Abstract: The invention relates to a method for the manufacture of high voltage semiconductor devices with at least one planar junction with a variable charge concentration.The method consists in doping with impurities of a same type, in a region of monocrystalline semiconductor material, a first zone, and then a second zone which comprises the first, and so on, and in carrying out a subsequent heat treatment so as to provide a planar junction with a stepped profile and a concentration of impurities which decreases from the center to the periphery in a predetemined range. In this way the intensity of the surface electric field, when the junction is reverse biased, is reduced as a result of which it is possible to provide planar junctions having very high breakdown voltages of some thousands of volts.