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 kOmega, 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 X 20 mum(2), 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.