Secondary electron imaging of titania thin film for surface potential analysis

Abstract

We demonstrate the surface potential sensitivity of secondary electron (SE) imaging of titania thin film by scanning electron microscopy (SEM), and discuss the image formation mechanism. The 1‐nm titania film on Si substrate was imaged as bright region against the substrate. The SE image of the film varied with SE detector, but did not with primary electron energy. The contrast of the film was reversed by only 1‐nm carbon deposition. This result suggests that a slight change of surface potential altered the efficiency of secondary electron emission. This high sensitivity of secondary electrons to the surface potential is promising for improvement of thin‐film observation by SEM. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)