Abstract:
We report on the properties of electric fields generated as a result of electron irradiation of
dielectrics in a low vacuum scanning electron microscope. Individual field components produced by
(i) ionized gas molecules located outside the sample surface and (ii) subsurface trapped charge were
detected by measurements of changes in (i) primary electron landing energy and (ii) secondary
electron (SE) emission current, respectively. The results provide experimental evidence for a
recently proposed model of field-enhanced SE emission from electron irradiated insulators in a low
vacuum environment [Toth et al., J. Appl. Phys. 91, 4479 (2002)]. Errors introduced into x-ray
microanalysis by the electric fields generated by ionized gas molecules can be alleviated by
minimizing the steady state ion concentration by the provision of efficient ion neutralization routes.
It is demonstrated how this can be achieved using simple sample–electrode geometries.
