A study of the electrical properties of the nanocontact between a conducting tip made of n-doped silicon, and the surface of a cleaned copper sample has been carried out. Current–voltage (I–V) curves have been performed in order to clarify the electrical nature of the nanocontact. Apart from the breakdown phenomenon and the noticeable laser diode effect on the I–V curves, the nanocontact can be modeled by a Schottky diode, in series with a resistance of a few kΩ, which probably reflects the resistance of the semiconducting probe. This fact is partially confirmed by a simple calculation of the resistance of the tip/cantilever system using a rough model. Topographical and electrical images have also been recorded for a given tip/sample bias. For a positive sample–tip voltage, the copper surface appears uniformly conducting over 20×20 μm2, and remains stable during the whole period of study (three weeks). This study thus allows one to have a better understanding of the effects which must be kept in mind when using semiconducting tips to analyze conductive metal surfaces such as copper. © 2002 American Vacuum Society.