Zur Abbildung von Isolierschichtdefekten im Elektronenspiegelmikroskop

Following the investigations on the imaging behaviour of homogeneous dielectric layers considerations on the possibilities of imaging simple layer inhomogeneities are discussed. These considerations imply a contrast amplification by charging phenomena. By definite variation of the substrate potential a distinction between geometrical layer defects (protrusions, indentations, holes) and electrical inhomogeneities of the insulating layer (regions of increased and decreased conductivity, resp.) is possible as shown by the experimental investigations. Criterions for distinguishing different cases can be given. The sensitivity for detecting inhomogeneities in non-covered dielectric layers is higher than in the case of those being covered with a conductive layer.