A high-voltage NMOS transistor with low threshold voltage. The body doping that defines the channel region is in the form of a deep p-well. An additional shallow p-doping is arranged as a channel stopper on the transistor head. This additional shallow p-doping is produced in the semiconductor substrate at the end of the deep p-well that faces away from the channel region, and extends up to a location underneath a field oxide region that encloses the active window. The leakage current of the parasitic transistor at the transistor head is suppressed with the channel stopper.