Skirting effects in the variable pressure scanning electron microscope: limitations and improvements.

A new approach has been initiated to improve the spatial lateral resolution of the X-ray microanalysis and the backscattered electrons modes in variable pressure or environmental scanning electron microscope (VP-ESEM). This approach is based on correlation between two concepts: the electron beam skirt radius in the gas (R(S)) and the generation volume radius (R(X)) of X-ray signals and the generation volume radius (R(BSE)) of backscattered electrons in the material. In order to follow the relationship between R(S), R(X) and R(BSE), PMMA polymer, silicon oxide and aluminium are used. The results of the simulation show the existence of the best lateral resolution conditions named R (P, E) depending on the pressure and the energy for each material. This approach will enable us to propose some optimal experimental conditions to characterize different materials.