Scanning tunneling microscope modifications of amorphous Ge-Sb-Te films

Surface modifications produced in Ge-Sb-Te films by a scanning tunneling microscope have been studied. Three kinds of modifications appear to depend upon the applied voltages to the tip. Positive tip voltages of about 2 V produce depressions accompanying peripheral mounds, which can be accounted for as mechanical scratching by the tip. When the humidity is higher than similar to50%, tip voltages between 5 and 10 V produce depressions with no peripheral mounds, and negative tip voltages of about -10 V produce expansions. These humidity-assisted depression and expansion are assumed to be caused by electrochemical etchings and anodic oxidation processes. (C) 2003 Elsevier B.V. All rights reserved.