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Very Low Energy Scanning Electron Microscopy
Hrnčiřík, Petr
Main goal of the work is in-situ comparison of signals in slow and Auger electrons in Scanning Electron Microscope. Construction of experimental device, computer simulations and calculations of properties of the device and interpretation of getting data are parts of the work.
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Auger electron spectro-microscopy
Hrnčiřík, Petr
The short escape depth of Auger electrons, the high lateral resolution, the chemical information about superficial elemental composition and the possibility of measuring the indepth distribution of elements (with utilisation of the ion sputtering) are the main advantages of the Auger electron spectroscopy (AES). When combined with the scanning electron miscroscope, AES can provide with image signal suitable for spectro-micrographs showing distribution of elements over the surface, i.e. the chemical mapping. This mapping can be advantageously compared with other SEM image signals in order to faciliate their interpretation.
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Scanning electron microscopy by slow and Auger electrons
Hrnčiřík, Petr
The main goal of the work is comparison of signals in slow and Auger electrons in situ in scanning electron microscope. The project includes completion of the experimental device, accomplishment of simulations and computations of its properties and interpretation of the obtained image data.
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Computer controlled SEM with Schottky cathode for imaging in slow and Auger electrons
Hrnčiřík, Petr ; Müllerová, Ilona
The ultrahighvacuum Scanning Electron Microscope has been built using the column of an old prototype (later produced as Tesla BS 350), some spare parts for BS 350 and new components, including computer controlled electronics. The whole vacuum system was extensively reconstructed, too. The Schottky cathode was introduced into the microscope instead of the original cold field emission gun. The advantage of this system includes a high current density, higher stability and lower vacuum demands at comparable performance as regards the resolution. Therefore it is possible to practice surface analysis with Auger electrons at a high resolution. The microscope was also adapted to the operation with slow and very slow electrons, again at high resolution, so that these two methods can be in situ compared.
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Rastrovací elektronová mikroskopie pomalými elektrony
Hrnčiřík, Petr ; Müllerová, Ilona
The largest sample thickness usable for transmission electron microscopy (TEM) is determined by the inelastic and elastic mean free paths (IMFP and EMFP). At primary electron energies normally used for TEM (>50 keV), both the mean free paths decrease as the primary energy is lowered. Attaining a sufficient penetration through a transmission sample of a given thickness is then simply a question of using a suitably high primary energy. As the primary energy is lowered below about 100 eV, however, IMFP is predicted to stop decreasing and to begin to grow again. This opens up the exciting possibility of very low voltage TEM, with poorer resolution but greatly reduced radiation damage compared to conventional TEM
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