sensitive biomedical tissue in SEM.

Surface potential and charging of polymer films submitted to defocused electron beam irradiation

The surface potentials and dynamic charging properties of polymers subjected to electron irradiation in scanning electron microscopy are investigated by using a novel method applied in parallel with simulation and experimental methods. We perform our simulation through a parallel computing method with various microscopic parameters. The results show that under the given microscopic parameters, the charging time concomitantly decreases as the film thickness, electron mobility, trap cross and recombination rate increase. The surface potential decreases as electron energy, beam current density, capture cross section, sample thickness and electron-hole recombination rate increase and as electron mobility decreases. Charging time increases with increasing beam density, sample thickness, recombination rate and change in capture cross-section, and decreases with increasing electron mobility. The primary-electron energy exhibits an inflection point at 35 keV. This study offers an intuitive analytical and measurement method for understanding microscopic charge characteristics in electron-based surface microscopy.