Preparation of nonconducting samples for the scanning electron microscope

Abstract

Nonconducting samples for examination in the scanning electron microscope require a coating of conducting material to remove charge from the surface. Normally a layer of gold-palladium, nominally 500 AA thick, is evaporated on to the sample. Experiments using carbon as an alternative coating material showed that an approximately 800 AA thick carbon film can be used instead of metal film The results indicate that the carbon film of this thickness is nearly transparent to the secondary electrons used by scanning electron microscopes for image formation and as a consequence the substrate surface becomes visible.