International audienceThe electron emission under electron impact between 10 eV and 2 keV is investigated with a Monte Carlo (MC) code in aluminum, silver, and silicon. The code is based on the complex dielectric function theory to describe the inelastic scattering and uses the Mott's model of partial waves to describe the elastic scattering. It takes into account both volume and surface plasmon excitations. The simulation results are compared with the experimental measurements of electron emission yields (EEY) and energy spectra of low energy electrons performed in ultrahigh vacuum on Ar-etched bulk samples. Our MC simulations at low energy are found to be in fairly good agreement with our experimental measurements. The peaks corresponding to the surface plasmon, the volume plasmon and its multiples and to the Auger transitions appear clearly on the energy loss spectra of aluminum, silver, and silicon. The simulated EEY are also in fairly good agreement with our measurements and with data from the literature. The EEY at normal incidence is studied for secondary and backscattered electrons. A focus is made for the EEY below 50 eV where a fairly good agreement is found with Bronstein and Fraiman's measurements on vacuum evaporated samples. Below 2 keV, for silver and aluminum, the total EEY is given for different angles of incidence θ. Some discrepancies are observed between our experimental measurements and our MC simulations for high angles of incidence. These discrepancies can be attributed to the modeling of surface plasmon excitations, surface oxidation, or roughness that occur during the Ar-etching process

International audienceThe electron transport at low and very low energy (10 eV-2 keV) is investigated with a Monte Carlo (MC) code in silicon and aluminum. The elastic scattering with nuclei is described by Mott's model of partial waves, whereas the inelastic collisions with electrons are described by the complex dielectric function theory. Comparisons of MC simulations with electron emission yields (EEY) and energy loss spectra experimentally measured in ultrahigh vacuum on Ar-etched samples are given. The practical ranges and the ionizing dose calculations are presented down to 10 eV for electrons in silicon and aluminum. The simulation results show a correlation between the EEY and the ionizing doses. At low energy, while the electrons stay in the first ~10 nm from the surface due to the elastic scattering, the EEY increases and the ratio of the ionizing dose over the incident energy decreases. Above 200 eV, when the electrons go deeper into the solid due to the inelastic scattering, the EEY decreases and the ionizing dose ratio increases

The electron transport in silicon at low and very low energy (10 eV-2 keV) is investigated with a Monte Carlo code. The elastic scattering with nuclei is described by Mott's model of partial waves, whereas the inelastic collisions with electrons are described by the complex dielectric function theory. The code has been validated by means of comparison with electron emission yields (EEY) and energy loss spectra experimentally measured in ultrahigh vacuum on an Ar-etched sample. Electron emission yields, practical ranges, and ionizing doses are presented for electrons in silicon down to 10 eV. 1 Index terms-Electron emission yield, low energy electrons, Monte Carlo code, practical range.

The effect of rough structures on the electron emission under electron impact between 10 eV and 2 keV is investigated with a new version of the low energy electromagnetic model of GEANT4 (MicroElec). The inelastic scattering, is modeled thanks to the dielectric function theory and the Mott's model of partial waves to describe the elastic scattering. Secondary electron emission is modeled for grooved and checkerboard patterns of different dimensions for aluminum and silver. The analyses is performed according to two shape parameters h/L and d/L, h being the height, L the width of the structures and d the spacing between two neighboring structures. The secondary electron emission is demonstrated to decrease when h/L and d/L ratios increase. When the height reaches 10 times the lateral dimensions, the electron emission yield is divided by two compared to that of a flat sample. The optimization of the two aspects ratios lead to a reduction of the electron emission yield of 80 % for grooved patterns, and of 98 % for checkerboard patterns. This purely geometric effect is similar for aluminum and silver materials. A simple analytical model, capable to reproduce the effect on the electron emission yield of checkerboard and grooved patterns, is proposed. This model is found to be in good agreement with the Monte Carlo simulations and some experimental measurements performed in our irradiation facility.