PIT AND MOUND FORMATION ON ARC-EVAPORATED CARBON THIN-FILM USING SCANNING-TUNNELING-MICROSCOPY

The etching of arc-evaporated carbon film with scanning tunneling micr oscopy (STM) was studied in comparison with that of highly oriented py rolytic graphite (HOPG). The arc-evaporated carbon film was etched wit h STM only in air or in water vapor and at a sample bias voltage posit ive to the tip. These etching characteristics were similar to those fo r HOPG. After the carbon film was etched by a high bias voltage, the i solated carbon film was frequently exfoliated by STM scanning. On the other hand, a mound was also formed on the arc-evaporated carbon film below the tip when a high bias voltage (similar to 4 V) was applied to the film. The surface mound was formed at both polarities of the tip voltage and was not affected by atmospheric conditions. The mound area was characterized by Auger electron spectroscopy (AES). The Auger spe ctrum showed that the substrate material migrated to the carbon film.