Patent ID: 7335942

Claim:
A sensor for the investigation of sample surfaces or fields adjacent to the sensor, the sensor comprising at least one field effect transistor (FET) formed in a substrate comprising at least one semiconductor material and having source and drain regions defined in said substrate and being of the opposite conductivity type from said substrate, the substrate including a three-dimensional projecting region with a tip region, a channel region defined in at least the tip region of said three-dimensional projecting region and extending between said source and drain regions, and an electrode for the application of a setting voltage in order to electrically pre-set an electrical resistance of said channel region, said field effect transistor being adapted by said channel region in said tip region of said three-dimensionally projecting region to cooperate with at least one of a field, a charge and a sample disposed in the proximity of said tip region external of the tip region and acting as an external gate.