In a photodiode formed by a region of a first type inside a region of a second type, of a semiconductor substrate, the region of the first type includes a first zone including a dopant of the first type having a first concentration and a first depth. The region of the first type also has a second zone adjacent to the first zone in the dopant of the first type has a second concentration higher than the first concentration and a second depth smaller than the first depth. A method for making such a diode is also disclosed.