Fringe fields of the Wien-filter aberration corrector for low-voltage SEM

摘要

The correction of chromatic and spherical aberration is necessary to significantly improve the spatial resolution of a low-voltage scanning electron microscope. Aberration correction can be achieved using a long double-focussing Wien filter. Here we discuss the effect of aberrations of weakly focussing filters and their fringe fields on the SEM probe resolution. Means are presented to reduce these aberrations to significantly improve the resolution.